Glossary of Photonics Terms (original) (raw)
Photonics Glossary and List of Formula Symbols
On this page, you first find the glossary of photonics terms, which is based on the definitions in the Encyclopedia articles. These have been carefully worked out, such that they can be considered as authoritative.
Further below there is a list of common formula symbols.
This page summarizes the definitions of photonics terms, as they appear below the headings of many of the Encyclopedia pages.
| A | B | C | D | E | F | G | H | I | J | K | L | M |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
A
a measure for the chromatic dispersion of a transparent material
a 2-by-2 matrix describing the effect of an optical element on a laser beam
the logarithm with base 10 of the inverse transmittance
the fraction of incoming radiant flux which is absorbed by an object
a process where light energy is converted to another form of energy
a logarithmic measure for the distributed absorption in a medium
the length over which absorption reduces the optical intensity to 1/e of its initial value
acceptance angle in fiber optics
the maximum incidence angle of a light ray which can be used for injecting light into a fiber core or waveguide
optical devices or setups with minimized chromatic aberrations
acousto-optic devices for deflecting and scanning laser beams
acousto-optic frequency shifters
acousto-optic devices for shifting the optical frequency of a laser beam
optical modulators based on the acousto-optic effect
acousto-optic modulators used for Q switching of lasers
acousto-optic devices which can be used for filtering light, controlled with an RF input
a field of metrology which is based on counting radiation quanta instead of registering powers
optical fibers containing laser-active dopants in the fiber core
a technique of mode locking, based on active modulation of the intracavity losses or the round-trip phase change
a class of techniques where wavefront distortions are actively compensated
a technique for mode locking a laser, using a nonlinear interaction in an external resonator
a pulse compression technique based on the adaptation of solitons to slowly varying propagation parameters
optical systems which output parallel rays for parallel input rays
solid-state lasers based on alexandrite (Cr3+:BeAl2O4) crystals
lasers used for alignment purposes
alignment sensitivity of optical resonators
the sensitivity of a laser, an optical resonator or some other device with respect to misalignment
laser systems containing solid-state devices only, in particular no discharge lamps or gas or dye lasers
the factor by which the power of a signal is amplified
amplified spontaneous emission
a process where spontaneously emitted radiation (luminescence) is amplified
amplifiers consisting of several stages
noise introduced to a signal in an amplifier device
light with an intensity noise below the shot noise level
prisms pairs for reshaping laser beams
optical thin-film coatings for reducing reflections from surfaces
apertures which limit the angular range of received input light of imaging systems
gas discharge lamps based on an electrical arc, or continuously operating gas discharge lamps
gas lasers based on light amplification in ionized argon in a gas discharge
optical filter or multiplexer devices based on arrays of waveguides
optical elements with non-spherical surfaces
a kind of optical aberrations; alternatively, a defect of optical lenses or a property of laser beams
optical instruments for precisely measuring angular alignments
devices for measuring the intensity or field autocorrelation function of light, mostly used for determining the duration of ultrashort pulses
photodiodes with internal signal amplification through an avalanche process
lenses with a conical surface
B
a measure of the nonlinear phase shift of light, e.g. in an amplifier
adjustable waveplates (retarder plates) containing three birefringent plates
a method of photodetection which is sensitive to differences in optical powers but not to common noise
lenses which have the geometric form of a sphere
a range of energies for which there are no states of carriers in a medium
the width of some frequency or wavelength range
pulses with a duration as short as possible with their optical spectrum
product of length and maximum signal bandwidth of a fiber-optic link
devices for collimating optical beams
a class of techniques for power scaling of laser sources by combining the outputs of multiple devices
optical systems for sending laser beams from sources to applications
a measure for how fast a laser beam expands far from its focus
devices for blocking and absorbing light beams
optical devices for modifying the beam radius of a collimated beam
devices for producing beam profiles with homogeneous intensity distribution
product of the beam radius in a focus and the far-field half-angle beam divergence
fluctuations of the propagation direction of a laser beam
devices for measuring the intensity profile of a laser beam
a measure for how well a laser beam can be focused
a measure of the transverse extension of a light beam
optical devices for modifying the shapes of laser beams
devices for blocking or releasing light beams
devices for splitting a laser beam into two or more beams
location with minimum beam radius
an oscillation of the optical intensity arising from the superposition of light with different optical frequencies
a relation for the dependence of absorption coefficients on concentrations
propagation losses in an optical fiber (or other waveguide) caused by bending
tunable phase retardation plates containing a single uniaxial crystal
the polarization dependence of the refractive index of a medium
a technique of phase matching based on the birefringence of a crystal material
devices for wavelength tuning of lasers, based on birefringence and polarization rotation
average fraction of wrongly transmitted bits in a communication link
coatings with strong light absorption
lasers emitting blue light
reflecting structures with a periodic refractive index modulation
mirror structures based on Bragg reflection at a period structure
coplanar plates inserted into beams at Brewster's angle
transparent plates which are oriented at Brewster's angle such that parasitic reflection losses are minimized.
an angle of incidence at which there is no reflection of p-polarized light at an uncoated optical surface
a term mostly used in a qualitative way, related to the output power and beam quality of a laser; quantitatively: often used instead of radiance or luminance
optically pumped devices where the generated optical output has a higher brightness than the optical pump source
a nonlinear scattering effect involving acoustic phonons
laser diodes with a strongly asymmetric shape of the emitting region
lasers based on bulk crystals as gain media
lasers which emit burst (bunches) of light pulses
C
optical instruments for recording still or moving images
a set of points which characterize the function of an optical element or a group of elements in Gaussian optics
the offset between the optical phase and the maximum of the wave envelope of an optical pulse
the concept of relating effects to causes, or the compatibility of phenomena with this concept
resonators for light (or for microwaves)
a method for extracting intense short or ultrashort pulses from a laser, using an optical switch in the laser resonator
laser gain media which have a ceramic (polycrystalline) microscopic structure
waveguides with the form of a channel at the surface of a host medium
luminescence arising from chemical reactions
time dependence of the instantaneous frequency of an optical pulse
Bragg-type dispersive mirrors with a spatial variation of the Bragg wavelength
a technique for amplifying pulses to very high optical intensities while avoiding excessive nonlinear pulse distortions or optical damage
image distortions caused by wavelength-dependent optical effects
the frequency dependence of the phase velocity in a transparent medium
an objective specification of measured or calculated colors, used in addition to luminance (brightness)
chromium-doped laser gain media
laser gain media doped with chromium ions
standardized optical spectra for white light sources
devices which can remove light from a fiber cladding
modes in optical fibers (or other waveguides) which are not restricted to the region around the core
cleaning of optical elements
preparing fiber ends with clean optical surfaces by controlled breaking
the tendency e.g. of laser-active ions in laser gain media to form clusters in their host medium
a fixed phase relationship between the electric field values at different locations or at different times
a measure of temporal coherence, expressed as the propagation distance over which the coherence significantly decays
a measure of temporal coherence, expressed as the time over which the field correlation decays
a class of methods for beam combining, requiring mutual coherence of the combined beams
a special kind of pure quantum-mechanical states of light
mirrors which can reduce the heat load in an optical system by reflecting only visible radiation
laser beams with weak divergence
crystal defects which introduce additional light absorption or emission features in crystalline materials
a quantity which can be used for estimating how accurately colors can be perceived when using a specific light source
mathematical spaces for representing color values
the temperature of a blackbody radiator which leads to a color impression of the thermal light which matches most closely the light of a light source
vision with some capability for spectral analysis of the light
instruments for measuring quantities which are relevant for color perception
the science and technology of objectively measuring optical properties related to color impressions for the human eye
interferometers where the sensitivity to mechanical noise is reduced by largely using a common optical path for the interfering light beams
