Next Issue
Previous Issue

Table of Contents

Photonics, Volume 2, Issue 2 (June 2015), Pages 317-757

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-30
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle Harmonic Mode-Locked Fiber Laser based on Photonic Crystal Fiber Filled with Topological Insulator Solution
Photonics 2015, 2(2), 342-354; doi:10.3390/photonics2020342
Received: 28 February 2015 / Revised: 28 March 2015 / Accepted: 29 March 2015 / Published: 3 April 2015
Cited by 1 | PDF Full-text (1282 KB) | HTML Full-text | XML Full-text
Abstract
We reported that the photonic crystal fiber (PCF) filled with TI:Bi2Te3 nanosheets solution could act as an effective saturable absorber (SA). Employing this TI-PCF SA device; we constructed an ytterbium-doped all-fiber laser oscillator and achieved the evanescent wave mode-locking operation.
[...] Read more.
We reported that the photonic crystal fiber (PCF) filled with TI:Bi2Te3 nanosheets solution could act as an effective saturable absorber (SA). Employing this TI-PCF SA device; we constructed an ytterbium-doped all-fiber laser oscillator and achieved the evanescent wave mode-locking operation. Due to the large cavity dispersion; the fundamental mode-locking pulse had the large full width at half maximum (FWHM) of 2.33 ns with the repetition rate of ~1.11 MHz; and the radio frequency (RF) spectrum with signal-to-noise ratio (SNR) of 61 dB. In addition; the transition dynamics from a bunched state of pulses to harmonic mode-locking (HML) was also observed; which was up to 26th order. Full article
Open AccessArticle Quantum Dot Laser for a Light Source of an Athermal Silicon Optical Interposer
Photonics 2015, 2(2), 355-364; doi:10.3390/photonics2020355
Received: 27 February 2015 / Revised: 27 March 2015 / Accepted: 30 March 2015 / Published: 3 April 2015
Cited by 1 | PDF Full-text (734 KB) | HTML Full-text | XML Full-text
Abstract
This paper reports a hybrid integrated light source fabricated on a silicon platform using a 1.3 μm wavelength quantum dot array laser. Temperature insensitive characteristics up to 120 °C were achieved by the optimum quantum dot structure and laser structure. Light output power
[...] Read more.
This paper reports a hybrid integrated light source fabricated on a silicon platform using a 1.3 μm wavelength quantum dot array laser. Temperature insensitive characteristics up to 120 °C were achieved by the optimum quantum dot structure and laser structure. Light output power was obtained that was high enough to achieve an optical error-free link of a silicon optical interposer. Furthermore, we investigated a novel spot size convertor in a silicon waveguide suitable for a quantum dot laser for lower energy cost operation of the optical interposer. Full article
(This article belongs to the Special Issue Quantum Dot Based Lasers and Photonic Devices)
Open AccessArticle A Simple First-Principles Homogenization Theory for Chiral Metamaterials
Photonics 2015, 2(2), 365-374; doi:10.3390/photonics2020365
Received: 4 March 2015 / Revised: 2 April 2015 / Accepted: 2 April 2015 / Published: 9 April 2015
Cited by 2 | PDF Full-text (207 KB) | HTML Full-text | XML Full-text
Abstract
We discuss a simple first-principles homogenization theory for describing, in the long-wavelength limit, the effective bianisotropic response of a periodic metamaterial composite without intrinsic chiral and magnetic inclusions. In the case where the dielectric contrast is low, we obtain a full analytical description
[...] Read more.
We discuss a simple first-principles homogenization theory for describing, in the long-wavelength limit, the effective bianisotropic response of a periodic metamaterial composite without intrinsic chiral and magnetic inclusions. In the case where the dielectric contrast is low, we obtain a full analytical description which can be considered the extension of Landau-Lifshitz-Looyenga effective-medium formulation in the context of periodic metamaterials. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Mesh Optimization for Monte Carlo-Based Optical Tomography
Photonics 2015, 2(2), 375-391; doi:10.3390/photonics2020375
Received: 19 March 2015 / Revised: 3 April 2015 / Accepted: 4 April 2015 / Published: 9 April 2015
PDF Full-text (1241 KB) | HTML Full-text | XML Full-text
Abstract
Mesh-based Monte Carlo techniques for optical imaging allow for accurate modeling of light propagation in complex biological tissues. Recently, they have been developed within an efficient computational framework to be used as a forward model in optical tomography. However, commonly employed adaptive mesh
[...] Read more.
Mesh-based Monte Carlo techniques for optical imaging allow for accurate modeling of light propagation in complex biological tissues. Recently, they have been developed within an efficient computational framework to be used as a forward model in optical tomography. However, commonly employed adaptive mesh discretization techniques have not yet been implemented for Monte Carlo based tomography. Herein, we propose a methodology to optimize the mesh discretization and analytically rescale the associated Jacobian based on the characteristics of the forward model. We demonstrate that this method maintains the accuracy of the forward model even in the case of temporal data sets while allowing for significant coarsening or refinement of the mesh. Full article
Open AccessArticle Self Referencing Heterodyne Transient Grating Spectroscopy with Short Wavelength
Photonics 2015, 2(2), 392-401; doi:10.3390/photonics2020392
Received: 16 March 2015 / Revised: 8 April 2015 / Accepted: 8 April 2015 / Published: 15 April 2015
PDF Full-text (558 KB) | HTML Full-text | XML Full-text
Abstract
Heterodyning by a phase stable reference electric field is a well known technique to amplify weak nonlinear signals. For short wavelength, the generation of a reference field in front of the sample is challenging because of a lack of suitable beamsplitters. Here, we
[...] Read more.
