Nanophotonics Research Papers - Academia.edu (original) (raw)
Two twelve-channel arrays based on surface-etched slot gratings, one with nonuniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater than 40 nm,... more
Two twelve-channel arrays based on surface-etched slot gratings, one with nonuniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater than 40 nm, with a side-mode suppression ratio (SMSR) > 40 dB over much of this range and output power greater than 20 mW, was obtained for the array with non-uniform slots over a temperature range of 15°C-60°C. The introduction of multiple slot periods, chosen such that there is minimal overlap among the side reflection peaks, is employed to suppress modes lasing one free spectral range (FSR) from the intended wavelength. The tuning range of the array with uniformly spaced slots, on the other hand, was found to be discontinuous due to mode-hopping to modes one FSR away from the intended lasing mode which are not adequately suppressed. Spectral linewidth was found to vary across devices with the lowest measured linewidths in the range of 2 MHz to 4 MHz.
- by Jorge Simon and +1
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- Antennas, Nanophotonics, Far Infrared Physics, Radiation Detectors
In this paper, mode generation based on an elliptical core few mode fiber (EC-FMF) is devised through an inverse function, designed using split step beam propagation method (BPM). The undesired modes from an EC-FMF are eliminated through... more
In this paper, mode generation based on an elliptical core few mode fiber (EC-FMF) is devised through an inverse function, designed using split step beam propagation method (BPM). The undesired modes from an
EC-FMF are eliminated through an appended waveguide computed from the inverse phase of undesired modes. The EC-FMF may be used as an all-optical switch.
The effect of induced transparency, which is related to photoinduced bleaching of photoabsorbers, is being intensely studied and has many applications in the field of sensing. Along with this classical effect, numerous studies on induced... more
The effect of induced transparency, which is related to photoinduced bleaching of photoabsorbers, is being intensely studied and has many applications in the field of sensing. Along with this classical effect, numerous studies on induced transparency in coupled plasmon-exciton systems, which is accompanied by the formation of hybrid states, have been recently published. The formation of a new coupled system results in various spectral modifications. For example, induced transparency manifests itself as a narrow dip in the absorption spectrum of a coupled system. This effect can be used in sensing, the feasibility of which is the main objective here, where a variety of materials and methods for obtaining the induced transparency are considered. Various morphologies and geometries of plasmonic nanoparticles are discussed as well as types of molecular absorbers to assess the most favorable combinations for the evolvement of induced transparency. The potential applications of the induced transparency effect in sensing and molecular diagnostics are summarized.
An overview of how viruses-retroviruses could be utilized as to instigate viral bio-weaponization and bio-warfare (much like other pathogens as bacteria, fungi, etc.), as well as a highlight of the history of how this has occurred in the... more
An overview of how viruses-retroviruses could be utilized as to instigate viral bio-weaponization and bio-warfare (much like other pathogens as bacteria, fungi, etc.), as well as a highlight of the history of how this has occurred in the past, has been presented. In particular, two issues need to be clarified here. First of all, almost all of our history of evolution prior to 5,500 years ago has been purged from the records, as well any memory of such happenings have been blank-slated from our consciousness memories. Secondly, that humanity has been lurking in the low dimensional level of consciousness, without having a clue about some of the advanced technologies with regard to the true nature of its genetics, and the possibility of its manipulation leading to genetic mutations and alien hybridization. However, as of more recently, with the advent of knowledge of radiation technological development, together with more novel approaches as nanotechnology in materials science, as well as the fact that we are beginning to better understand the nature of our bioenergetics and the role it plays in our genetics and physiognomy and holographic reality, we are beginning to get a better grasp of how a formidable nefarious alien artificial intelligence machinery can play a devastating role in our genetic modification, hybridization, as well as the using viral bio-weaponization for our demise or total annihilation. Thus, in the present paper, the author
Research in solid-state nanophotonics and quantum optics has been recently pushing the limits in semiconductor microcavity design. High quality microcavities that confine light into small volumes are now able to drastically alter the... more
Research in solid-state nanophotonics and quantum optics has been recently pushing the limits in semiconductor microcavity design. High quality microcavities that confine light into small volumes are now able to drastically alter the local density of states (LDOS). Plasmonic systems can provide smaller effective confinements, however it is unclear if the benefits of confinement are good enough to balance material losses due to non-radiative