laser crystals consisting of several parts of different materials or with different chemical compositions (e.g. doping concentrations)
lenses or lens systems for conditioning light from an illumination source
optical microscopes with enhanced depth resolution based on the confocal measurement principle
pairs of planes where an optical system images one into the other and vice versa
operation mode of a laser with continuous light emission
the phenomenon that laser action at one wavelength can facilitate lasing at another wavelength
end pieces attached to optical fibers, containing no fiber core
prisms with three reflecting surfaces which act as retroreflectors
infrared lasers based on a gas mixture in which light is amplified by carbon dioxide molecules
phase matching of a nonlinear interaction by adjustment of a propagation direction
a nonlinear effect where the optical intensity of one beam influences the phase change of another beam
optical glasses with low chromatic dispersion and tentatively a low refractive index
lasers where the gain medium is operated at cryogenic temperatures
temperature-controlled ovens for keeping optical crystals at the desired operation temperature
multilayer mirrors where the reflecting parts consist of a monocrystalline material
optical elements made according to customer-specific specifications
a wavelength above which a guided mode of a waveguide ceases to exist
lenses which focus or defocus light only in one direction
D
a current from a photodetector which occurs even in the absence of a light input
dB relative to a reference power of 1 mW
a logarithmic measure for power ratios, applied e.g. to optical powers or to noise powers
mirrors which can be deformed in a controlled manner, e.g. for wavefront correction in adaptive optics
the phenomenon that the nonlinear polarization of a medium does not instantly follow the electric field strength
losses of optical power in a laser resonator, caused by depolarization e.g. in a laser crystal
the distance between the nearest and furthest objects that can be imaged with reasonably sharp focus for a given focus setting
the half width of the range of longitudinal positions in which a reasonable focus for a film or image sensor is achieved
the inverse of the noise equivalent power
product of the diameter (at a beam waist) and the divergence angle of a laser beam
circular (or approximately circular) openings through which light can travel
mirrors with significantly different reflection or transmission properties at two different wavelengths
wavelength-dependent transmission, alternatively polarization-dependent absorption
thin-film coatings made of transparent dielectric materials, e.g. for laser mirrors or anti-reflection coatings
electrically insulating materials
mirrors consisting of multiple thin layers of different transparent optical materials
the range of time delay values for signals in a telecom fiber
wave phenomena which occur when light waves hit some structure with variable transmission or phase changes
optical components containing a periodic structure which diffracts light
beams with a minimum possible beam divergence for a given waist radius
optical elements with operation principles based on diffraction of light
devices which scatter light such that its spatial coherence is substantially reduced
a type of semiconductor laser containing a one-dimensional array of broad-area emitters
semiconductor laser devices based on laser diodes
arrangements of multiple diode bars, delivering very high output power
solid-state lasers which are pumped with laser diodes
the inverse of the focal length
diode lasers which are directly used e.g. for material processing
the dependence of the phase velocity in a medium on the optical frequency or the propagation mode
the control of the overall chromatic dispersion of a system by adding optical elements with a suitable amount of dispersion
dispersion compensation modules
modules used for dispersion compensation
the use of tailored chromatic dispersion to enhance the function of optical devices or systems
optical fibers where the chromatic dispersion changes monotonously along the propagation direction
fibers with a non-standard zero dispersion wavelength
mirrors which provide some amount of chromatic dispersion for the reflected beam
a linearly propagating wave which is split off by a soliton wave under certain conditions
distance measurements with lasers
measurements of distances using laser light
fiber amplifiers in fiber-optic data links, where the amplification occurs within a large length of transmission fiber
distributed Bragg reflector lasers
lasers containing distributed Bragg reflectors as end mirrors
lasers where the whole laser resonator consists of a periodic structure, in which Bragg reflection occurs
a method of amplifying intense ultrashort pulse while avoiding excessive nonlinear effects
lasers with a solid-state gain medium containing a laser-active dopant
the concentration of some dopant, e.g. of laser-active ions in a laser gain medium
broadening of the linewidth of atomic transitions, caused by random motion of the emitting atoms
a technique of laser cooling based on velocity-dependent absorption processes
a limit for the temperature which is achievable with certain laser cooling techniques
two closely spaced optical pulses
optical fibers with different waveguide structures for pump and signal light
lasers based on liquid or solid dyes as gain media
E
edge-emitting semiconductor lasers
semiconductor lasers emitting light along the plane of the wafer
a quantitative measure of the area which a waveguide or fiber mode effectively covers in the transverse dimensions
effective nonlinear coefficient
a coefficient for quantifying the strength of a nonlinear interaction
a number quantifying the phase delay per unit length in a waveguide, relative to the phase delay in vacuum
effective transition cross-sections
a modified type of transition cross-sections which apply to optical transitions between Stark level manifolds
the phenomenon that the refractive index of a material can be modified with an electric field
optical modulators based on the electro-optic effect
an optical sampling technique based on the electro-optic effect
the science and technology around the electro-optic effect; alternatively: optoelectronics or even the whole area of photonics
optical modulators based on the Franz–Keldysh effect
luminescence arising from electrical influences
electronic dispersion compensation
a method for mitigating the effects of chromatic dispersion in fiber-optic communication links with electronic components in the receiver
a measure for how strongly an object emits and absorbs thermal radiation
a technique of optically pumping a laser medium in a direction along the laser beam
the phenomenon that dopant ions in laser-active media can exchange excitation energy among each other
optical cavities for exploiting the resonant enhancement of the power of circulating light
the apparent apertures of an optical system, seen from the object or image side
fiber amplifiers based on erbium-doped optical fibers
laser gain media doped with erbium ions
erbium-ytterbium-doped laser gain media
laser gain media which are doped with both erbium (Er) and ytterbium (Yb)
monolithic interferometric devices containing two parallel reflecting surfaces
waves with rapidly decaying amplitude and no power transport
gas discharge lamps where ultraviolet radiation is generated by spontaneous emission from excited dimers
lasers where optical amplification occurs in a plasma containing excited dimers (or other molecules) with an anti-binding electronic ground state
absorption of light by ions or atoms in an excited electronic state, rather than in the electronic ground state
non-monolithic diode lasers where the laser cavity (resonator) is completed with external optical elements
lasers emitting in a wavelength region with relatively low hazards for the human eye
F
a measure for the open aperture of a photographic objective
interferometers consisting of two highly reflecting mirrors, forming a standing-wave resonator
a laser diode with a laser resonator exhibiting substantial reflections at both ends, but no distributed reflections inside
a non-reciprocal optical device sending light from each input to the next output port
the rotation of the linear polarization direction in a medium exposed to a magnetic field
optical isolators based on the Faraday effect
the combination of a Faraday rotator and a mirror
devices which can rotate the polarization state of light, exploiting the Faraday effect
lasers emitting light pulses with durations between a few femtoseconds and hundreds of femtoseconds
fibers supporting only few guided modes
optical amplifiers with doped fibers as gain media
a one- or two-dimensional array of optical fibers
reflective structures in the core of an optical fiber with a periodic or aperiodic perturbation of the effective refractive index
bundles of optical fibers
cables containing one or several optical fibers
the area(s) around the core of an optical fiber
instruments for preparing fiber ends with clean optical surfaces
some length of optical fiber wound up to a coil
devices for collimating the light coming from a fiber, or for launching collimated light into the fiber
connectors used as terminations of optical fiber cables
the region in an optical fiber which guides light
fiber devices for coupling light from one or several input fibers to one or several output fibers, or from free space into a fiber
the fabrication of optical fibers
the effect that an optical fiber "burns" from the output end under the influence of an intense laser beam launched into the other end
permanent or removable connections between fiber ends
lasers with a doped fiber as gain medium, or (sometimes) just lasers where most of the laser resonator is made of fibers
fiber lasers versus bulk lasers
Fiber lasers are based on fiber waveguides, while bulk lasers are based on bulk laser crystals.