Heterodyning by a phase stable reference electric field is a well known technique to amplify weak nonlinear signals. For short wavelength, the generation of a reference field in front of the sample is challenging because of a lack of suitable beamsplitters. Here, we use a permanent grating which matches the line spacing of the transient grating for the creation of a phase stable reference field. The relative phase among the two can be changed by a relative translation of the permanent and transient gratings in direction orthogonal to the grating lines. We demonstrate the technique for a transient grating on a VO2 thin film and observe constructive as well as destructive interference signals. Full article
(This article belongs to the Special Issue Extreme UV Lasers: Technologies and Applications)
Open AccessArticle Analytic Characterization of the Dynamic Regimes of Quantum-Dot Lasers
Photonics 2015, 2(2), 402-413; doi:10.3390/photonics2020402
Received: 17 March 2015 / Revised: 7 April 2015 / Accepted: 8 April 2015 / Published: 15 April 2015
Cited by 1 | PDF Full-text (287 KB) | HTML Full-text | XML Full-text
Abstract
We present analytic treatment of the three different dynamic regimes found in quantum-dot laser turn-on and modulation dynamics. A dynamic coupling, and thus density-dependent scattering lifetimes between dots and reservoir, are identified to be crucial for a realistic modeling. We derive a minimal
[...] Read more.
We present analytic treatment of the three different dynamic regimes found in quantum-dot laser turn-on and modulation dynamics. A dynamic coupling, and thus density-dependent scattering lifetimes between dots and reservoir, are identified to be crucial for a realistic modeling. We derive a minimal model for the quantum-dot laser dynamics that can be seeded with experimentally accessible parameters, and give explicit analytic equations that are able to predict relaxation-oscillation frequency and damping rate. Full article
(This article belongs to the Special Issue Quantum Dot Based Lasers and Photonic Devices)
Open AccessArticle Gain and Threshold Current in Type II In(As)Sb Mid-Infrared Quantum Dot Lasers
Photonics 2015, 2(2), 414-425; doi:10.3390/photonics2020414
Received: 27 February 2015 / Revised: 10 April 2015 / Accepted: 11 April 2015 / Published: 15 April 2015
Cited by 1 | PDF Full-text (615 KB) | HTML Full-text | XML Full-text
Abstract
In this work, we improved the performance of mid-infrared type II InSb/InAs quantum dot (QD) laser diodes by incorporating a lattice-matched p-InAsSbP cladding layer. The resulting devices exhibited emission around 3.1 µm and operated up to 120 K in pulsed mode, which is
[...] Read more.
In this work, we improved the performance of mid-infrared type II InSb/InAs quantum dot (QD) laser diodes by incorporating a lattice-matched p-InAsSbP cladding layer. The resulting devices exhibited emission around 3.1 µm and operated up to 120 K in pulsed mode, which is the highest working temperature for this type of QD laser. The modal gain was estimated to be 2.9 cm−1 per QD layer. A large blue shift (~150 nm) was observed in the spontaneous emission spectrum below threshold due to charging effects. Because of the QD size distribution, only a small fraction of QDs achieve threshold at the same injection level at 4 K. Carrier leakage from the waveguide into the cladding layers was found to be the main reason for the high threshold current at higher temperatures. Full article
(This article belongs to the Special Issue Quantum Dot Based Lasers and Photonic Devices)
Open AccessArticle Experimental Demonstration of Luneburg Waveguides
Photonics 2015, 2(2), 440-448; doi:10.3390/photonics2020440
Received: 11 April 2015 / Accepted: 15 April 2015 / Published: 20 April 2015
Cited by 2 | PDF Full-text (553 KB) | HTML Full-text | XML Full-text
Abstract
Transformation optics gives rise to numerous unusual optical devices, such as novel metamaterial lenses and invisibility cloaks. Very recently, Mattheakis et al. (Luneburg lens waveguide networks. J. Opt. 2012, 14, 114006) have suggested theoretical design of an optical waveguide, based on
[...] Read more.
Transformation optics gives rise to numerous unusual optical devices, such as novel metamaterial lenses and invisibility cloaks. Very recently, Mattheakis et al. (Luneburg lens waveguide networks. J. Opt. 2012, 14, 114006) have suggested theoretical design of an optical waveguide, based on a network of Luneburg lenses, which may be useful in sensing and nonlinear optics applications. Here, we report the first experimental realization of such Luneburg waveguides. We have studied wavelength and polarization dependent performance of the waveguides. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Dispersive Response of a Disordered Superconducting Quantum Metamaterial
Photonics 2015, 2(2), 449-458; doi:10.3390/photonics2020449
Received: 8 April 2015 / Revised: 22 April 2015 / Accepted: 23 April 2015 / Published: 27 April 2015
Cited by 5 | PDF Full-text (698 KB) | HTML Full-text | XML Full-text
Abstract
We consider a disordered quantum metamaterial formed by an array of superconducting flux qubits coupled to microwave photons in a cavity. We map the system on the Tavis-Cummings model accounting for the disorder in frequencies of the qubits. The complex transmittance is calculated
[...] Read more.