processes. This thesis presents a compendium of techniques for calculating photonic Green functions in various lossy, inhomogeneous magneto-dielectric systems. Subsequently we derive a rigorous theory of quantum light-matter interactions, valid in both weak and strong coupling limits, and show how the classical photonic Green function is developed to calculate Purcell factors, Lamb shifts, and the near and far field spectra from a single photon emitter. Using these techniques, this work investigates the classical and quantum optical properties of a variety of inhomogeneous structures, including their coupling to single photon emitters. This includes examining Purcell factors above negative index slabs and showing the convergence of many slow-light modes leads to a drastic increase in the LDOS along with large Lamb shifts. The optical trapping of metallic nanoparticles is examined
above a negative index slab and a silver half-space, showing the importance of interparticle coupling on the optical forces. Then the interaction between a quantum dot and a metallic nanoparticle is studied where far-field strong coupling effects are observed only when the metallic nanoparticle is considered beyond the dipole approximation. Finally, this work addresses the issue of the LDOS diverging in lossy materials, which necessitates a description of spontaneous emission beyond the dipole approximation; the “local field problem” in quantum optics is revisited and generalized to include local field corrections for use in any photonic medium. The strength of finite-difference time-domain techniques is demonstrated in a number of cases for the calculation of regularized Green functions in lossy inhomogeneous media. This thesis presents a comprehensive study of Green function approaches to model classical and quantum light-matter interactions in arbitrary nanophotonic structures, including quantum dots, semiconductor microcavities, negative index waveguides, metallic half-spaces and metallic nanoparticles.
An overview of what constitutes or signifies a "virus" has been presented. It is explicated that viruses are NOT solar organic living organisms, as inconsistent with what epitomizes a living organic organism, they are: (1) void of a... more
An overview of what constitutes or signifies a "virus" has been presented. It is explicated that viruses are NOT solar organic living organisms, as inconsistent with what epitomizes a living organic organism, they are: (1) void of a cellular structure, (2) they do not have a digestive nor respiratory system, (3) they do not procreate but are only capable of replication, and that only occurs when they invade the cellular body of an organic living organism and manage to use the genetic material of their invaded host to replicate themselves and multiply while causing genetic mutation of their invaded host, and (4) strictly speaking, they cannot self-evolve and can only mutate with the aid of the genetic material of the cellular structure of the organic organism pf their host. There have been several different theories proposed by biologists, virologists, and generally scientists, with regard to speculations of whether viruses can be construed as living organisms, but all are problematic with regard to their arguments presented. However, one thing is quite certain, that viruses can only exist in the environments that living organism thrive. In this respect, they can best be considered as parasitic 'replicators,' not suggesting that they necessarily feed upon their hosts, but need the genetic materials of their host in order to mutate their host cells to replicate. And, although nefarious viruses can cause infection in the organic body of their host eventuated by triggering the immune response of their host body causing illness and even death of their host, not all viruses are necessarily bad. In fact, viruses may be
We show explicitly how the commonly adopted prescription for calculating effective mode volumes is wrong and leads to uncontrolled errors. Instead, we introduce a generalized mode volume that can be easily evaluated based on the mode... more
We show explicitly how the commonly adopted prescription for calculating effective mode volumes is wrong and leads to uncontrolled errors. Instead, we introduce a generalized mode volume that can be easily evaluated based on the mode calculation methods typically applied in the literature, and which allows one to compute the Purcell effect and other interesting optical phenomena in a rigorous and unambiguous way.
- by Talha Erdem
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- Nanophotonics
The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip. The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of... more
The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip. The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits, giving rise to numerous metawaveguides with unprecedented strength in controlling guided electromagnetic waves. Here, we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms, such as dielectric or plasmonic waveguides and optical fibers. Foundational results and representative applications are comprehensively summarized. Brief physical models with explicit design tutorials, either physical intuition-based design methods or computer algorithms-based inverse designs, are cataloged as well. We highlight how meta-optics can infuse new degrees of freedom to waveguide-ba...