optical systems for launching light into optical fibers
fiber loops which act as reflectors
optics based on optical fibers
a protected and connectorized fiber-optic cable
devices with multiple ports for fiber-optic connectors
fiber polarization controllers
devices which allow one to control the state of polarization of light within fibers
a piece of glass from which an optical fiber can be drawn
arrangements for routing some number of fiber inputs to some fiber outputs, with a fixed or reconfigurable routing matrix
software for numerical simulations on fiber devices
joints between fibers for efficient transfer of light from one fiber to the other
the technology of providing data connections to private homes via optical fibers rather than electric cables
diode laser devices where the generated light is coupled into an optical fiber
optical attenuators for use in fiber optics, usually used with fiber connectors
optical communication links where the signal light is transported in fibers
communication systems consisting of fiber-optic links
transparent plates containing many optical fibers
fiber-optic couplers for sending pump and signal light into an amplifier or laser fiber
optical sensors based on fiber devices
fiber-optic plates which are tapered for obtaining some image magnification
a kind of long and thin optical waveguides which can be bent to some degree
lenses in imaging instruments which affect the field of view
the angular extent of the field which can be observed with an optical instruments or the eye
apertures which limit the field of view of imaging systems
the free spectral range divided by the FWHM width of the resonances of an optical resonator
metal-coated mirrors reality metallic mineral coating is on the front surface of the mirror substrate
interferometers for investigating optical surfaces
gas discharge lamps which are used for generating intense light pulses
optics realized with flat and thin devices
a light beam with a flat intensity profile
optical glasses with strong chromatic dispersion (low Abbe number) and tentatively a high refractive index
optical energy per unit area
luminescence arising from irradiation with light
a technique for acquiring microscopic images using fluorescence which is excited in the sample
spectroscopy which is based on the analysis of fluorescence light
lamps which emit fluorescent light, usually generated by irradiation of a phosphor with light from an electric gas discharge
optical fibers based on fluoride glasses
glasses made from compounds of fluorine e.g. with zirconium, aluminum or indium
the distance between an objective and its focal point
a measure of how strongly an optical system focuses or defocuses light
arrays of light detectors placed in the focal plane of an imaging system
points to which parallel input rays are concentrated by an optical system, and the planes going through those points
a point where different light rays meet, the optimum adjustment of an imaging system, or a location along a beam where the beam diameter reaches a minimum
transitions between different energy levels of some atoms or ions for which dipole transitions are suppressed via symmetries
four-level and three-level laser gain media
laser gain media without/with reabsorption from the lower laser level
an interaction of light waves based on a <$\chi^{(3)}$> nonlinearity
the description of light propagation based on transverse spatial Fourier transforms
Fourier transform spectroscopy
a method for spectroscopy rare an optical spectrum is computed from raw data with a Fourier transform
laser devices where light amplification occurs by interaction with fast electrons in an undulator
frequency spacing of the axial modes of an optical resonator
free-space optical communications
optical data transmission through free space, usually through air or vacuum, often involving a laser beam
optical spectra consisting of equidistant lines
the phenomenon that an input wave in a nonlinear material can generate a wave with twice the optical frequency
the field of technology dealing with precise frequency measurements
noise of the instantaneous frequency of an oscillating signal
the phenomenon that an input laser beam generates a beam with four times the optical frequency
the phenomenon that an input laser beam generates a beam with three times the optical frequency
frequency-resolved optical gating
a technique for the complete characterization of ultrashort optical pulses
lasers where the optical frequency of the output is made particularly stable
equations for the amplitude coefficients of transmission and reflection at the interface between two transparent homogeneous media
lenses where the surface profile has annular steps
a parameter determining the regime of diffraction effects
light reflections at optical interfaces
mode locking with a single pulse circulating in the laser resonator
amorphous silicon dioxide
a technique of making low-loss fiber joints by fusing fiber ends together
an equation used for calculating emission cross-sections of laser gain media
G
a measure of the strength of optical amplification
the width of the optical frequency range in which significant gain is available from an amplifier
a firm limitation of the gain of some amplifier or laser, usually caused by lasing action
small-signal gain of an optical amplifier per unit pump power or per unit stored energy
a technique for making the gain spectrum of an optical amplifier device flatter over a certain optical frequency range
guiding of light based on spatially inhomogeneous optical gain
the phenomenon that the bandwidth of light can be reduced during amplification in a medium with a limited gain bandwidth
the phenomenon that the gain of an amplifier is reduced for high input signal powers
a technique for generating short optical pulses in a laser by modulating the laser gain
a cell filled with some gas, normally used in laser absorption spectroscopy
light sources which are based on an electrical discharge in an ionized gas or metal vapor
lasers with a gas (or plasma) as gain medium
light beams where the electric field profile in a plane perpendicular to the beam axis can be described with a Gaussian function, possibly with an added parabolic phase profile
a framework for describing optical phenomena, which is based on geometrical optics and the paraxial approximation
pulses with a temporal intensity profile which has a Gaussian shape
a concept of optics which is based on the propagation of light rays, ignoring wave properties of light
optical fibers based on germanate glasses
spectroscopic data concerning absorption and amplification in an active fiber
Gires–Tournois interferometers
linear optical resonators used for introducing chromatic dispersion
solid-state lasers with a glass as gain medium
a timing jitter originating from fluctuations of the center frequency
an additional phase shift occurring in the propagation of focused Gaussian beams
optical fibers with a continuously varying refractive index in the radial dimension
lenses which utilize a radial variation of refractive index
lasers emitting in the green spectral region
a measure of the time delay experienced by narrow-band light pulses in an optical device
the frequency dependency of the group delay, or (quantitatively) the corresponding derivative with respect to angular frequency
the ratio of the vacuum velocity of light to the group velocity in a medium
the velocity with which the envelope of a weak narrow-band optical pulse propagates in a medium
the frequency dependence of the group velocity in a medium, or (quantitatively) the derivative of the inverse group velocity with respect to angular frequency
the phenomenon that pulses become temporally separated in a medium due to different group velocities, or (quantitatively) the difference of inverse group velocities
waves for which diffraction is suppressed by a waveguide structure
H
incandescent lamps with a halogen filling, allowing for higher operation temperatures
mode locking of a laser where multiple pulses are circulating in the laser resonator with equal temporal spacing
an analytical equation describing the evolution of ultrashort pulses in a laser resonator
gas lasers based on a helium–neon mixture
propagation modes or resonator modes which are described with Hermite–Gaussian functions
laser diodes with particularly high radiance (brightness)
the phenomenon that very high harmonics of an intense input laser beam are generated in a gas
high intensity discharge lamps
gas discharge lamps operating with high power density
pulsed lasers with a high output pulse energy
high-power fiber lasers and amplifiers
fiber lasers and fiber amplifiers with high output powers of e.g. larger than 100 W
lasers emitting very high optical powers
transverse modes of a resonator or waveguide, excluding the fundamental (axial) modes
optical pulses in a nonlinear and dispersive medium which exhibit periodic oscillations of their temporal and spectral shape
optical fibers exhibiting relatively strong nonlinear effects
optical fibers with a hole on the fiber axis
methods for recording and reconstructing three-dimensional images
the increase in the linewidth of an atomic transition caused by effects which affect different radiating or absorbing atoms in the same way
saturation of an absorption or gain, where the shape of the absorption or gain spectrum is not modified
mirrors which can reduce the heat load in an optical system by reflecting infrared radiation
Raman scattering processes involving two pump photons
the smallest focusing distance of an imaging instruments for which objects at infinity appear with reasonably sharp focus
imaging which provides images with an optical spectrum corresponding to each pixel
I
the incident luminous flux per unit area on a surface
image intensifiers and image converters
instruments which can intensify images acquired under faint light conditions, or convert images to other wavelengths
planes which are conjugate to an object plane, so that objects are imaged there
optoelectronic sensors which can be used for imaging
mapping objects points to image points; applications involving such methods
creation of an optical image using a single lens
optical pumping of a laser or amplifier directly from the lower to the upper laser level, or at least directly into the upper laser level
light sources which produce thermal radiation from an electrically heated filament
fluids with a refractive index similar to that of other optical materials, typically used for suppressing light reflections
lasers used for industrial purposes, for example for laser material processing
cameras which work with infrared light
detectors for infrared light
devices emitting infrared radiation
invisible light with wavelengths roughly between 750 nm and 1 mm
optical elements and systems which are suitable for infrared light
instruments for observing scenes with infrared light
the increase in the linewidth of an atomic transition caused by effects which act differently on different radiating or absorbing atoms
gain saturation effects which alter the shape of the gain spectrum
a technique for enforcing operation of a laser on a certain optical frequency by injecting light with that frequency into the laser resonator
a technique for enforcing narrowband operation of a laser or optical parametric oscillator by injecting light into its resonator
power losses due to insertion of a device
temporal derivative of the oscillation phase divided by <$2\pi$>
the technology dealing with the construction of photonic integrated circuits
devices with a diffusely reflecting inner surface, used for certain optical measurements
devices which can be used to modulate the intensity (power) of a light beam
noise of the optical intensity or power of a laser beam
a range of phenomena associated with the superposition of waves
optical filters based on interference effects
optical devices utilizing the phenomenon of interference
safety devices for automatically switching off a laser power or interrupting a laser beam
the phenomenon that the group velocity of light propagating in a waveguide structure depends on the waveguide mode
intracavity frequency doubling
frequency doubling with a nonlinear crystal within the laser resonator
intracavity laser absorption spectroscopy
a method of laser spectroscopy, based on the evolution of the optical spectrum of intracavity radiation under the influence of narrowband absorption features
pumping a laser or OPO with intracavity radiation from another laser
gas lasers where ions are used as laser-active agents
the radiant flux (optical power) received by a surface per unit area
J
K
sidebands in the spectrum of certain mode-locked lasers, related to a periodic disturbance of soliton pulses in the laser resonator
a nonlinear interaction of light in a medium with an instantaneous response, related to the nonlinear electronic polarization
a lensing effect arising from the Kerr nonlinearity
a technique for mode locking a laser, exploiting nonlinear self-focusing
mathematical relations between absorption coefficient and refractive index of media
a theory predicting the durations of pulses from actively mode-locked lasers
L
Lambertian emitters and scatterers
light emitters or scatters where the radiance towards an observer is independent of the viewing direction
power supplies for lamps
lasers which are pumped with flash lamps or arc lamps, or in rare cases with tungsten halogen lamps
optical elements with a diameter of e.g. 100 mm or more
optical fibers with relatively large mode areas and a single transverse mode or only a few modes
optical fibers with relatively large fiber core
the fabrication of 3D structure using laser sintering, melting or polymerization
the removal of solid material using intense laser light
methods of absorption spectroscopy using laser light
laser-based processes which create suitably shaped solid parts from a powder or liquid
applications involving laser devices
methods of assessing detailed properties of laser beams
light beams propagating dominantly in one direction
the deposition of a metallic cladding layer on a metallic base surface, aided by laser light
the removal of unwanted substances from surfaces by applying intense laser radiation
the deposition of a coating layer on a base surface, aided by laser light
a variety of techniques for reducing the temperature (i.e., the random motion) of small particles such as atoms or ions
devices used for cooling of high-power lasers
transparent crystals with laser-active dopants, used as laser gain media
cutting of material using intense laser beams
the design of a laser device, or the process of working out such a design
the process of developing a laser device
devices for collimating the output of laser diodes
electronic current supplies for one or several laser diodes
modules containing diode lasers, and possibly also some optics, cooling devices, electrical elements, etc.