We consider a disordered quantum metamaterial formed by an array of superconducting flux qubits coupled to microwave photons in a cavity. We map the system on the Tavis-Cummings model accounting for the disorder in frequencies of the qubits. The complex transmittance is calculated with the parameters taken from state-of-the-art experiments. We demonstrate that photon phase shift measurements allow to distinguish individual resonances in the metamaterial with up to 100 qubits, in spite of the decoherence spectral width being remarkably larger than the effective coupling constant. Our simulations are in agreement with the results of the recently reported experiment. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle FDTD for Hydrodynamic Electron Fluid Maxwell Equations
Photonics 2015, 2(2), 459-467; doi:10.3390/photonics2020459
Received: 15 April 2015 / Accepted: 4 May 2015 / Published: 6 May 2015
PDF Full-text (267 KB) | HTML Full-text | XML Full-text
Abstract
In this work, we develop a numerical method for solving the three dimensional hydrodynamic electron fluid Maxwell equations that describe the electron gas dynamics driven by an external electromagnetic wave excitation. Our numerical approach is based on the Finite-Difference Time-Domain (FDTD) method for
[...] Read more.
In this work, we develop a numerical method for solving the three dimensional hydrodynamic electron fluid Maxwell equations that describe the electron gas dynamics driven by an external electromagnetic wave excitation. Our numerical approach is based on the Finite-Difference Time-Domain (FDTD) method for solving the Maxwell’s equations and an explicit central finite difference method for solving the hydrodynamic electron fluid equations containing both electron density and current equations. Numerical results show good agreement with the experiment of studying the second-harmonic generation (SHG) from metallic split-ring resonator (SRR). Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Toward Super-Resolution Imaging at Green Wavelengths Employing Stratified Metal-Insulator Metamaterials
Photonics 2015, 2(2), 468-482; doi:10.3390/photonics2020468
Received: 30 March 2015 / Revised: 1 May 2015 / Accepted: 2 May 2015 / Published: 7 May 2015
Cited by 1 | PDF Full-text (1462 KB) | HTML Full-text | XML Full-text
Abstract
Metamaterials (MMs) are subwavelength-structured materials that have been rapidly developed in this century and have various potentials to realize novel phenomena, such as negative refraction, cloaking and super-resolution. Theoretical proposals for super-resolution image transfer using metallic thin films were experimentally demonstrated at ultraviolet
[...] Read more.
Metamaterials (MMs) are subwavelength-structured materials that have been rapidly developed in this century and have various potentials to realize novel phenomena, such as negative refraction, cloaking and super-resolution. Theoretical proposals for super-resolution image transfer using metallic thin films were experimentally demonstrated at ultraviolet and violet wavelengths from 365 to 405 nm. However, the most preferred wavelengths of optical imaging are green wavelengths around 500 nm, because optical microscopy is most extensively exploited in the area of biotechnology. In order to make the super-resolution techniques using MMs more practical, we propose the design of a stratified metal-insulator MM that has super-resolution image transfer modes at green wavelengths, which we here call hyper modes. The design assumed only Ag and SiO2 as constituent materials and was found employing Bloch-state analysis, which is based on a rigorous transfer-matrix method for the metal-insulator MMs. It is numerically substantiated that the designed stratified metal-insulator metamaterial (SMIM) is capable of forming super-resolution images at the green wavelengths, and optical loss reduction is also studied. We discuss the results derived by the Bloch-state analysis and by effective medium models usually used for the metal-insulator MMs and show that the Bloch-state analysis is more suitable to reproduce the experimental data. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Modeling of On-Chip Optical Nonreciprocity with an Active Microcavity
Photonics 2015, 2(2), 498-508; doi:10.3390/photonics2020498
Received: 14 April 2015 / Accepted: 5 May 2015 / Published: 13 May 2015
Cited by 2 | PDF Full-text (384 KB) | HTML Full-text | XML Full-text
Abstract
On-chip nonreciprocal light transport holds a great impact on optical information processing and communications based upon integrated photonic devices. By harvesting gain-saturation nonlinearity, we recently demonstrated on-chip optical asymmetric transmission at telecommunication bands with superior nonreciprocal performances using only one active whispering-gallery-mode microtoroid
[...] Read more.
