The RP Photonics Encyclopedia - trusted content on laser technology, fiber optics, nonlinear optics and other topics of photonics (original) (raw)
The Photonics Spotlight is a “blog” which highlights interesting news and useful information in the area of photonics, particularly laser technology and applications.
2025-11-03: Lost factors of 2 around Gaussian beams, peak intensities, damage thresholds, and effective mode areas
2025-09-30: Concept Trees for the RP Photonics Encyclopedia
2025-08-25: Photon Counting Terminology: Are We Really Counting?
2025-08-18: Do Photons Have an Optical Phase?
2025-07-30: More on the question: Can monochromatic light be unpolarized?
2025-04-01: Have AI bots like ChatGPT Got Better on Photonics Questions?
2025-02-27: Tools from RP Photonics for Responsible Purchasing
2025-02-07: New AI-based Features on the RP Photonics Website
2024-04-23: How Responsible Purchase Decisions for Expensive Goods Like Lasers Are Done
2024-04-08: New Case Studies Complement the RP Photonics Encyclopedia
2023-11-20: Using the Cited By Feature of Crossref
2023-11-16: Citing Encyclopedia Articles
2023-09-06: Can AI bots like ChatGPT and Bard Answer Photonics Questions?
2023-05-25: The RP Photonics Website Got a New Technical Basis
2023-01-24: Launching Light into Step-Index Multimode Fibers
2022-08-04: Encyclopedia Articles on Laser Material Processing
2021-06-29: 1000 Articles in the RP Photonics Encyclopedia
2021-04-30: Wavelength or Optical Frequency, What Is the Better Specification?
2021-03-08: Luminance — a Term which is Worth Some Thoughts
2021-01-06: Improvements of the RP Photonics Website
2020-09-30: Beam Radius and Beam Quality of Laser Pulses
2020-09-18: New Information Channel of RP Photonics: the RP Photonics Marketing News
2020-07-08: Time to Start Digital Marketing with RP Photonics — with a Discount
2020-05-11: Digital and Interactive Methods of Supporting the Photonics Industry
2020-04-01: Photonics Marketing in Times of the Coronavirus Crisis
2020-03-16: Laser Physics Helps to Understand the Corona Virus Crisis
2020-01-20: News on the RP Photonics Website
2019-11-19: Why Are Large Mode Areas Problematic?
2019-08-26: Can Monochromatic Light be Unpolarized?
2019-03-01: New Articles in the RP Photonics Encyclopedia
2018-09-28: Resonator Modes in Microchip Lasers
2018-08-22: What is Different for Quasi-Three-Level Lasers?
2018-07-16: Thoughts on Thermal Lensing
2018-06-08: Understanding Intensity Noise
2018-05-11: Gain Saturation in Solid-state Lasers
2018-04-06: Laser Physics: the Essential Roles of Phonons in Solid-state Lasers
2018-03-05: Dependence on Raman Conversion on the Optical Bandwidth
2018-01-08: Self-starting of Passively Mode-locked Lasers
2017-12-04: Energy Levels of Solid-state Gain Media
2017-11-02: Gaussian Apertures in Resonator Models: Not Only for Exotic Lasers, But Also for Gain Guiding
2017-10-03: Importance of Spectral Wings on the Pulse Duration
2017-08-31: Passive Mode Locking with Slow Saturable Absorbers: Surprisingly Stable!
2017-08-01: Fiber Amplifiers: Modeling of Ultrashort Pulse Amplification with Saturation of Wavelength-dependent Gain
2017-04-12: Does a Saturable Absorber in a Laser Lead to Passive Q-switching or Mode Locking?
2017-03-15: Interesting Features of Over-long Fiber Lasers
2017-02-17: Photonics in Times of Trouble for International Trade
2017-01-27: Second Opinion: a Useful Tool, also in Laser Technology!