various test procedures applied to laser diodes in qualification, regular batch testing or burn-in
semiconductor lasers with a current-carrying p–n junction as the gain medium
the generation of holes with laser beams
the temporal evolution of quantities such as the optical power and gain in a laser
media for laser amplification
doped glasses which can be used as laser gain media
small bright spots in the sky, generated with laser beams for use in astronomy with adaptive optics imaging
hardening materials (usually steel or cast iron) with a laser treatment
assemblies containing a mounted gain medium and means for pumping and cooling, or the complete optical parts of a laser, or assemblies for directing a laser beam to a workpiece
light generated with a laser device
optical elements made specifically for certain laser lines
narrow spectral lines obtained from lasers
methods of laser material processing which involve the controlled removal of material
a group of methods for labeling materials with lasers
a general term for a wide range of methods for material processing using laser radiation
machining with laser radiation on a micrometer scale
a technique for generating microscopic images by scanning objects with a laser
high-quality mirrors used in laser resonators and other optical setups
the investigation of phenomena and quantitative relations in lasers, using theoretical models, computational methods and simulation; used for problem analysis and design optimization
fluctuations of various parameters of laser light, such as the optical power and phase
optical elements and systems used with lasers - either in lasers or for transmitting and manipulating laser light
the field of physics dealing with phenomena in lasers
devices used for pointing at items with laser beams
the part of a laser processing machine which is used to direct a laser beam to a workpiece
devices for measuring distances to objects, using lasers
optical resonators serving as basic building blocks of lasers
laser crystals (or glasses) in the form of (usually cylindrical) rods
safety of the use of laser devices
the protection of eyes against laser hazards
devices for scanning the direction of a laser beam
joining parts with a solder, which is heated with a laser beam
descriptions of essential properties of a laser system, such as performance parameters, dimensions, and operating conditions
light patterns resulting from the reflection of coherent light at rough surfaces
methods where the interaction of laser light with matter is utilized
the modification of surface properties of materials using processes with laser beams
an operation condition of a laser where laser emission just starts to occur
optical transitions where stimulated emission is used to obtain optical amplification
cards used for visualizing laser beams in non-visible spectral regions
joining of parts by melting them with a laser beam
a kind of spark, initiated by intense laser light
damage of optical components induced by laser radiation
devices generating visible or invisible light, based on stimulated emission of light
lasers for material processing
lasers which are suitable for application in laser material processing
lasers which are specifically suitable for applications in quantum photonics
lasers which are specifically suitable for applications in Raman spectroscopy
the quantum-optical phenomenon of laser emission occurring without the presence of a population inversion
a concept for quasi-bound waveguide modes with propagation losses due to leakage into the cladding
transparent optical devices affecting the wavefront curvature of light
a technique for acquiring 3D images with laser pulses
electromagnetic radiation in the visible spectral range, or sometimes in an extended spectral region
light which propagates essentially in one direction and has a limited spatial extension in directions perpendicular to its beam direction
forces associated with absorption, reflection or scattering of light
flashes of light
semiconductor diodes that emit light via electroluminescence
width of the spectrum of a light beam or an absorption feature
a parameter quantifying the amplitude–phase coupling in a laser
displays based on liquid crystal modulators
optical modulators which are based on liquid crystals
optical lenses held close to the eye which are used for viewing objects with some moderate magnification
the lifetime of the population in the lower laser level in the absence of radiation
linearly polarized modes of optical fibers with radially symmetric index profiles in the approximation of weak guidance
luminous flux per unit solid angle and unit projected area
light emission which is not caused by heating
radiant flux (among other meanings)
functions describing the spectral sensitivity of the human eye
luminous efficacy and efficiency
the luminous flux of a light source divided by its the radiant power or its electrical consumption (efficacy); the ratio of reached efficacy to the theoretically possible efficacy (luminous efficiency)
a measure of the perceived power of light, e.g. from a light source
luminous flux per unit solid angle
optical filter devices based on birefringence, exhibiting a wavelength-dependent transmission
M
a parameter for quantifying the beam quality of laser beams
the enlargements of images
optical lenses held above objects for viewing them with some moderate magnification
a single-frequency laser used for injection locking one or several other lasers
master oscillator fiber amplifier
a laser system containing a fiber amplifier for boosting the output power
master oscillator power amplifier
a laser system consisting of a seed laser and a laser amplifier for boosting the output power
a theory applied to absorption and emission properties of laser gain media, in particular to solid-state media
permanent or semi-permanent connections of optical fibers which are held in place with mechanical means
laser systems used for medical applications
metal vapor lamps based on light emission from mercury (Hg) atoms
gas discharge lamps containing metal halides
light sources which are based on an electrical discharge in a metal vapor
gas lasers utilizing a metal vapor as gain medium
mirrors where the reflection is obtained from a metal coating
metal–semiconductor–metal photodetectors
fast photodetector devices based on metal–semiconductor (Schottky) contacts
excited states (particularly electronic states in laser gain media) which have a relatively long lifetime due to slow radiative and non-radiative decay
an interferometer with two separate arms and a single beam splitter
the field of optics dealing with particularly small optical components
microscopic bends of optical fibers
electron amplifiers with many spatial channels
solid-state lasers with a quasi-monolithic setup
one- or two-dimensional arrays of microlenses, used e.g. in Shack-Hartmann wavefront sensors
optical lenses of particularly small diameter, e.g. below 1 mm
the optical component of a microscope which is next to the observed object
instruments for seeing very small objects
optical fibers for use with mid-infrared light
light sources emitting mid-infrared radiation in the form of a laser-like beam
spectrometers which can analyze mid-infrared light
lasers with particularly small geometric dimensions
substrates on which coatings for laser mirrors can be deposited
devices which reflect light
the maximum optical bandwidth (limited by intermodal dispersion) which can be used in a telecom fiber
optical cavities used as filters for improving the beam quality of laser beams
devices which can improve the beam quality of laser beams
the phenomenon that different resonator modes experience laser amplification in the same gain medium, leading to cross-saturation effects
a concept for describing and calculating light propagation in certain situations, e.g. involving nonlinear interactions
a multiplexing technique for data transmission in fibers, where different fiber modes are used for different channels
optical devices which allow for efficient coupling between modes of different sizes
the phenomenon that a laser exhibits sudden jumps of optical frequency, which are associated with transitions between different modes of its resonator
a group of techniques for generating ultrashort pulses in lasers
devices for achieving mode locking of a laser
the precise spatial matching of the electric field distributions of laser beams and resonator modes or waveguide modes
a measure of the transverse extent of a laser mode or laser beam
diode lasers which are actively, passively or hybrid mode-locked for generating ultrashort pulses
ultrafast fiber lasers which are actively or passively mode-locked for generating ultrashort pulses
lasers which emit ultrashort pulses on the basis of the technique of mode locking
self-consistent electric field distributions in waveguides, optical resonators or in free space
a mode of operation such as continuous-wave operation, Q-switched or mode-locked operation
a relative modulation amplitude, or (for a saturable absorber) the maximum change in absorption
a nonlinear optical effect which amplifies modulations of optical power
gas lasers where the laser-active gas consists of molecules rather than separate atoms or ions
light with a single optical frequency
optical devices which transmit only light in an adjustable small range of optical wavelengths
solid-state lasers where the whole laser resonator consists only of one piece of crystal or glass
optical fibers containing more than one fiber core
laser sources emitting radiation on multiple laser lines
transitions between electronic levels of atoms or ions in solid media, involving the emission of multiple phonons
light beams in free space or in transparent media which involve multiple (often many) modes, frequently with highly random characteristics
fibers supporting more than one guided mode per polarization direction
an amplifier with multiple passes through the gain medium
a cell which allows to realize multiple passes of a laser beam through a gas
absorption processes involving multiple phonons
absorption processes where multiple photons are absorbed simultaneously
imaging which provides images with multiple spectral channels
N
optical fibers with transverse dimensions below one micrometer
lasers emitting optical pulses with nanosecond durations
single-frequency lasers with a narrow optical emission spectrum
the optical field either close to a source or object or far from it
neodymium-doped laser gain media
laser gain media containing laser-active neodymium ions
optical attenuators with an approximately constant attenuation in a substantial wavelength range
instruments which allow viewing or imaging under conditions of very low light levels
points of an optical system for which an incoming ray, directed at a nodal point, leaves the system with the same direction.