On-chip nonreciprocal light transport holds a great impact on optical information processing and communications based upon integrated photonic devices. By harvesting gain-saturation nonlinearity, we recently demonstrated on-chip optical asymmetric transmission at telecommunication bands with superior nonreciprocal performances using only one active whispering-gallery-mode microtoroid resonator, beyond the commonly adopted magneto-optical (Faraday) effect. Here, detailed theoretical analysis is presented with respect to the reported scheme. Despite the fact that our model is simply the standard coupled-mode theory, it agrees well with the experiment and describes the essential one-way light transport in this nonreciprocal device. Further discussions, including the connection with the second law of thermodynamics and Fano resonance, are also briefly made in the end. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Tailoring Effective Media by Mie Resonances of Radially-Anisotropic Cylinders
Photonics 2015, 2(2), 509-526; doi:10.3390/photonics2020509
Received: 18 April 2015 / Accepted: 9 May 2015 / Published: 14 May 2015
Cited by 4 | PDF Full-text (314 KB) | HTML Full-text | XML Full-text
Abstract
This paper studies constructing advanced effective materials using arrays of circular radially-anisotropic (RA) cylinders. Homogenization of such cylinders is considered in an electrodynamic case based on Mie scattering theory. The homogenization procedure consists of two steps. First, we present an effectively isotropic model
[...] Read more.
This paper studies constructing advanced effective materials using arrays of circular radially-anisotropic (RA) cylinders. Homogenization of such cylinders is considered in an electrodynamic case based on Mie scattering theory. The homogenization procedure consists of two steps. First, we present an effectively isotropic model for individual cylinders, and second, we discuss the modeling of a lattice of RA cylinders. Radial anisotropy brings us extra parameters, which makes it possible to adjust the desired effective response for a fixed frequency. The analysis still remains simple enough, enabling a derivation of analytical design equations. The considered applications include generating artificial magnetism using all-dielectric cylinders, which is currently a very sought-after phenomenon in optical frequencies. We also study how negative refraction is achieved using magnetodielectric RA cylinders. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Multi-Format Wavelength Conversion Using Quantum Dash Mode-Locked Laser Pumps
Photonics 2015, 2(2), 527-539; doi:10.3390/photonics2020527
Received: 21 March 2015 / Accepted: 30 April 2015 / Published: 14 May 2015
Cited by 1 | PDF Full-text (532 KB) | HTML Full-text | XML Full-text
Abstract
We investigate and compare the performance of wavelength conversion for two different non-return-to-zero (NRZ) modulation formats at 40 Gb/s: on off keying (OOK) and differential phase-shift keying (DPSK). To achieve wide wavelength coverage and integrability, we use a dual pump scheme exploiting four-wave
[...] Read more.
We investigate and compare the performance of wavelength conversion for two different non-return-to-zero (NRZ) modulation formats at 40 Gb/s: on off keying (OOK) and differential phase-shift keying (DPSK). To achieve wide wavelength coverage and integrability, we use a dual pump scheme exploiting four-wave mixing in semiconductor optical amplifiers. For phase stability, we use a quantum-dash mode-locked laser (QD-MLL) as a multi-wavelength source for the dual pumps, with tunability provided by the output filter. The significant sidelobes of the DPSK spectrum (relative to OOK) require the balancing of the pump proximity to the original signal (facilitating high conversion efficiency) with the signal degradation from the pump spectrum overlapping the converted DPSK signal. We achieve a conversion efficiency near –3.6 dB for OOK and –5.4 dB for DPSK across a 12 nm tuning range with low input powers (1 dBm). We measure bit error rate (BER) and obtain error free transmission (BER < 109) with a power penalty less than 2 dB for OOK and 3 dB for DPSK. Full article
(This article belongs to the Special Issue Nonlinear Fiber Optics)
Open AccessArticle Creating and Controlling Polarization Singularities in Plasmonic Fields
Photonics 2015, 2(2), 553-567; doi:10.3390/photonics2020553
Received: 29 April 2015 / Revised: 17 May 2015 / Accepted: 18 May 2015 / Published: 22 May 2015
Cited by 2 | PDF Full-text (7991 KB) | HTML Full-text | XML Full-text
Abstract
Nanoscale light fields near nanoplasmonic objects can be highly structured and can contain highly-subwavelength features. Here, we present the results of our search for the simplest plasmonic system that contains, and can be used to control, the smallest such optical feature: an optical
[...] Read more.
Nanoscale light fields near nanoplasmonic objects can be highly structured and can contain highly-subwavelength features. Here, we present the results of our search for the simplest plasmonic system that contains, and can be used to control, the smallest such optical feature: an optical singularity. Specifically, we study the field around subwavelength holes in a metal film and look for polarization singularities. These can be circular (C)-points, at which the polarization is circular, or linear (L)-lines, where the polarization is linear. We find that, depending on the polarization of the incident light, two or three holes are sufficient to create a wealth of these singularities. Moreover, we find for the two-hole system that C-points are created in multiples of eight. This can be explained using symmetry arguments and conservation laws. We are able to predict where these singularities are created, their index and the topology of the field surrounding them. These results demonstrate the promise of this plasmonic platform as a tool for studying and controlling fundamental properties of light fields and may be important to applications where control over these properties is required at the nanoscale. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Circuit Model of Plasmon-Enhanced Fluorescence
Photonics 2015, 2(2), 568-593; doi:10.3390/photonics2020568
Received: 14 April 2015 / Accepted: 13 May 2015 / Published: 22 May 2015
Cited by 2 | PDF Full-text (659 KB) | HTML Full-text | XML Full-text
Abstract
Hybridized decaying oscillations in a nanosystem of two coupled elements—a quantum emitter and a plasmonic nanoantenna—are considered as a classical effect. The circuit model of the nanosystem extends beyond the assumption of inductive or elastic coupling and implies the near-field dipole-dipole interaction. Its
[...] Read more.