We study the strong coupling between photons and atoms that can be achieved in an optical nanofiber geometry when the interaction is dispersive. While the Purcell enhancement factor for spontaneous emission into the guided mode does not... more
We study the strong coupling between photons and atoms that can be achieved in an optical nanofiber geometry when the interaction is dispersive. While the Purcell enhancement factor for spontaneous emission into the guided mode does not reach the strong-coupling regime for individual atoms, one can obtain high cooperativity for ensembles of a few thousand atoms due to the tight confinement of the guided modes and constructive interference over the entire chain of trapped atoms. We calculate the dyadic Green's function, which determines the scattering of light by atoms in the presence of the fiber, and thus the phase shift and polarization rotation induced on the guided light by the trapped atoms. The Green's function is related to a full Heisenberg-Langevin treatment of the dispersive response of the quantized field to tensor polarizable atoms. We apply our formalism to quantum nondemolition (QND) measurement of the atoms via polarimetry. We study shot-noise-limited detection of atom number for atoms in a completely mixed spin state and the squeezing of projection noise for atoms in clock states. Compared with squeezing of atomic ensembles in free space, we capitalize on unique features that arise in the nanofiber geometry including anisotropy of both the intensity and polarization of the guided modes. We use a first principles stochastic master equation to model the squeezing as function of time in the presence of decoherence due to optical pumping. We find a peak metrological squeezing of ∼ 5 dB is achievable with current technology for ∼ 2500 atoms trapped 180 nm from the surface of a nanofiber with radius a = 225 nm.
Dynamic manipulation of wavefront is vital for massive free-space optical applications. Here we propose a set of largely tunable circular polarization splitters leveraging graphene nanoantennas with high efficiency reaching 83% and wide... more
Dynamic manipulation of wavefront is vital for massive free-space optical applications. Here we propose a set of largely tunable circular polarization splitters leveraging graphene nanoantennas with high efficiency reaching 83% and wide frequency tunability range of 2 to 5 THz. By synergizing the electrically tunable surface plasmons of graphene with phase gradient metasurface, we numerically demonstrate two kinds of polarization split-ters with complimentary graphene patterns to realize electrical tuning of operation frequency and efficient circular polarization demultiplexing. Using antennas of different geometric sizes, the device performances are investigated in several different terahertz bands. Our proposed structures can facilitate dynamically tunable broadband and high-speed applications such as polarization demultiplexing and optical switches in terahertz regime.
— Realizing small-footprint and energy-efficient optical switching fabrics is of crucial importance to solve the data movement challenges faced by optical interconnection networks. This letter demonstrates silicon photonic 2 × 2 full... more
— Realizing small-footprint and energy-efficient
optical switching fabrics is of crucial importance to solve the data
movement challenges faced by optical interconnection networks.
This letter demonstrates silicon photonic 2 × 2 full crossbar
switching functionality based on a single microring. The ultracompact
device is shown to successfully switch data channels
from two input ports simultaneously. Data channels in both the
multiple and the same wavelength switching experiments are
measured to be error-free. Simulation shows that by optimizing
some of the microring parameters crosstalk could be reduced.
This letter confirms the applicability of a single microring as
a 2 × 2 switch element for on-chip optical interconnects.
A new way of converting infrared light into visible wavelengths could make it possible to detect and measure mid-infrared signals using cheap and efficient sensors like those found in mobile phone cameras. [32] Looking ahead, the team... more
A new way of converting infrared light into visible wavelengths could make it possible to detect and measure mid-infrared signals using cheap and efficient sensors like those found in mobile phone cameras. [32] Looking ahead, the team says it now plans to further explore multimode mixing in gasfilled fibres. "Such studies will be an exciting playground for nonlinear optical interactions that can provide us with new tools to tailor optical waveforms at the fewcycle level," Razzari tells Physics World. [31] Laser ignition (LI) is a promising electrode-less alternative to electronic spark ignition of lean fuel/air mixtures, offering high thermal efficiency with low harmful emissions. [30] Scientists have developed a new type of laser that can deliver high amounts of energy in very short bursts of time, with potential applications in eye and heart surgery or the engineering of delicate materials. [29] So far, the researchers' calculations do not extend to the behavior of a zero-charge polyacetylene soliton that carries spin, but they expect that it should be possible to manipulate this with a magnetic field gradient.