devices for reducing the intensity noise of an optical beam by automatically adjusting the degree of power attenuation
a measure of the excess noise added in an amplifier
specifications for the noise properties of lasers, for example
the input power to a detector which produces the same signal output power as the internal noise of the device
transitions between energy levels of atoms or ions which are not associated with the emission of light
light with properties which can be explained only within quantum optics
a technique of phase matching which does not require a critical angular adjustment
absorption where the absorption coefficient depends on the optical intensity
crystal materials exhibiting an optical nonlinearity, usually of <$\chi^{(2)}$> type
nonlinear frequency conversion
the conversion of input light to light of other frequencies, using optical nonlinearities
a parameter for quantifying the Kerr nonlinearity of a medium
the propagation distance in a medium over which nonlinear effects become substantial
the part of optics dealing with optical nonlinearities and their applications
the part of the light-induced electric polarization which depends nonlinearly on the electric field of the light
nonlinear polarization rotation
the phenomenon that the change in the polarization direction of light in a fiber can depend on the optical intensity
distortion of the spatial, temporal or spectral characteristics of an optical pulse, resulting from optical nonlinearities
optical phenomena involving a nonlinear response to a driving light field
a type of monolithic single-frequency lasers, based on a nonplanar ring resonator
the sine of the acceptance angle of an optical system or a waveguide
O
mathematical spaces for the description of optical elements and systems
optical elements for collecting light from inspected objects, or for sending light to objects
lenses or lens systems as used in telescopes and microscopes, for example, close to the observing eye
laser modules made for integration into larger devices by another manufacturer
the property of a substance or an object not to transmit light or at least to attenuate it
degradations of optical images caused in imaging instruments
the ability of a transparent substance to exhibit polarization rotation or circular dichroism
specialty adhesives for use in optical systems, usually with high transparency for light
devices for amplifying the power of light beams
structures which limit the propagation of light
devices which can reduce the optical power e.g. of a light beam
portable platforms for optical prototyping and for mounting modules on optical tables
devices for periodically interrupting light beams
time measurement devices based on optical frequency standards
devices which can phase-coherently relate optical frequencies to microwave frequencies
an optical imaging technique where longitudinal resolution is achieved based on interference effects with low-coherence light
a close and clean contact between two solids where light can be transmitted without significant wavefront distortions
a method of generating an optical contact by directly (without a contact agent) merging two surfaces of transparent solids with very high surface quality
crystals for optical applications, usually single crystals, often with polished end faces
the transmission of information using light beams, e.g. in fibers
an optical setup which is used to introduce a time delay for a light beam
a logarithmic measure of the power attenuation, or the refractive index
strongly curved optical windows
instruments for measuring optical pulse energies
the fabrication of optical components like lenses, prisms and mirrors
the technology of transmitting information through optical fibers
devices with a wavelength-dependent transmission or reflectance
plates with one or two surfaces of very high optical quality and flatness
the oscillation frequency of the electric field of light
devices which convert light to other light with optical frequencies which are integer multiples of the original frequency
frequency standards using optical transitions in atoms, ions or molecules
glasses of high quality, made for optical applications
a sensitive method of photodetection, reaching the standard quantum limit even for weak signal powers
optical power per unit area
devices which transmit light in one direction but not in the opposite direction
materials used for optical components
the science and technology of performing measurements with light
devices allowing one to manipulate properties of light beams, such as the optical power or phase
an arrangement of laser beams used for cooling atoms or ions
optical amplifiers based on parametric nonlinear interactions
optical parametric chirped-pulse amplification
parametric amplification of chirped ultrashort pulses
light sources based on parametric amplifiers with no signal or idler input
optical parametric oscillators
coherent light sources based on parametric amplification within an optical resonator
product of physical path length and refractive index
the phase of the electric field of an optical wave, usually considered in the time domain
the study of the fundamental physics aspects of optics
the energy per unit time, e.g. transported by a laser beam, or a focusing power
instruments for optical power measurements, based e.g. on heating of an absorber structure or a photodiode
devices for monitoring optical powers in free-space light beams or in optical fibers
optical non-contact instruments for precisely measuring surface profiles
electronically exciting a medium with light, or specifically populating certain electronic levels
a nonlinear process where an optical field generates a quasi-DC nonlinear polarization
a technique for cooling macroscopic samples via laser-induced fluorescence
arrangements of optical components which allow a beam of light to circulate
a technique of sampling signals using laser light, often in the form of ultrashort pulses
sensors based on optical principles, or sensors for light
narrow openings through which light can be transmitted
the decomposition of the power or energy of light according to different wavelengths or optical frequencies
instruments for measuring optical spectra
sensors for mechanical strain based on optical technology, e.g. with fiber Bragg gratings
platforms for building optical devices with suppression of vibrations
temperature sensors based on optical technology, e.g. with fiber Bragg gratings
a measure either for the absorption or the effective optical path length of a sample
optical time-domain reflectometers
instruments for measuring the spatially resolved reflectivities and losses in optical fibers
arrangements for capturing and moving particles with laser beams
flat transparent plates with optical quality, used for protection against the environment
the science and technology dealing with the properties and the propagation of light
optoelectronic devices for signal transmission with electrical isolation between two electrical circuits
mechanical elements used in optics
the technology of electronic devices that interact with light
orientation-patterned semiconductors
semiconductors containing a periodic pattern of domain orientation
a device producing an oscillation – in contrast to an amplifier, for example
partially transparent laser mirrors, used for extracting output beams from laser resonators
a factor influencing the power efficiency of a laser, taking into account intracavity losses
P
mirrors with the surface shape of a paraboloid, or at least a parabolic cross-section
pulses with a parabolic intensity profile
a process of optical amplification based on a parametric nonlinearity
emission of light by a parametric amplifier without signal or input inputs
instantaneous optical nonlinearities based on the <$\chi^{(2)}$> or <$\chi^{(3)}$> nonlinear tensor of a transparent medium
unwanted laser operation in a laser or amplifier device
a frequently used approximation, essentially assuming small angular deviations of the propagation directions from some beam axis
optical fibers without laser-active dopants in the fiber core
a technique of mode locking, based on a saturable absorber inside the laser resonator
maximum optical power of a pulse
a technique for achieving quasi-phase matching of nonlinear interactions in a transparent crystal material
transparent plates for modifying the phase profile of light
a group of techniques for achieving efficient nonlinear interactions in a medium
devices for manipulating the phase of a laser beam
noise of the optical phase of a beam or of an electric signal
phase shift method for distance measurements
a method for optical distance measurements
the velocity with which phase fronts propagate in a medium
the width of an optical frequency range in which some process (e.g. a nonlinear interaction) can be efficient due to sufficiently precise phase matching
quantized microscopic vibrations in solid media
certain glasses from which certain optical fibers and laser gain media can be made, for example
a luminescence which lasts for a relatively long time after excitation of a medium
substances which exhibit luminescence, used mostly for illumination and displays
optical instruments for taking photographic images
an electrode where electrons can be released based on the photoelectric effect
optical materials which exhibit increased light absorption when being exposed to light
photodetectors which exhibit a reduction in electrical resistance caused by incoming light
a technique of optical sampling with photoconductive switches
electric switches controlled by light via photo-induced conductivity
an electric current which is induced by incident light in a photodetector
the phenomenon that the optical power losses in a medium can grow when the medium is irradiated with light at certain wavelengths
devices used for the detection of light
typically linear arrays of photodiodes, provided as compact devices
semiconductor devices with a p–n or p–i–n structure for the detection of light
the emission or excitation of electric carriers related to the absorption of light
photodetectors which are based on the external photoelectric effect
objective lenses used for photography
emission of light which is caused by the irradiation of a material with other light
instruments for measuring light properties such as irradiance or illuminance, or optical properties of objects
the science and technology of measuring properties of light related to its perceived brightness for human eyes
photodetection devices based on the photoelectric effect and charge multiplication by secondary emission of electrons