Hybridized decaying oscillations in a nanosystem of two coupled elements—a quantum emitter and a plasmonic nanoantenna—are considered as a classical effect. The circuit model of the nanosystem extends beyond the assumption of inductive or elastic coupling and implies the near-field dipole-dipole interaction. Its results fit those of the previously developed classical model of Rabi splitting, however going much farther. Using this model, we show that the hybridized oscillations depending on the relationships between design parameters of the nanosystem correspond to several characteristic regimes of spontaneous emission. These regimes were previously revealed in the literature and explained involving semiclassical theory. Our original classical model is much simpler: it results in a closed-form solution for the emission spectra. It allows fast prediction of the regime for different distances and locations of the emitter with respect to the nanoantenna (of a given geometry) if the dipole moment of the emitter optical transition and its field coupling constant are known. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial
Photonics 2015, 2(2), 594-603; doi:10.3390/photonics2020594
Received: 21 April 2015 / Accepted: 18 May 2015 / Published: 27 May 2015
Cited by 1 | PDF Full-text (438 KB) | HTML Full-text | XML Full-text
Abstract
We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM), strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in
[...] Read more.
We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM), strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle A Model for the Force Exerted on a Primary Cilium by an Optical Trap and the Resulting Deformation
Photonics 2015, 2(2), 604-618; doi:10.3390/photonics2020604
Received: 21 May 2015 / Revised: 25 May 2015 / Accepted: 27 May 2015 / Published: 29 May 2015
PDF Full-text (801 KB) | HTML Full-text | XML Full-text
Abstract
Cilia are slender flexible structures extending from the cell body; genetically similar to flagella. Although their existence has been long known, the mechanical and functional properties of non-motile (“primary”) cilia are largely unknown. Optical traps are a non-contact method of applying a localized
[...] Read more.
Cilia are slender flexible structures extending from the cell body; genetically similar to flagella. Although their existence has been long known, the mechanical and functional properties of non-motile (“primary”) cilia are largely unknown. Optical traps are a non-contact method of applying a localized force to microscopic objects and an ideal tool for the study of ciliary mechanics. We present a method to measure the mechanical properties of a cilium using an analytic model of a flexible, anchored cylinder held within an optical trap. The force density is found using the discrete-dipole approximation. Utilizing Euler-Bernoulli beam theory, we then integrate this force density and numerically obtain the equilibrium deformation of the cilium in response to an optical trap. The presented results demonstrate that optical trapping can provide a great deal of information and insight about the properties and functions of the primary cilium. Full article
(This article belongs to the Special Issue Optical Trapping in Biology and Nanotechnology)
Figures

Open AccessArticle Imaging Functions of Quasi-Periodic Nanohole Array as an Ultra-Thin Planar Optical Lens
Photonics 2015, 2(2), 619-633; doi:10.3390/photonics2020619
Received: 19 May 2015 / Revised: 9 June 2015 / Accepted: 9 June 2015 / Published: 12 June 2015
PDF Full-text (1084 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, the lensing functions and imaging abilities of a quasi-periodic nanohole array in a metal screen have been theoretically investigated and demonstrated. Such an optical binary mask with nanoholes designed in an aperiodic arrangement can function as an ultra-thin planar optical
[...] Read more.
In this paper, the lensing functions and imaging abilities of a quasi-periodic nanohole array in a metal screen have been theoretically investigated and demonstrated. Such an optical binary mask with nanoholes designed in an aperiodic arrangement can function as an ultra-thin planar optical lens, imaging complex structures composed of multiple light sources at tens of wavelengths away from the lens surface. Via resolving two adjacent testing objects at different separations, the effective numerical aperture (N.A.) and the effective imaging area of the planar optical lens can be evaluated, mimicking the imaging function of a conventional lens with high N.A. Furthermore, by using the quasi-periodic nanohole array as an ultra-thin planar optical lens, important applications such as X-ray imaging and nano-optical circuits may be found in circumstances where conventional optical lenses cannot readily be applied. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Optical Fiber Tweezers Fabricated by Guided Wave Photo-Polymerization
Photonics 2015, 2(2), 634-645; doi:10.3390/photonics2020634
Received: 19 May 2015 / Revised: 5 June 2015 / Accepted: 8 June 2015 / Published: 12 June 2015
Cited by 2 | PDF Full-text (593 KB) | HTML Full-text | XML Full-text
Abstract
In this work the use of guided wave photo-polymerization for the fabrication of novel polymeric micro tips for optical trapping is demonstrated. It is shown that the selective excitation of linear polarized modes, during the fabrication process, has a direct impact on the
[...] Read more.