2016-12-13: Nonlinear Input–Output Curves for Lasers
2016-10-27: Challenges for Nonlinear Frequency Conversion in Extreme Wavelength Regions
2016-09-12: An Apparent Paradox Concerning Light Beams in Fibers
2016-08-11: Mode Coupling in Optical Fibers: Selective Excitation of a Higher-order Mode with a Fiber Bragg Grating
2016-07-05: The Round-trip Phase Shift in an Optical Resonator
2016-06-08: Citations in the Encyclopedia of Laser Physics and Technology
2016-05-12: Measurement of Absorption Spectra of Active Fibers: Not as Easy as One Might Think!
2016-04-04: Photographs, Drawings and Videos for the Encyclopedia of Laser Physics and Technology
2016-02-26: New Encyclopedia Articles
2016-01-27: Finding Suppliers for Photonics Products
2015-11-28: How to Store Light – and to Understand the Laser Principle
2015-10-17: The Linewidth of Single-frequency Lasers
2015-09-24: Q-switched Lasers: Nd:YVO4 Better Suited than Nd:YAG for High Pulse Repetition Rates
2015-08-08: Gain Saturation with Pulses
2015-07-01: Self-phase Modulation Causes Spectral Broadening – Does it Really?
2015-05-14: Alignment Sensitivity of Laser Resonators – an Important Design Criterion
2015-04-10: The Enormous Popularity of the RP Photonics Website
2015-03-11: Strange Time Dependence of ASE from a Fiber Amplifier
2015-02-05: Attenuating Laser Beams – not That Easy
2015-01-09: New Tutorial: Modeling of Fiber Amplifiers and Lasers
2014-12-17: How Ph.D. Students Should Get Supported by Supervisors
2014-11-14: Correctly Designing Frequency Conversion Stages: Not Easy, but Worthwhile!
2014-10-03: Fiber Optics Tutorials
2014-07-28: How to Define the Mode Radius of a Fiber?
2014-06-27: Shortages of Rare Earth Materials – a Problem for Photonics?
2014-05-16: 10-Year Anniversary of RP Photonics
2014-04-02: Lower Emission Cross-section Leads to Higher Pulse Energy?!?
2014-01-17: Mediation in Disputes on Laser Technology
2013-12-13: Avoiding Trouble with Laser Specifications
2013-11-12: Beam Quality Limit for Multimode Fibers
2013-08-26: Frequency Doubling and the Reverse Process
2013-07-08: Amplified Spontaneous Emission in Fiber Amplifiers
2013-06-13: Two New Photonics Newsletters
2012-08-06: The New RP Photonics Buyer's Guide
2012-03-12: New Raman Lasers
2012-03-03: Conflicting Definitions of s and p Polarization
2012-02-03: Simulation Software: Use Commercial Products or Home-Made Software?
2011-12-23: Kerr-lens Mode-locked Thin-disk Laser
2011-06-10: Are Compact Resonators More Stable?
2011-05-28: Explanation for the Mode Instability in High-power Fiber Amplifiers with Few-mode Fibers
2011-03-13: What if Solid-State Laser Transitions Were Much Stronger?
2011-02-10: Fiber Lasers: More Difficult to Design than Bulk Lasers
2011-01-05: Femtosecond Fiber Amplifiers: Unlimited Peak Power?
2010-09-02: Why LEDs are Energy-efficient, and Why They Can Increase Energy Consumption
2010-07-27: Special SESAMs for Mode-locked High-power Lasers?
2010-07-12: Laser Development: Get an Expert Early on!
2010-06-09: Poor Man's Isolator
2010-05-14: Plagiarism, Exploiting the Encyclopedia of Laser Physics and Technology
2010-04-26: Resolution and Accuracy of Measurements
2010-04-16: Why Large Mode Area Waveguides Do Not Work for Laser Diodes
2010-04-08: Creating a Top-hat Laser Beam Focus
2010-03-22: All-in-one Concepts versus Modular Concepts
2010-03-15: Spatial Walk-off and Beam Quality in Nonlinear Frequency Conversion
2010-03-09: Nonlinearities in Fiber Amplifier Modeling
2010-03-03: Thresholds for Nonlinear Effects in Fiber Amplifiers
2010-02-26: New Scientific Paper: Timing Jitter and Phase Noise of Mode-locked Fiber Lasers
2010-02-06: Scientific Conferences and Publications: Emphasize Device Performance or Insight?