Focusing and guiding light into semiconductor nano-structures can deliver revolutionary concepts for photonic devices, which offer a practical pathway towards next-generation power-efficient optical networks. In this review, we consider... more
Focusing and guiding light into semiconductor nano-structures can deliver revolutionary concepts for photonic devices, which offer a practical pathway towards next-generation power-efficient optical networks. In this review, we consider the prospects for photonic switches using semiconductor quantum dots (QDs) and photonic cavities which possess unique properties based on their low dimensionality. The optical nonlinearity of such photonic switches is theoretically analysed by introducing the concept of a field enhancement factor. This approach reveals a drastic improvement in both power-density and speed, which is able to overcome the limitations that have beset conventional photonic switches for decades. In addition, the overall power consumption is reduced due to the atom-like nature of QDs, as well as the nano-scale footprint of photonic cavities. Based on this theoretical perspective, the current state-of-the-art QD/cavity switches are reviewed in terms of various optical nonlinearity phenomena that have been utilized to demonstrate photonic switching. Emerging techniques, enabled by cavity nonlinear effects such as wavelength tuning, Purcell-factor tuning and plasmonic effects, are also discussed.
- by Manuel Nieto-Vesperinas and +1
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- Optics, Nanophotonics, Electromagnetics
The in situ synthesis and patterning of CdS nanocrystals in a polymer matrix is performed via multi-photon absorption. Quantum-sized CdS nanocrystals are obtained by irradiating a cadmium thiolate precursor dispersed in a transparent... more
The in situ synthesis and patterning of CdS nanocrystals in a polymer matrix is performed via multi-photon absorption. Quantum-sized CdS nanocrystals are obtained by irradiating a cadmium thiolate precursor dispersed in a transparent polymer matrix with a focused near infrared femtosecond laser beam. High resolution transmission electron microscopy evidences the formation of nanocrystals with wurtzite crystalline phase. Fluorescent, nanocomposite patterns with sub-micron spatial resolution are fabricated by scanning the laser beam on the polymer–precursor composite. Moreover, the emission energy of the CdS nanocrystals can be tuned in the range 2.5–2.7 eV, by changing the laser fluences in the range 0.10–0.45 J cm−2. This method enables therefore the synthesis of luminescent, CdS-based composites to be used within patterned nanophotonic and light-emitting devices.
Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific, technological, and industrial potential. In ultrafast laser manufacturing, optical energy of... more
Processing of materials by ultrashort laser pulses has evolved significantly over the last
decade and is starting to reveal its scientific, technological, and industrial potential. In
ultrafast laser manufacturing, optical energy of tightly focused femtosecond or
picosecond laser pulses can be delivered to precisely defined positions in the bulk of
materials via two-/multi-photon excitation on a timescale much faster than thermal
energy exchange between photoexcited electrons and lattice ions. Control of photoionization
and thermal processes with the highest precision, inducing local
photomodification in sub- 100-nm sized regions has been achieved.
State-of-the-art ultrashort laser processing techniques exploit high 0.1–1 μm spatial
resolution and almost unrestricted three-dimensional structuring capability. Adjustable
pulse duration, spatiotemporal chirp, phase front tilt, and polarization allow control of
photomodification via uniquely wide parameter space. Mature opto-electrical/mechanical
technologies have enabled laser processing speeds approaching meters-per-second,
leading to a fast lab-to-fab transfer. The key aspects and latest achievements are reviewed
with an emphasis on the fundamental relation between spatial resolution and total
fabrication throughput. Emerging biomedical applications implementing micrometer
feature precision over centimeter-scale scaffolds and photonic wire bonding in
telecommunications are highlighted.