In this work the use of guided wave photo-polymerization for the fabrication of novel polymeric micro tips for optical trapping is demonstrated. It is shown that the selective excitation of linear polarized modes, during the fabrication process, has a direct impact on the shape of the resulting micro structures. Tips are fabricated with modes LP02 and LP21 and their shapes and output intensity distribution are compared. The application of the micro structures as optical tweezers is demonstrated with the manipulation of yeast cells. Full article
(This article belongs to the Special Issue Optical Trapping in Biology and Nanotechnology)
Figures

Open AccessArticle Long-Wavelength InAs/GaAs Quantum-Dot Light Emitting Sources Monolithically Grown on Si Substrate
Photonics 2015, 2(2), 646-658; doi:10.3390/photonics2020646
Received: 29 May 2015 / Revised: 14 June 2015 / Accepted: 15 June 2015 / Published: 18 June 2015
Cited by 2 | PDF Full-text (2102 KB) | HTML Full-text | XML Full-text
Abstract
Direct integration of III–V light emitting sources on Si substrates has attracted significant interest for addressing the growing limitations for Si-based electronics and allowing the realization of complex optoelectronics circuits. However, the high density of threading dislocations introduced by large lattice mismatch and
[...] Read more.
Direct integration of III–V light emitting sources on Si substrates has attracted significant interest for addressing the growing limitations for Si-based electronics and allowing the realization of complex optoelectronics circuits. However, the high density of threading dislocations introduced by large lattice mismatch and incompatible thermal expansion coefficient between III–V materials and Si substrates have fundamentally limited monolithic epitaxy of III–V devices on Si substrates. Here, by using the InAlAs/GaAs strained layer superlattices (SLSs) as dislocation filter layers (DFLs) to reduce the density of threading dislocations. We firstly demonstrate a Si-based 1.3 µm InAs/GaAs quantum dot (QD) laser that lases up to 111 °C, with a low threshold current density of 200 A/cm2 and high output power over 100 mW at room temperature. We then demonstrate the operation of InAs/GaAs QD superluminescent light emitting diodes (SLDs) monolithically grown on Si substrates. The fabricated two-section SLD exhibits a 3 dB linewidth of 114 nm, centered at ~1255 nm with a corresponding output power of 2.6 mW at room temperature. Our work complements hybrid integration using wafer bonding and represents a significant milestone for direct monolithic integration of III–V light emitters on Si substrates. Full article
(This article belongs to the Special Issue Quantum Dot Based Lasers and Photonic Devices)
Open AccessArticle Enhancement and Tunability of Near-Field Radiative Heat Transfer Mediated by Surface Plasmon Polaritons in Thin Plasmonic Films
Photonics 2015, 2(2), 659-683; doi:10.3390/photonics2020659
Received: 19 May 2015 / Revised: 12 June 2015 / Accepted: 12 June 2015 / Published: 18 June 2015
Cited by 7 | PDF Full-text (6427 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength of thermal radiation. Using a rigorous fluctuational electrodynamics approach, we
[...] Read more.
The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength of thermal radiation. Using a rigorous fluctuational electrodynamics approach, we predict that ultra-thin films of plasmonic materials can be used to dramatically enhance near-field heat transfer. The total spectrally integrated film-to-film heat transfer is over an order of magnitude larger than between the same materials in bulk form and also exceeds the levels achievable with polar dielectrics such as SiC. We attribute this enhancement to the significant spectral broadening of radiative heat transfer due to coupling between surface plasmon polaritons (SPPs) on both sides of each thin film. We show that the radiative heat flux spectrum can be further shaped by the choice of the substrate onto which the thin film is deposited. In particular, substrates supporting surface phonon polaritons (SPhP) strongly modify the heat flux spectrum owing to the interactions between SPPs on thin films and SPhPs of the substrate. The use of thin film phase change materials on polar dielectric substrates allows for dynamic switching of the heat flux spectrum between SPP-mediated and SPhP-mediated peaks. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Figures

Open AccessArticle Scattering Intensity and Directionality Probed Along Individual Zinc Oxide Nanorods with Precisely Controlled Light Polarization and Nanorod Orientation
Photonics 2015, 2(2), 684-701; doi:10.3390/photonics2020684
Received: 20 May 2015 / Revised: 12 June 2015 / Accepted: 13 June 2015 / Published: 18 June 2015
Cited by 4 | PDF Full-text (2613 KB) | HTML Full-text | XML Full-text
Abstract
We elucidated the light-matter interaction of individual ZnO NRs with a monochromatic beam of linearly polarized light that scatters elastically from the ZnO NRs by performing forward scattering and back-aperture imaging in a dark-field setting. We precisely controlled the electric field vector of
[...] Read more.
We elucidated the light-matter interaction of individual ZnO NRs with a monochromatic beam of linearly polarized light that scatters elastically from the ZnO NRs by performing forward scattering and back-aperture imaging in a dark-field setting. We precisely controlled the electric field vector of the incident light and the NR orientation within the plane of light interaction during both modes of measurement, and spatially resolved the scattering response from different interaction points along the NR long axis. We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs. We identified distinctive scattering profiles from individual ZnO NRs subject to incident light polarization with controlled NR orientation from the forward dark-field scattering and back-aperture imaging modes. The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices. Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity. Full article
Open AccessArticle Analytical Solution for the Stopping Power of the Cherenkov Radiation in a Uniaxial Nanowire Material
Photonics 2015, 2(2), 702-718; doi:10.3390/photonics2020702
Received: 13 May 2015 / Revised: 12 June 2015 / Accepted: 13 June 2015 / Published: 19 June 2015
Cited by 4 | PDF Full-text (560 KB) | HTML Full-text | XML Full-text
Abstract
We derive closed analytical formulae for the power emitted by moving charged particles in a uniaxial wire medium by means of an eigenfunction expansion. Our analytical expressions demonstrate that, in the absence of material dispersion, the stopping power of the uniaxial wire medium
[...] Read more.