2010-01-29: Far From Maturity: The Photonics Industry
2010-01-22: Pumping Fiber Lasers with Fiber Lasers
2010-01-11: Beams of Laser Pointers: Visible in Air?
2009-12-31: Tilt Tuning of Etalons
2009-12-13: Johnson–Nyquist Noise in Photodiode Circuits
2009-12-08: Increased Output Power of a Laser with Forced Tuning
2009-11-22: The Beam Focus – Not Just a Demagnified Version of Your Beam
2009-11-18: Articles and a Quiz on Photonics Issues
2009-11-13: Photodetection: Optical and Electrical Powers
2009-11-03: Coherent Light from a Bulb?
2009-10-19: Risk Factors for Science Fraud and the Scientist's Responsibility
2009-10-12: Cold Light from the Hottest Bodies and from Cool Devices
2009-10-08: Nobel Prize for Charles K. Kao for Pioneering Work on Optical Fibers
2009-10-03: Peak Intensity of Gaussian Beam
2009-09-27: Lasers with Short Upper-state Lifetime
2009-09-19: Are Laser Resonators Power Scalable?
2009-09-07: Anniversary: 5 Years of the Encyclopedia of Laser Physics and Technology
2009-09-01: Fresnel Reflections from Double Interfaces
2009-08-22: Jitter and Phase Noise of Mode-locked Fiber Lasers
2009-08-14: Progress on Green Laser Diodes
2009-08-12: What is an Optical Transistor?
2009-07-29: No Beat Note for Orthogonal Modes
2009-07-23: Submit Photographs for the Encyclopedia of Laser Physics and Technology
2009-07-21: Signal-to-Noise Ratio and Measurement Bandwidth
2009-07-09: Gain-guiding Index-antiguiding Fibers
2009-06-29: Doing Things Properly: It's the Economy, Stupid!
2009-06-23: Coherence – a Black-or-White Issue?
2009-06-08: Prizes of the European Physical Society
2009-06-02: 5 Years of RP Photonics
2009-05-22: Interference Effects with Imbalanced Intensity Levels
2009-05-13: The Minimum Time–Bandwidth Product
2009-04-28: SPIE Field Guides
2009-04-19: Last Chance to Get the Encyclopedia of Laser Physics and Technology Cheaper
2009-04-17: Miniature Laser Projectors – The Next Big Laser Thing?
2009-04-06: Laser Pointers in Soccer Games: Not Necessarily Harmless
2009-04-05: Stability of Resonators – an Ambiguous Term
2009-03-19: Scientific Progress: not as Straight a Process as it Seems
2009-03-07: Complicated Pulse Shapes from Q-switched Fiber Lasers
2009-03-02: User Interfaces for Simulation Software
2009-02-13: Laser Beam Deflections: The Angle–Diameter Product
2009-01-12: Chaotic Lasing Generates Random Numbers
2009-01-05: Extremely Long Mode-locked Fiber Laser
2008-12-16: Why Fiber Amplifiers, not Fiber Lasers?
2008-11-25: The Gouy Phase Shift Speeds up Light
2008-11-08: Validating Numerical Simulation Software
2008-10-20: Rate Equations – An Example of Stiff Sets of Differential Equations
2008-10-03: Wavelength-Tunable Lasers: Does the Tuner Degrade the Power Efficiency?
