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Open AccessEditorial

Editorial: Guided-Wave Optics

by Boris A. Malomed

Appl. Sci. 2017, 7(9), 962; https://doi.org/10.3390/app7090962 - 20 Sep 2017

Cited by 3 | Viewed by 3568

Abstract

Guided waves represent a vast class of phenomena in which the propagation of collective excitations in various media is steered in required directions by fixed (or, sometimes, reconfigurable) conduits [...]
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(This article belongs to the Special Issue Guided-Wave Optics)

Research

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1407 KiB

Open AccessArticle

Stochastic and Higher-Order Effects on Exploding Pulses

by Orazio Descalzi and Carlos Cartes

Appl. Sci. 2017, 7(9), 887; https://doi.org/10.3390/app7090887 - 30 Aug 2017

Cited by 7 | Viewed by 3433

Abstract

The influence of additive noise, multiplicative noise, and higher-order effects on exploding solitons in the framework of the prototype complex cubic-quintic Ginzburg-Landau equation is studied. Transitions from explosions to filling-in to the noisy spatially homogeneous finite amplitude solution, collapse (zero solution), and periodic [...] Read more.

The influence of additive noise, multiplicative noise, and higher-order effects on exploding solitons in the framework of the prototype complex cubic-quintic Ginzburg-Landau equation is studied. Transitions from explosions to filling-in to the noisy spatially homogeneous finite amplitude solution, collapse (zero solution), and periodic exploding dissipative solitons are reported. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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5294 KiB

Open AccessArticle

Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers

by Arjunan Govindarajan, Boris A. Malomed, Arumugam Mahalingam and Ambikapathy Uthayakumar

Appl. Sci. 2017, 7(7), 645; https://doi.org/10.3390/app7070645 - 22 Jun 2017

Cited by 20 | Viewed by 4193

Abstract

We investigate modulational instability (MI) in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we identify MI conditions from [...] Read more.

We investigate modulational instability (MI) in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we identify MI conditions from the linearization with respect to small perturbations. First, we compare the MI spectra of the asymmetric system and its symmetric counterpart in the case of the anomalous group-velocity dispersion (GVD). In particular, it is demonstrated that the increase of the inter-core linear-coupling coefficient leads to a reduction of the MI gain spectrum in the asymmetric coupler. The analysis is extended for the asymmetric system in the normal-GVD regime, where the coupling induces and controls the MI, as well as for the system with opposite GVD signs in the two cores. Following the analytical consideration of the MI, numerical simulations are carried out to explore nonlinear development of the MI, revealing the generation of periodic chains of localized peaks with growing amplitudes, which may transform into arrays of solitons. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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2276 KiB

Open AccessArticle

Demonstration of High-Speed Optical Transmission at 2 µm in Titanium Dioxide Waveguides

by Manon Lamy, Christophe Finot, Julien Fatome, Juan Arocas, Jean-Claude Weeber and Kamal Hammani

Appl. Sci. 2017, 7(6), 631; https://doi.org/10.3390/app7060631 - 17 Jun 2017

Cited by 23 | Viewed by 5182

Abstract

We demonstrate the transmission of a 10-Gbit/s optical data signal in the 2 µm waveband into titanium dioxide waveguides. Error-free transmissions have been experimentally achieved taking advantage of a 23-dB insertion loss fiber-to-fiber grating-based injection test-bed platform. Full article

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2952 KiB

Open AccessArticle

Photon Propagation through Linearly Active Dimers

by José Delfino Huerta Morales and Blas Manuel Rodríguez-Lara

Appl. Sci. 2017, 7(6), 587; https://doi.org/10.3390/app7060587 - 7 Jun 2017

Cited by 7 | Viewed by 4121

Abstract

We provide an analytic propagator for non-Hermitian dimers showing linear gain or losses in the quantum regime. In particular, we focus on experimentally feasible realizations of the

PT

-symmetric dimer and provide their mean photon number and second order two-point correlation. We study [...] Read more.

We provide an analytic propagator for non-Hermitian dimers showing linear gain or losses in the quantum regime. In particular, we focus on experimentally feasible realizations of the

PT

-symmetric dimer and provide their mean photon number and second order two-point correlation. We study the propagation of vacuum, single photon spatially-separable, and two-photon spatially-entangled states. We show that each configuration produces a particular signature that might signal their possible uses as photon switches, semi-classical intensity-tunable sources, or spatially entangled sources to mention a few possible applications. Full article

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5757 KiB

Open AccessArticle

Waveguiding Light into Silicon Oxycarbide

by Faisal Ahmed Memon, Francesco Morichetti and Andrea Melloni

Appl. Sci. 2017, 7(6), 561; https://doi.org/10.3390/app7060561 - 30 May 2017

Cited by 13 | Viewed by 5682

Abstract

In this work, we demonstrate the fabrication of single mode optical waveguides in silicon oxycarbide (SiOC) with a high refractive index n = 1.578 on silica (SiO₂), exhibiting an index contrast of Δn = 8.2%. Silicon oxycarbide layers were deposited by [...] Read more.