photodetection at low light levels where single photon absorption events are counted
optical fibers where light is guided based on a photonic bandgap effect
specialty optical fibers with a built-in microstructure, in most cases consisting of small air holes in glass
photonic crystal surface-emitting lasers
surface-emitting semiconductor lasers utilizing a 2D photonic crystal structure for forming an in-plane laser resonator
media with special optical properties due to periodic optical nanostructures
integrated circuits with optical functions
nanostructured materials with special optical properties
surfaces containing sub-wavelength structures which lead to special optical properties
the science and technology of light
quanta of light energy
a type of semiconductor-based photodetector with internal current amplification for higher responsivity
gas-filled or vacuum tubes which can be used as photodetectors
semiconductor devices which generate electrical energy from light energy
diode lasers emitting picosecond light pulses
lasers emitting pulses with picosecond durations
circular holes, typically with diameters well below one millimeter
waveguide structures guiding light only in one dimension
waves with plane wavefronts
optical fibers made of polymer materials
optical elements made of organic polymer materials
electronic devices for driving Pockels cells
electro-optic devices, used for building modulators
the phenomenon that the refractive index of a medium exhibits a modification which is proportional to the strength of an applied electric field (linear electro-optic effect)
instruments for measuring the rotation angle of optical polarization caused by optically active substances
a technique for combining two polarized laser beams
the period of interference effects in a birefringent medium
the polarization dependence of the propagation characteristics of light waves in optical fibers
direction of the electric field oscillation of a light beam
patterns of electric (or magnetic) polarization of a medium which are usually caused by light waves
polarization-maintaining fibers
specialty optical fibers with strong built-in birefringence, preserving the properly oriented linear polarization of an input beam
optical filters where the light transmission depends strongly on the direction of polarization
the polishing of fiber ends in order to obtain particularly well-defined optical properties
light with multiple optical frequencies
an optical device which sends light with different wavelengths to different directions
a state of a medium where a higher-lying electronic level has a higher population than a lower-lying level
photodetectors which can detect the position of a light spot in one or two dimensions
intensity or power per unit frequency interval
delivery of power for electronic devices via light in an optical fiber which is converted to electricity
a procedure for substantially increasing the output power of lasers
optical power or noise power per unit frequency interval
a vector indicating the strength and direction of energy flow of an electromagnetic wave
a crude measure for chromatic dispersion of a transparent optical material
principal points and principal planes
planes from which rays appear to be deflected in an optical system according to paraxial optics, and the intersections of those planes with the optical axis
combinations of two prisms, mostly used for dispersion compensation
transparent optical devices which refract or reflect light
a mode- and frequency-dependent quantity describing the propagation of light in a medium or waveguide
losses of optical energy during propagation of light
the measurement of various properties of an optical pulse
linear or nonlinear techniques for reducing the durations of optical pulses
the duration of an optical pulse
energy of an optical pulse
the phenomenon that the arrival time of an ultrashort pulse varies across the beam profile
the generation of light pulses (flashes)
electrically controlled optical switches used for extracting single pulses from a pulse train
working with physical models describing the propagation of ultrashort pulses e.g. in lasers or optical fibers
the number of pulses emitted per second e.g. by a mode-locked or Q-switched laser
devices which can be used to modify the temporal or spectral shape of ultrashort light pulses
devices for temporally stretching ultrashort light pulses
regular sequences of pulses
a method for fabricating thin films on substrates by evaporating materials with laser pulses
lasers emitting light in the form of pulses
the absorption of pump light, e.g. in a laser or a laser amplifier
a part of a lamp-pumped solid-state laser, containing a laser rod, one or more lamps, reflectors, a cooling arrangement and possibly other parts
reduction in the transmitted pump power in a laser or nonlinear conversion device
the ratio of pump power and threshold pump power of a laser
techniques for investigating ultrafast phenomena, where a pump pulse excites a sample and a probe pulse is used for probing the sample after an adjustable delay time
light detectors based on the pyroelectric effect
photodiodes with a p–i–n semiconductor structure
Q
a measure of the damping of resonator modes
optical switches which are typically used for generating nanosecond pulses in lasers
a method for obtaining energetic pulses from lasers by modulating the intracavity losses
lasers which emit optical pulses, relying on the method of Q switching
an operation regime of mode-locked lasers with strong fluctuations of the pulse energy
instabilities of passively mode-locked lasers where the pulse energy is unstable
semiconductor lasers relying on intersubband transitions, normally emitting in the mid-infrared spectral region
methods to encrypt information securely, relying on quantum-mechanical phenomena
energy difference between pump and laser photons
microscopic structures confining charge carriers in three dimensions
percentage of input photons which contribute to a desired effect
an area of physics which is the basis of optoelectronics
methods for the secure distribution of encryption keys
noise arising from quantum fluctuations
the part of optics which deals with quantum effects
the science and technology using quantum optics for applications like quantum communications, quantum computing and quantum metrology
thin layers confining carriers in one dimension
dielectric mirrors based on a sequence of quarter-wave layers
quasi-continuous-wave operation
an operation mode of lasers (e.g. diode bars) where the pump power is switched on for short time intervals in order to limit thermal effects
a technique of achieving a kind of phase matching, using a periodic structure
soliton-like pulses in lasers or fiber-optic links
quasi-three-level laser gain media
laser gain media where the lower laser level has a substantial thermally induced population
the reduction or limitation of an excited-state population, mostly by unwanted effects
R
oscillations of level populations (or quantum mechanical probability amplitudes) under the influence of an incident light field
the optical power per unit area and solid angle
energy of some electromagnetic radiation which is emitted, transmitted or absorbed during some interval of time
radiant flux emitted by a surface per unit area
radiant energy per unit time which is emitted, transmitted, reflected or received by an object
radiant flux per unit solid angle
a mechanical pressure resulting from incident light or other radiation
lasers where the heat generation in the gain medium is compensated by optical refrigeration in the same medium
optical fibers which exhibit relatively little performance degradation when exposed to high-energy gamma or other radiation
lifetime of an electronic state in the (hypothetical) situation where only radiative processes depopulate that level
radio and microwave over fiber
the transmission of radio frequency signals through optical fibers
the science and technology of measuring properties of electromagnetic radiation, including light
optical amplifiers based on Raman gain
optical gain arising from stimulated Raman scattering
nonlinear media in which stimulated Raman scattering can be utilized for obtaining optical amplification
lasers based on Raman gain rather than on laser gain from stimulated emission
a nonlinear scattering process involving optical phonons
optical spectroscopy based on spontaneous or stimulated Raman scattering
optical glass fibers which are doped with rare earth ions
rare-earth-doped laser gain media
laser gain media which are doped with rare earth ions
a method of modeling the dynamics of laser gain media
the distance from a beam waist where the mode radius increased by a factor square root of 2
scattering of light at scattering centers which are much smaller than the wavelength
a spectroscopic method which is often used for obtaining the scaling of emission spectra of laser gain media
fiber loops in which light can circulate many times
a lower limit for the temperature which can be reached with some laser cooling techniques
lasers emitting red light
optical cavities serving as a kind of frequency reference
the ratio of reflected optical power to the incident optical power at some reflecting object
the ratio of reflected optical power to the incident optical power at a surface
instruments for measuring the reflectance of objects
devices which reflect light or other radiation
the change of the propagation direction when a wave comes from one medium into another one
a measure of the reduction in the velocity of light in a medium
scientific instruments used to measure the refractive index of materials
optical amplifiers with a resonator in which a light pulse can do multiple round trips before being coupled out
noise of the optical intensity (or actually power), normalized to its average value
small mutually coupled oscillations of the laser power and laser gain around their steady-state values
frequency doubling with a nonlinear crystal placed in a resonant enhancement cavity
the description of the optical components from which an optical resonator is made, and their exact arrangement
modes (self-reproducing field configurations) of an optical or microwave resonator
photocurrent per unit optical power incident on a photodetector
the difference in optical phase shifts between two polarization directions, e.g. for light transmitted through a sample or reflected at a surface
optical devices which reflect light in a direction which is parallel to the incident beam
a measure for how much reflected light is attenuated
source of red, green and blue light, which is usually provided in the form laser beams
lasers with a ring resonator