2008-09-24: Decoupling Pulse Duration and Pulse Energy
2008-09-10: Unpolarized Single-Frequency Output
2008-08-28: Photographs for the Encyclopedia of Laser Physics and Technology
2008-08-15: Print Version of the Encyclopedia of Laser Physics and Technology
2008-07-26: Beat Signals with Zero Linewidth
2008-07-13: The Simplified History of the Michelson–Morley Experiment
2008-07-02: Stronger Focusing Avoids SESAM Damage
2008-06-20: All-in-One Ultrafast Laser Systems
2008-06-13: Heisenberg's Uncertainty Principle and the Transform Limit
2008-06-06: Fiber Lasers Which Are No Fiber Lasers
2008-05-25: Einstein and the Laser
2008-05-13: Easier Self-Starting Passive Mode Locking for Short Lasers
2008-05-05: Length of a Photon
2008-04-28: Different Kinds of Polarization
2008-04-22: Abused Photonics Terms: Coherence
2008-04-15: Abused Photonics Terms: Modes
2008-04-02: Solitons: Lower Dispersion, Stronger Dispersive Effects!
2008-03-26: Mode-Locked Lasers: Lower Average Powers in Shorter Pulses
2008-03-17: Ultrafast Fiber Lasers: Re-Inventing Mode Locking
2008-03-10: Automatic Phase Matching
2008-03-04: What is a High Laser Beam Quality?
2008-02-22: Launching Light from a Bulb into a Single-Mode Fiber
2008-02-14: How Laser Development Can Go Wrong
2008-02-12: Factor 2 in the Equation for Cross-Phase Modulation
2008-02-03: Quantifying the Chirp of Ultrashort Pulses
2008-01-27: Beam Quality in Second-Harmonic Generation
2008-01-14: Frequency Doubling: Long Pulses Cause Trouble
2008-01-06: Saturation Intensity or Saturation Fluence of a Saturable Absorber or a Laser Gain Medium: What Matters?
2007-12-18: The Role of Laser Safety Goggles
2007-12-11: The Idler Wave — Essential for Parametric Amplification and Oscillation
2007-12-03: New Paper on Power Scaling of Lasers
2007-11-26: Solving Laser Problems Step by Step
2007-11-19: Walk-Off and Phase-Matching Bandwidth in Nonlinear Crystals
2007-11-10: Retirement of Prof. David C. Hanna
2007-11-02: Ultrafast Laser Kills Viruses
2007-10-31: Thermal Equilibrium in Laser Crystals
2007-10-25: The Gain Bandwidth of Laser Crystals and Glasses
2007-10-17: Why the Second-Harmonic Beam is Smaller
2007-10-11: Understanding Fourier Spectra
2007-10-07: Effective Refractive Index: Correcting a Common Belief
2007-09-27: Light Plus Light = Darkness: No Energy Problem, but Quantum Weirdness
2007-09-21: Optimum Crystal Length for Frequency Doubling
2007-09-13: Using Figures of the Encyclopedia in Your Publications, and Citing the Encyclopedia
2007-09-07: Power Scaling in Downward Direction
2007-09-01: Stimulated Brillouin Scattering: Lower Peak Power, Stronger Effect?
2007-08-27: Distant Healing of Lasers
2007-08-23: An OPO Without Resonator Mirrors
2007-08-22: Saturation of Pump Absorption - An Important Issue?
2007-08-15: Light = Electromagnetic Waves?
2007-08-06: Fiber Amplifiers: More ASE for Larger Core with Higher NA?
2007-07-30: Fiber Amplifiers: Stronger ASE in Backward Direction
2007-07-25: Higher Heat Generation Density, Stronger Thermal Effects?
2007-07-16: Mode Competition - Increased or Decreased by Spatial Hole Burning?
2007-07-11: What is a Beam Width, Beam Size, and a Beam Waist?
2007-07-06: Promoting Dangerous Practices in Laser Labs
2007-07-01: Nonsensical Regulations Undermine Laser Safety
2007-06-24: The Plague of a Narrow Emission Linewidth
2007-06-11: Beam Quality Measurements Can Easily Go Wrong
2007-06-01: Characterize Your Pump Beam!
2007-05-26: Optical Isotropy: Nonlinear Interactions are Different!
2007-05-19: Why Strong Birefringence in Fibers Helps
2007-05-10: Fundamental Limitation for sigma–tau Product, Gain Efficiency, and Laser Threshold
2007-04-28: Easier Launching into Fibers with Large Mode Area?