Metasurface is a recently developed nanophotonics concept to manipulate the properties of light by replacing conventional bulky optical components with ultrathin (more than 104 times thinner) flat optical components. Since the first... more
Metasurface is a recently developed nanophotonics concept to manipulate the properties of light by replacing conventional bulky optical components with ultrathin (more than 104 times thinner) flat optical components. Since the first demonstration of metasurfaces in 2011, they have attracted tremendous interest in the consumer optics and electronics industries. Recently, metasurface-empowered novel bioimaging and biosensing tools have emerged and been reported. Given the recent advances in metasurfaces in biomedical engineering, this review article covers the state of the art for this technology and provides a comprehensive interdisciplinary perspective on this field. The topics that we have covered include metasurfaces for chiral imaging, endoscopic optical coherence tomography, fluorescent imaging, super-resolution imaging, magnetic resonance imaging, quantitative phase imaging, sensing of antibodies, proteins, DNAs, cells, and cancer biomarkers. Future directions are discussed in ...
- by Ali Kabiri
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- Nanophotonics
ABSTRACT Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride... more
ABSTRACT Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm exhibit plasmon resonance in the biological transparency window. With dimensions optimized for efficient cellular uptake, the nanoparticles demonstrate a high photothermal conversion efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization.
- by URCAN GULER
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- Nanophotonics
Scope & Topics Nanoscience and Technology: An International Journal (NTIJ) is a peer-reviewed, open access journal, addresses the impacts and challenges of Nanoscience and Technology. The journal documents practical and theoretical... more
Scope & Topics Nanoscience and Technology: An International Journal (NTIJ) is a peer-reviewed, open access journal, addresses the impacts and challenges of Nanoscience and Technology. The journal documents practical and theoretical results which make a fundamental contribution for the development of Nanoscience and Technology. This journal aims to bring together researchers and practitioners in all Nano aspects, including (but not limited to): Topics Of Intrested: ■ Micro / Nano Fabrication and Metrology ■ Micro / Nano Heat Transfer and Energy Information Technology, ■ Micro / Nano Sensors , Actuators and Systems Nanobionics ■ Micro / Nanofluidics and Bio Chips ■
This work aims to design a CMOS compatible, low-electrical power consumption modulator assisted by plasmons. For compactness and reduction of the electrical power consumption, electro-absorption based on the Franz-Keldysh effect in... more
This work aims to design a CMOS compatible, low-electrical power consumption modulator assisted by plasmons. For compactness and reduction of the electrical power consumption, electro-absorption based on the Franz-Keldysh effect in Germanium was chosen for modulation. It consists in the change of the absorption coefficient of the material near the band edge under the application of a static electric field, hence producing a direct modulation of the light intensity. The use of plasmons allows enhancing the electro-optical effect due to the high field confinement. An integrated electro-optical simulation tool was developed to design and optimize the modulator. The designed plasmonic modulator has an extinction ratio of 3.3 dB with insertion losses of 13.2 dB and electrical power consumption as low as 20 fJ/bit, i.e. the lowest electrical power consumption reported for silicon photonic modulators. In- and out-coupling to a standard silicon waveguide was also engineered by the means of an optimized Si-Ge taper, reducing the coupling losses to only 1 dB per coupler. Besides, an experimental work was carried out to try to shift the Franz-Keldysh effect, which is maximum at 1650 nm, to lower wavelength close to 1.55 μm for telecommunication applications.
Resonances of symmetric and antisymmetric polarization states in tightly coupled nanoshell particles made of either a metallic core and a dielectric shell or, vice versa, a dielectric core and a metallic shell were analyzed at optical... more
Resonances of symmetric and antisymmetric polarization states in tightly coupled nanoshell particles made of either a metallic core and a dielectric shell or, vice versa, a dielectric core and a metallic shell were analyzed at optical frequencies. The investigation was performed by using the single dipole approximation (SDA) with all the dynamical retarded field terms included. Furthermore, analytic formulas for