We derive closed analytical formulae for the power emitted by moving charged particles in a uniaxial wire medium by means of an eigenfunction expansion. Our analytical expressions demonstrate that, in the absence of material dispersion, the stopping power of the uniaxial wire medium is proportional to the charge velocity, and that there is no velocity threshold for the Cherenkov emission. It is shown that the eigenfunction expansion formalism can be extended to the case of dispersive lossless media. Furthermore, in the presence of material dispersion, the optimal charge velocity that maximizes the emitted Cherenkov power may be less than the speed of light in a vacuum. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessArticle Fano Resonance Enhanced Nonreciprocal Absorption and Scattering of Light
Photonics 2015, 2(2), 745-757; doi:10.3390/photonics2020745
Received: 17 May 2015 / Revised: 18 June 2015 / Accepted: 18 June 2015 / Published: 22 June 2015
Cited by 3 | PDF Full-text (2808 KB) | HTML Full-text | XML Full-text
Abstract
We reveal that asymmetric plasmonic nanostructures can exhibit significantly different absorption and scattering properties for light that propagates in opposite directions, despite the conservation of total extinction. We analytically demonstrate that this is a consequence of nonorthogonality of eigenmodes of the system. This
[...] Read more.
We reveal that asymmetric plasmonic nanostructures can exhibit significantly different absorption and scattering properties for light that propagates in opposite directions, despite the conservation of total extinction. We analytically demonstrate that this is a consequence of nonorthogonality of eigenmodes of the system. This results in the necessity for modal interference with potential enhancement via Fano resonances. Based on our theory, we propose a stacked nanocross design whose optical response exhibits an abrupt change between absorption and scattering cross-sections for plane waves propagating in opposite directions. This work thereby proposes the use of Fano resonances to employ nanostructures for measuring and distinguishing optical signals coming from opposite directions. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Figures

Review

Jump to: Research

Open AccessReview On the Importance of Electron Beam Brightness in High Gain Free Electron Lasers
Photonics 2015, 2(2), 317-341; doi:10.3390/photonics2020317
Received: 4 March 2015 / Revised: 23 March 2015 / Accepted: 24 March 2015 / Published: 27 March 2015
Cited by 3 | PDF Full-text (1414 KB) | HTML Full-text | XML Full-text
Abstract
Linear accelerators delivering high brightness electron beams are essential for driving short wavelength, high gain free-electron lasers (FELs). The FEL radiation output efficiency is often parametrized through the power gain length that relates FEL performance to electron beam quality at the undulator. In
[...] Read more.
Linear accelerators delivering high brightness electron beams are essential for driving short wavelength, high gain free-electron lasers (FELs). The FEL radiation output efficiency is often parametrized through the power gain length that relates FEL performance to electron beam quality at the undulator. In this review article we illustrate some approaches to the preliminary design of FEL linac-drivers, and analyze the relationship between the output FEL wavelength, exponential gain length and electron beam brightness. We extend the discussion to include FEL three-dimensional effects and electron beam projected emittances. Although mostly concentrating on FELs based upon self-amplified spontaneous emission (SASE), our findings are in some cases highly relevant to externally seeded FELs. Full article
(This article belongs to the Special Issue Extreme UV Lasers: Technologies and Applications)
Open AccessReview Sensitivity Enhancement for Fiber Bragg Grating Sensors by Four Wave Mixing
Photonics 2015, 2(2), 426-439; doi:10.3390/photonics2020426
Received: 3 March 2015 / Revised: 13 April 2015 / Accepted: 14 April 2015 / Published: 16 April 2015
Cited by 2 | PDF Full-text (925 KB) | HTML Full-text | XML Full-text
Abstract
All-optical signal processing based on four wave mixing (FWM) in a highly nonlinear fiber (HNLF) to enhance the sensitivity of a fiber sensor is demonstrated and comprehensively reviewed in this paper. The principle is based on the frequency chirp magnification (FCM) by FWM.
[...] Read more.