2007-04-16: Questions and Answers on Shot Noise
2007-04-01: The Ideal Pump Intensity Distribution in an End-Pumped Solid-State Laser
2007-03-23: Explaining the Nature of Photons to Lay Persons
2007-03-11: Divided-Pulse Amplification
2007-03-09: The Trouble with Crystal and Coating Damage
2007-03-05: More Efficient Frequency Doubling with Shorter Pulses?
2007-02-26: No Laser, no Result?
2007-02-22: Lossy Laser Cavities
2007-02-16: The Science of Biophotons
2007-02-09: Papers Reporting Yet Another Laser Crystal
2007-02-04: Continuing Struggle for Larger Fiber Mode Areas
2007-01-27: Noise Figure of Amplifiers
2007-01-21: Laser Operation Far Above Threshold
2007-01-15: Origins of Heating in Laser Crystals
2007-01-09: The Myth of Fiber-Optic Polar Bears
2007-01-05: Why the Encyclopedia of Laser Physics and Technology is Successful
2006-12-31: Peak Position of an Optical Spectrum
2006-12-16: Dangerous Green Laser Pointers
2006-12-09: The Laser Industry — High Tech or Low Tech?
2006-12-03: Diffraction in Optical Fibers
2006-11-28: The Role of Diffraction in Optical Resonators
2006-11-21: The Resonator Mystery
2006-11-16: Laser Models — not Always Useful
2006-11-04: Nd:YVO4 Laser with Polarization-Independent Pump Absorption
2006-11-02: Reflection Spectrum of Tilted Dielectric Mirror
2006-10-26: Residual Transmission Through Highly Reflecting Mirrors
2006-10-22: Lasers Attract Dust to Cavity Mirrors
2006-10-17: A Cute New Imaging Technique Named Compressive Imaging
2006-10-16: Using a Transimpedance Amplifier for Optical Power Measurements and Recording with a Photodiode
2006-10-15: Fivehundred Articles in the Encyclopedia of Laser Physics and Technology
2006-10-09: Correct Specifications for Laser Noise — Valuable but Hard to Obtain
2006-10-04: Higher-Order Modes of Fibers: a Solution for Single-Mode Guidance with Large Mode Area?
2006-10-01: Stability Zones of Laser Resonators
2006-09-29: Frequency Dependence of the Conversion Efficiency for Frequency Doubling
2006-09-22: Coherence Length of Ultrashort Pulses
2006-09-21: Power Scaling Limits of Optical Parametric Amplifiers
2006-09-16: Q-switched Lasers: YAG versus Vanadate
2006-09-06: Quenching Degrades the Efficiency of Some Ytterbium-Doped Gain Media
2006-09-03: Resolution of Conundrum: Threshold Power for Parametric Nonlinear Interactions
2006-09-01: Test Yourself with the Photonics Quiz
2006-08-23: Lasers with Nonlinear Input–Output Characteristics
2006-08-20: Lower Noise from Longer Lasers
2006-08-18: Resolution of Conundrum: No Magnetic Field on the Axis of a Coil
2006-08-15: The Effect of a Double Pass in a Frequency Doubler
2006-08-12: Understanding Quasi-Three-Level Lasers
2006-08-10: Single-Mode Fibers with Large Mode Areas
2006-08-01: Lasers Disturbed by Vacuum?
2006-07-30: Threshold Power for Parametric Nonlinear Interactions
2006-07-24: Beam Distortions in Laser Cavities
2006-07-23: Single-Atom Lasers
2006-07-22: No Magnetic Field on the Axis of a Coil?
2006-07-21: Photonics and Laser Technology Blogs – Where Are They?
2006-07-16: Spontaneous Emission and Amplifier Noise
2006-07-14: Lasers Like it Cool
2006-07-10: Strength of Thermal Lensing Effects
2006-07-05: Laser Design: Side Product or the Basis of Laser Development?
2006-07-01: With Wavelength Combs to Picometer Resolution