optical resonators where light can independently circulate in two different directions
solid-state lasers with a rod-shaped gain medium
cylindrical lenses with the geometrical form of a cylinder
solid-state lasers based on a ruby crystal
dielectric interference filters with a continuous variation of the refractive index
S
light absorbers with a degree of absorption which is reduced at high optical intensities
a special type of saturable semiconductor absorbers
a measure of the incident optical pulse energy required for achieving significant saturation of an absorber or a gain medium
a measure of the incident optical power required for achieving significant saturation of an absorber or a gain medium
lens systems which are designed for use in laser scanners
processes where light is sent in other directions, usually but not always in random directions
linewidth of a single-frequency laser with quantum noise only
lasers which are designed for scientific applications
vision of the human eye at lower and higher light intensity levels, respectively
pulses with a temporal intensity profile which has the shape of a sech2 function
lasers which are used for generating some seed light into an amplifier or another laser
focusing of a beam in a transparent medium, caused by the beam itself through a nonlinear process in the medium
self-heterodyne linewidth measurement
a technique for laser linewidth measurements, based on a beat note between the beam and a delayed version of itself
nonlinear phase modulation of a beam, caused by its own intensity via the Kerr effect
mode locking which is quickly achieved after turning on a laser, without external intervention
a nonlinear effect in pulse propagation, leading to an increasingly steep trailing slope of the temporal pulse shape
self-terminating laser transitions
laser transitions which can not be continuously operated due to the accumulation of population in the lower laser level
an equation for calculating the wavelength-dependent refractive index of a medium
lasers based on semiconductor gain media
semiconductor optical amplifiers
optical amplifiers based on semiconductor gain media
semiconductor saturable absorber mirrors
saturable semiconductor absorber devices acting as nonlinear mirrors
materials with a small band gap energy
(different meanings, depending on the context)
Shack–Hartmann wavefront sensors
wavefront sensors which are based on a microlens array
quantum-limited intensity noise
a technique of pumping a solid-state laser in directions which are approximately transverse to its beam direction
sign conventions in wave optics
conventions concerning the signs of phase terms in wave optics
lamps for displaying or sending light signals
the ratio of signal power to noise power in a detector
optical fibers based on fused silica or related materials
glasses which are based on silica (silicon dioxide) and some additions
photonic technology based on silicon chips
lasers with only a single atom as the gain medium
long and thin rods made of monocrystalline materials
lasers emitting radiation in a single resonator mode
an operation mode of a laser where only a single resonator mode acquires a significant power
optical fibers supporting only a single guided mode per polarization direction
operation of a laser on axial (longitudinal) resonator modes only, or even on a single axial mode
optical fibers which transmit only light with a certain polarization
a mechanism for laser cooling of atoms or ions
solid-state bulk lasers where the gain medium has the form of a slab
a laser which is injection-locked to another laser
differential power efficiency of a laser
optical gain for small signal intensities, where no amplifier saturation occurs
metal vapor lamps based on light emission from sodium (Na) atoms
devices for solar power generation, containing photovoltaic cells
the generation of electricity based on sunlight
photodetectors which are insensitive to visible light but react to ultraviolet light
lasers based on solid-state gain media (usually ion-doped crystals or glasses)
a mechanism for laser mode locking based on soliton pulses
the distance over which higher-order solitons reproduce their temporal and spectral shape
pulses with a certain balance of nonlinear and dispersive effects
a multiplexing technique for optical data transmission where multiple spatial channels are utilized
lasers which have been qualified for use in space missions, where the need to fulfill special conditions
a distortion of the gain shape in a laser medium (or the loss spectrum in a saturable absorber medium), caused by saturation effects of a standing wave
the phenomenon that the intensity distribution of a beam in an anisotropic crystal drifts away from the direction of the wave vector
optical fibers with special designs or materials
a class of methods for beam combining, based on wavelength-sensitive beam combiners
brightness per unit optical bandwidth
imaging which also provides spectral information
low pressure gas discharge lamps emitting light on one or more standard spectral lines
narrow spectral features related to emission or absorption lines of certain substances
the phase of the electric field in the frequency domain
a class of interferometric methods for pulse characterization, where interference in the frequency domain is exploited
quantities in radiometry and photometry which describe the distribution e.g. of a radiant flux over different optical frequencies or wavelengths
spectral response of a photodetector
the range of optical wavelengths for which a photodetector is sensitive
a type of diagrams which visualize optical or other signals
instruments for spectrally analyzing light, based on a polychromator and a multi-channel photodetector
devices for separating spectral components
instruments for measuring the wavelength-dependent transmittance or reflectance of solutions or solid objects
methods where the interaction of light with matter is utilized, e.g. for detecting substances or measuring concentrations
reflection of light where the angle of reflected light equals the angle of incident light, but on the opposite side of the surface normal
optical aberrations resulting from spherical optical surfaces
the tendency of some lasers to emit spikes of output power, particularly after being switched on
a quantum effect, causing the spontaneous decay of excited states of atoms or ions
fibers which have been twisted during the fiber drawing process in order to obtain modified polarization properties
nonclassical states of light with noise below the standard quantum limit in one quadrature component
stability zones of optical resonators
parameter regions of an optical resonator where the resonator is geometrically stable
measures applied to lasers in order to improve their stability in terms of output power, optical frequency, or other quantities
a limit for noise levels set by quantum mechanics
spectral lines which are often used as wavelength references
optical resonators with two end mirrors
groups of energy levels (e.g. of laser gain media) which can have slightly different energies due to the Stark effect
optical fibers with a step-index refractive index profile
a quantum effect, where photon emission is triggered by other photons
the reduction in photon energy in certain processes
devices for measuring the power of an optical pulse versus time
sum and difference frequency generation
nonlinear processes generating beams with the sum or difference of the frequencies of the input beams
a nonlinear process for strong spectral broadening of light
collective emission of radiation by an ensemble of excited atoms or ions
transport of some quantity with a velocity exceeding that of light in vacuum
fluorescence which is enhanced by laser amplification
broadband semiconductor light sources based on superluminescence
optical sources based on superluminescence
laser mirrors with a very high reflectivity
collective emission of an ensemble of atoms or ions after coherent excitation
surface-emitting semiconductor lasers
semiconductor lasers where the generated light propagates in the direction perpendicular to the wafer surface
the synchronization of light pulses generated with lasers
pumping of a laser or an optical parametric oscillator with short light pulses in synchronism with the emitted pulses
T
optical amplifiers which contain a tapered section, where the beam area is gradually increased
optical fibers which are over some length stretched out to a very small diameter
laser diodes containing a tapered region for achieving a higher beam quality
lenses or objectives having the entrance or exit pupil at infinity
optical fibers for use in optical fiber communications
optical instruments for viewing distant objects, or sometimes more generally afocal systems
the loss of temporal overlap of pulses, caused by group velocity mismatch
detectors for terahertz radiation
electromagnetic radiation with frequencies around 0.1 THz to 10 THz
sources of electromagnetic radiation with frequencies around 0.1 THz to 10 THz
thermally caused distortion and deflection of a laser beam profile for propagation through a gas or liquid with high optical power
light detectors which are based on measuring light-induced temperature rises
imaging based on thermal radiation
a lensing effect induced by temperature gradients
electromagnetic radiation which results from thermal emission
solid-state bulk lasers having a very thin disk of laser-active material as the gain medium
optical polarizers based on a multilayer dielectric coating
chromatic dispersion related to a third-order dependence of the phase change on the frequency offset
the pump power at which the laser threshold is reached
lasers with a threshold power which is virtually zero
thulium-doped laser gain media
laser gain media containing laser-active thulium ions
a multiplexing technique operating in the time domain
distance measurements based on measuring the time of flight of a light pulse
spectroscopy where time-dependent signals are measured
product of temporal and spectral width of a pulse
fluctuations of the temporal positions of pulses
a phase reflecting timing deviations by relating them to the pulse period
lasers based on a Ti:sapphire gain medium
the phenomenon that light incident on the boundary between two transparent media is fully reflected if the light is coming from the optical more dense medium and the angle of incidence is sufficiently large
a limit for the time–bandwidth product of an optical pulse
material parameters for quantifying the likelihood or rate of optical transition events
transition-metal-doped laser gain media
laser gain media which are doped with transition metal ions