All-optical signal processing based on four wave mixing (FWM) in a highly nonlinear fiber (HNLF) to enhance the sensitivity of a fiber sensor is demonstrated and comprehensively reviewed in this paper. The principle is based on the frequency chirp magnification (FCM) by FWM. Degenerated FWM, cascaded two-stage FWM and pump-pulsed FWM with optical parametric amplification (OPA) are experimentally utilized for magnifying the frequency chirp. By using the pump pulse modulation to increase the peak power, OPA can be induced with the use of a dispersion-optimized HNLF. Therefore, ultra-highly efficient FWM can be realized due to the high peak power and OPA. By using the fiber Bragg grating (FBG) laser as the FWM pump, the wavelength drift of the FBG can thus be magnified due to the FCM. We obtain a sensing performance of 13.3 pm/με strain sensitivity and 141.2 pm/°C temperature sensitivity for a conventional FBG, which has an intrinsic strain sensitivity of only ~1 pm/με and an intrinsic temperature sensitivity of only ~10 pm/°C, respectively. Full article
(This article belongs to the Special Issue Nonlinear Fiber Optics)
Figures

Open AccessReview Chirality in Optical Trapping and Optical Binding
Photonics 2015, 2(2), 483-497; doi:10.3390/photonics2020483
Received: 26 March 2015 / Revised: 5 May 2015 / Accepted: 6 May 2015 / Published: 11 May 2015
Cited by 3 | PDF Full-text (649 KB) | HTML Full-text | XML Full-text
Abstract
Optical trapping is a well-established technique that is increasingly used on biological substances and nanostructures. Chirality, the property of objects that differ from their mirror image, is also of significance in such fields, and a subject of much current interest. This review offers
[...] Read more.
Optical trapping is a well-established technique that is increasingly used on biological substances and nanostructures. Chirality, the property of objects that differ from their mirror image, is also of significance in such fields, and a subject of much current interest. This review offers insight into the intertwining of these topics with a focus on the latest theory. Optical trapping of nanoscale objects involves forward Rayleigh scattering of light involving transition dipole moments; usually these dipoles are assumed to be electric although, in chiral studies, magnetic dipoles must also be considered. It is shown that a system combining optical trapping and chirality could be used to separate enantiomers. Attention is also given to optical binding, which involves light induced interactions between trapped particles. Interesting effects also arise when binding is combined with chirality. Full article
(This article belongs to the Special Issue Optical Trapping in Biology and Nanotechnology)
Figures

Open AccessReview Optical Scattering Cancellation through Arrays of Plasmonic Nanoparticles: A Review
Photonics 2015, 2(2), 540-552; doi:10.3390/photonics2020540
Received: 14 April 2015 / Revised: 12 May 2015 / Accepted: 12 May 2015 / Published: 18 May 2015
Cited by 4 | PDF Full-text (879 KB) | HTML Full-text | XML Full-text
Abstract
In this contribution, we review and discuss our recent results on the design of optical scattering cancellation devices based on an array of plasmonic nanoparticles. Starting from two different analytical models available to describe its electromagnetic behavior, we show that a properly designed
[...] Read more.
In this contribution, we review and discuss our recent results on the design of optical scattering cancellation devices based on an array of plasmonic nanoparticles. Starting from two different analytical models available to describe its electromagnetic behavior, we show that a properly designed array of plasmonic nanoparticles behaves both as an epsilon-near-zero metamaterial and as a reactive metasurface and, therefore, can be successfully used to reduce the optical scattering of a subwavelength object. Three different typologies of nanoparticle arrays are analyzed: spherical, core-shell, and ellipsoidal nanoparticles. We prove, both theoretically and through full-wave simulations, that such nanostructures can be successfully used as a cloaking device at ultraviolet and optical frequencies. Full article
(This article belongs to the Special Issue New Frontiers in Plasmonics and Metamaterials)
Open AccessReview Unlocking Spectral Versatility from Broadly−Tunable Quantum−Dot Lasers
Photonics 2015, 2(2), 719-744; doi:10.3390/photonics2020719
Received: 21 May 2015 / Revised: 15 June 2015 / Accepted: 16 June 2015 / Published: 22 June 2015
PDF Full-text (992 KB) | HTML Full-text | XML Full-text
Abstract
Wavelength−tunable semiconductor quantum−dot lasers have achieved impressive performance in terms of high−power, broad tunability, low threshold current, as well as broadly tunable generation of ultrashort pulses. InAs/GaAs quantum−dot−based lasers in particular have demonstrated significant versatility and promise for a range of applications in
[...] Read more.
Wavelength−tunable semiconductor quantum−dot lasers have achieved impressive performance in terms of high−power, broad tunability, low threshold current, as well as broadly tunable generation of ultrashort pulses. InAs/GaAs quantum−dot−based lasers in particular have demonstrated significant versatility and promise for a range of applications in many areas such as biological imaging, optical fiber communications, spectroscopy, THz radiation generation and frequency doubling into the visible region. In this review, we cover the progress made towards the development of broadly−tunable quantum−dot edge−emitting lasers, particularly in the spectral region between 1.0–1.3 µm. This review discusses the strategies developed towards achieving lower threshold current, extending the tunability range and scaling the output power, covering achievements in both continuous wave and mode−locked InAs/GaAs quantum−dot lasers. We also highlight a number of applications which have benefitted from these advances, as well as emerging new directions for further development of broadly−tunable quantum−dot lasers. Full article
(This article belongs to the Special Issue Quantum Dot Based Lasers and Photonic Devices)
Figures

Journal Contact

MDPI AG
Photonics Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
E-Mail: 
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Photonics Edit a special issue Review for Photonics
loading...
Back to Top