diffraction gratings which are used in transmission
the ratio of transmitted optical power to the incident optical power at a surface
the ratio of transmitted optical power to the incident optical power at some partial transparent object
a method for distance measurements
optical fibers having three claddings
lasers the output wavelengths of which can be tuned
optical filters with tunable filter parameters, e.g. concerning center wavelength of pass band
solid-state lasers based on tungstate crystals as gain media
a technique for achieving single-frequency operation of a laser, based on quarter-wave plates on both sides of the gain medium
a nonlinear absorption process where two photons are simultaneously absorbed
an interferometer similar to a Michelson interferometer, but with expanded beams
U
amplifiers for ultrashort (femtosecond or picosecond) optical pulses
the area of laser physics dealing with ultrashort processes
lasers emitting ultrashort pulses
the part of optics dealing with ultrafast phenomena
optical pulses with durations of picoseconds or less
lasers (or other laser-based light sources) generating ultraviolet light
invisible light with wavelengths shorter than ≈ 400 nm
optical elements for use with ultraviolet light
optical resonators which are dynamically unstable with respect to transverse beam offsets
a process where light can be emitted with photon energies higher than those of the light generating the excitation
lasers relying on upconversion processes
the lifetime of the population in the upper laser level
V
a normalized frequency parameter, which determines the number of modes of a step-index fiber
quantum noise of the vacuum state, or quantum noise introduced into an optical system via a vacuum input
lasers based on rare-earth-doped yttrium, gadolinium or lutetium vanadate crystals, usually Nd:YVO4
optical attenuators with a variable degree of attenuation
mirrors with a spatial variation of the reflectivity (reflectance)
arrays containing many VCSEL laser emitters
the velocity with which light propagates in a medium
velocity-matched photodetectors
a type of photodetector where propagation velocities of light and electrical signals are matched in order to achieve a very high detection bandwidth
vertical cavity surface-emitting lasers
a monolithic kind of semiconductor lasers with beam emission perpendicular to the wafer surface
vertical external-cavity surface-emitting lasers
surface-emitting semiconductor lasers with an external laser resonator
lasers based on gain media with a large gain bandwidth, caused by a strong interaction of electronic transitions with phonons
a reduction of image brightness in peripheral regions
lasers (or other laser-based light sources) emitting visible light
Bragg gratings written into some bulk material
W
total electrical-to-optical power efficiency of a laser system
the description of optical phenomena based on wave models
a vector indicating the direction of wave propagation and the phase delay per unit length
surfaces connecting points with the same phase of a wave
chromatic dispersion arising from waveguiding effects
lasers with a waveguide structure in the gain medium
spatially inhomogeneous transparent structures for guiding light
the spatial period of a plane wave
wavelength division multiplexing
a multiplexing technique working in the wavelength domain
the manipulation of the output wavelength of an optical device such as a laser or an optical parametric oscillator
lasers which allow for period and fast wavelength tuning
wavelength-tunable light sources
light sources where the optical wavelength can be tuned
devices for precise measurements of laser wavelengths
the phase delay per unit length, or that quantity divided by <$2\pi$>
transparent plates with a defined amount of birefringence, used for modifying the polarization of light
prisms with a small angle between the end surfaces
light which creates a white color impression
interferometers using broadband light inputs
light sources with very broad optical bandwidth
the distance between an objective and the object
X
lasers emitting in the X-ray spectral region
lamps based on an electrical discharge in xenon gas
Y
lasers based on YAG (yttrium aluminum garnet) crystals, usually Nd:YAG or Yb:YAG
lasers emitting yellow or orange light
lasers based on YLF (yttrium lithium fluoride) crystals, usually Nd:YLF
ytterbium-doped laser gain media
laser gain media containing laser-active ytterbium ions
Z
a technique for measuring the strength of the Kerr nonlinearity of a material, relying on self-focusing
a wavelength where the group velocity dispersion of a fiber or a material is zero
an optical device for focusing light (or other electromagnetic radiation) based on diffraction
List of Formula Symbols
| Symbol | Explanation | SI Units |
|---|---|---|
| <$a$>, <$r_\text{co}$> | core radius of a fiber | m |
| <$b$> | confocal parameter of a laser beam (twice the Rayleigh length) | m |
| <$c$> | velocity of light | m/s |
| <$d_\textrm{eff}$> | effective nonlinear coefficient of a nonlinear crystal material | m/V |
| <$D_2$> | group delay dispersion | s2 |
| <$D_{2\lambda}$> | group delay dispersion with wavelength derivative | s/m |
| <$D_3$> | third-order dispersion | s3 |
| <$d_{ij}$> | components of the <$\chi^{(2)}$> nonlinear tensor | m/V |
| <$e$> | elementary electric charge | C |
| <$f$> | focal length (e.g., of a lens) | m |
| <$f$> | noise frequency | Hz |
| <$f_\textrm{rep}$> | pulse repetition rate | Hz |
| <$f_\textrm{ro}$> | relaxation oscillation frequency | Hz |
| <$g$> | gain coefficient | 1 or m−1 |
| <$g(\tau )$> | complex degree of coherence | 1 |
| <$g_\textrm{B}$> | nonlinear gain coefficient for Brillouin scattering | m/W |
| <$g_\textrm{R}$> | nonlinear gain coefficient for Raman scattering | m/W |
| <$g_\textrm{ss}$> | small-signal gain coefficient | 1 or m−1 |
| <$h$> | Planck's constant | J s |
| <$k$> | wavenumber | m−1 |
| <$k_\textrm{B}$> | Boltzmann constant | J/K |
| <$\Delta k$> | phase mismatch of a parametric nonlinear process | rad/m |
| <$l_\textrm{rt}$> | round-trip losses of a resonator | 1 |
| <$n$> | refractive index | 1 |
| <$n_\textrm{e}$> | extraordinary refractive index | 1 |
| <$n_\textrm{eff}$> | effective refractive index | 1 |
| <$n_\textrm{g}$> | group index | 1 |
| <$n_\textrm{o}$> | ordinary refractive index | 1 |
| <$n_2$> | nonlinear index | m2/W |
| <$Q$> | Q factor | m |
| <$q$> | complex <$q$> parameter (→ Gaussian beams) | m |
| <$r$> | radius (e.g., in fiber core or distance from beam axis) | m |
| <$r$> | pump parameter of a laser | 1 |
| <$r_{ij}$> | components of the electro-optic tensor | m/V |
| <$v_\textrm{g}$> | group velocity | m/s |
| <$v_\textrm{p}$> | phase velocity | m/s |
| <$w$> | Gaussian beam radius | m |
| <$w_0$> | beam radius at the beam waist | 1 |
| <$z_\textrm{R}$> | Rayleigh length | m |
| <$z_\textrm{s}$> | soliton period | m |
| <$A$> | amplitude of pulse envelope | |
| <$A_\textrm{eff}$> | effective mode area | m2 |
| <$B$> | B integral | rad |
| <$B$> | noise bandwidth | Hz |
| <$B$> | brightness | W/(m2 rad2) |
| <$\textrm{BPP}$> | beam parameter product | mm mrad |
| <$D_{\lambda }$> | dispersion parameter | ps/(nm km) |
| <$E$> | electric field strength | V/m |
| <$E_\textrm{p}$> | pulse energy | J |
| <$E_\textrm{sat}$> | saturation energy | J |
| <$F$> | finesse | 1 |
| <$F$> | noise figure | 1 |
| <$F_\textrm{sat}$> | saturation fluence | J/m2 |
| <$G_X(\tau )$> | autocorrelation function of some variable <$X$> | |
| <$I$> | optical intensity | W/m2 |
| <$I_\textrm{sat}$> | saturation intensity | W/m2 |
| <$L_\textrm{coh}$> | coherence length | m |
| <$M^2$> | _M_2 factor | 1 |
| <$N_\textrm{F}$> | Fresnel number | 1 |
| <$N_\textrm{dop}$> | doping concentration | m−3 |
| <$\textrm{NA}$> | numerical aperture | 1 |
| <$P$> | optical power | W |
| <$P$> | electric polarization of a medium | C/m2 |
| <$P_\textrm{out}$> | output power | W |
| <$P_\textrm{p}$> | peak power of a pulse | W |
| <$P_\textrm{sat}$> | saturation power of a laser gain medium or saturable absorber | W |
| <$Q$> | Q factor | 1 |
| <$R$> | power reflectivity (or reflectance) (of a mirror) | 1 |
| <$R$> | radius of curvature (e.g., of wavefronts) | m |
| <$R$> | responsivity of a photodiode | A/W |
| <$\Delta R$> | modulation depth of a saturable absorber | 1 |
| <$S_{\varphi }(f)$> | power spectral density of a phase value | rad2/Hz |
| <$T$> | temperature | K or °C |
| <$T_\textrm{g}$> | group delay | s |
| <$T_\textrm{oc}$> | output coupler transmission | 1 |
| <$T_\textrm{rt}$> | round-trip time of an optical resonator | s |
| <$V$> | V number of a step-index fiber | 1 |
| <$\alpha$> | absorption coefficient | m−1 |
| <$\alpha$> | linewidth enhancement factor | 1 |
| <$\alpha$> | thermal expansion coefficient | K−1 |
| <$\beta$> | propagation constant | rad/m |
| <$\beta_2$> | group velocity dispersion | s2/m |
| <$\gamma_\textrm{SPM}$> | self-phase modulation coefficient | rad/(W m) |
| <$\epsilon_0$> | electric permittivity of vacuum | C/Vm |
| <$\epsilon$> | relative electric permittivity | 1 |
| <$\eta$> | efficiency | 1 |
| <$\eta_\textrm{oc}$> | output coupling efficiency | 1 |
| <$\theta$> | beam divergence half-angle | rad |
| <$\theta$> | polar angle | rad |
| <$\kappa$> | thermal conductivity | W/(m K) |
| <$\Lambda$> | optical path length | m |
| <$\lambda$> | optical wavelength | m |
| <$\lambda_\textrm{p}$> | pump wavelength | m |
| <$\lambda_\textrm{s}$> | signal wavelength | m |
| <$\mu$> | relative magnetic permeability | 1 |
| <$\mu_0$> | magnetic permeability of vacuum | N/A2 |
| <$\nu$> | optical frequency | Hz |
| <$\nu_\textrm{B}$> | Brillouin frequency shift | Hz |
| <$\nu_\textrm{ceo}$> | carrier–envelope offset frequency | Hz |
| <$\nu (t)$> | instantaneous frequency | Hz |
| <$\Delta \nu$> | optical bandwidth | Hz |
| <$\rho$> | walk-off angle | rad |
| <$\sigma_\textrm{abs}$> | absorption cross-section | m2 |
| <$\sigma_\textrm{em}$> | emission cross-section | m2 |
| <$\tau_2$> | upper-state lifetime | s |
| <$\tau_\textrm{coh}$> | coherence time | s |
| <$\tau_\textrm{p}$> | pulse duration | s |
| <$\tau_\textrm{rad}$> | radiative lifetime | s |
| <$\varphi$> | azimuth angle | rad |
| <$\varphi$> | optical phase or phase shift | rad |
| <$\varphi_\textrm{G}$> | Gouy phase shift | rad |
| <$\varphi_\textrm{nl}$> | nonlinear phase shift from the Kerr effect | rad |
| <$\varphi_\textrm{t}$> | timing phase | rad |
| <$\Delta \varphi_\textrm{ceo}$> | carrier–envelope offset phase | rad |
| <$\chi^{(2)}$>, <$\chi^{(3)}$> | nonlinear tensor | 1 |
| <$\omega$> | angular frequency | rad/s, s−1 |
| <$\Lambda$> | modulation period of a fiber Bragg grating | m |