In this work, we demonstrate the fabrication of single mode optical waveguides in silicon oxycarbide (SiOC) with a high refractive index n = 1.578 on silica (SiO₂), exhibiting an index contrast of Δn = 8.2%. Silicon oxycarbide layers were deposited by reactive RF magnetron sputtering of a SiC target in a controlled process of argon and oxygen gases. The optical properties of SiOC film were measured with spectroscopic ellipsometry in the near-infrared range and the acquired refractive indices of the film exhibit anisotropy on the order of 10⁻². The structure of the SiOC films is investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM). The channel waveguides in SiOC are buried in SiO₂ (n = 1.444) and defined with UV photolithography and reactive ion etching techniques. Propagation losses of about 4 dB/cm for both TE and TM polarizations at telecommunication wavelength 1550 nm are estimated with cut-back technique. Results indicate the potential of silicon oxycarbide for guided wave applications. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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2809 KiB

Open AccessArticle

Rogue Wave Modes for the Coupled Nonlinear Schrödinger System with Three Components: A Computational Study

by Hiu Ning Chan and Kwok Wing Chow

Appl. Sci. 2017, 7(6), 559; https://doi.org/10.3390/app7060559 - 29 May 2017

Cited by 10 | Viewed by 4627

Abstract

The system of “integrable” coupled nonlinear Schrödinger equations (Manakov system) with three components in the defocusing regime is considered. Rogue wave solutions exist for a restricted range of group velocity mismatch, and the existence condition correlates precisely with the onset of baseband modulation [...] Read more.

The system of “integrable” coupled nonlinear Schrödinger equations (Manakov system) with three components in the defocusing regime is considered. Rogue wave solutions exist for a restricted range of group velocity mismatch, and the existence condition correlates precisely with the onset of baseband modulation instability. This assertion is further elucidated numerically by evidence based on the generation of rogue waves by a single mode disturbance with a small frequency. This same computational approach can be adopted to study coupled nonlinear Schrödinger equations for the “non‐integrable” regime, where the coefficients of self‐phase modulation and cross‐phase modulation are different from each other. Starting with a wavy disturbance of a finite frequency corresponding to the large modulation instability growth rate, a breather can be generated. The breather can be symmetric or asymmetric depending on the magnitude of the growth rate. Under the presence of a third mode, rogue wave can exist under a larger group velocity mismatch between the components as compared to the two‐component system. Furthermore, the nonlinear coupling can enhance the maximum amplitude of the rogue wave modes and bright four‐petal configuration can be observed. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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1088 KiB

Open AccessArticle

Near-Field Coupling and Mode Competition in Multiple Anapole Systems

by Valerio Mazzone, Juan Sebastian Totero Gongora and Andrea Fratalocchi

Appl. Sci. 2017, 7(6), 542; https://doi.org/10.3390/app7060542 - 24 May 2017

Cited by 25 | Viewed by 7193

Abstract

All-dielectric metamaterials are a promising platform for the development of integrated photonics applications. In this work, we investigate the mutual coupling and interaction of an ensemble of anapole states in silicon nanoparticles. Anapoles are intriguing non-radiating states originated by the superposition of internal [...] Read more.

All-dielectric metamaterials are a promising platform for the development of integrated photonics applications. In this work, we investigate the mutual coupling and interaction of an ensemble of anapole states in silicon nanoparticles. Anapoles are intriguing non-radiating states originated by the superposition of internal multipole components which cancel each other in the far-field. While the properties of anapole states in single nanoparticles have been extensively studied, the mutual interaction and coupling of several anapole states have not been characterized. By combining first-principles simulations and analytical results, we demonstrate the transferring of anapole states across an ensemble of nanoparticles, opening to the development of advanced integrated devices and robust waveguides relying on non-radiating modes. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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1636 KiB

Open AccessArticle

Perfect Light Absorbers Made of Tungsten-Ceramic Membranes

by Masanobu Iwanaga

Appl. Sci. 2017, 7(5), 458; https://doi.org/10.3390/app7050458 - 29 Apr 2017

Cited by 10 | Viewed by 4230

Abstract

Plasmonic materials are expanding their concept; in addition to noble metals that are good conductors even at optical frequencies and support surface plasmon polaritons at the interface, other metals and refractory materials are now being used as plasmonic materials. In terms of complex [...] Read more.

Plasmonic materials are expanding their concept; in addition to noble metals that are good conductors even at optical frequencies and support surface plasmon polaritons at the interface, other metals and refractory materials are now being used as plasmonic materials. In terms of complex permittivity at optical frequencies, these new plasmonic materials are, though not ideal, quite good to support surface plasmons. Numerical investigations of the optical properties have been revealing new capabilities of the plasmonic materials. On the basis of the precise computations for electromagnetic waves in artificially designed nanostructures, in this article, we address membrane structures made of tungsten and silicon nitride that are a typical metal and ceramic, respectively, with high-temperature melting points. The membranes are applicable to low-power-consuming thermal emitters operating at and near the visible range. We numerically substantiate that the membranes serve as perfect light absorbers, in spite of the subwavelength thickness, that is, 200–250 nm thickness. Furthermore, we clarify that the underlying physical mechanism for the unconventional perfect absorption is ascribed to robust impedance matching at the interface between air and the membranes. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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4057 KiB

Open AccessFeature PaperArticle

Polarization Properties of Laser Solitons

by Pedro Rodriguez, Jesus Jimenez, Thierry Guillet and Thorsten Ackemann

Appl. Sci. 2017, 7(5), 442; https://doi.org/10.3390/app7050442 - 27 Apr 2017

Cited by 3 | Viewed by 5175

Abstract

The objective of this paper is to summarize the results obtained for the state of polarization in the emission of a vertical-cavity surface-emitting laser with frequency-selective feedback added. We start our research with the single soliton; this situation presents two perpendicular main orientations, [...] Read more.

The objective of this paper is to summarize the results obtained for the state of polarization in the emission of a vertical-cavity surface-emitting laser with frequency-selective feedback added. We start our research with the single soliton; this situation presents two perpendicular main orientations, connected by a hysteresis loop. In addition, we also find the formation of a ring-shaped intensity distribution, the vortex state, that shows two homogeneous states of polarization with very close values to those found in the soliton. For both cases above, the study shows the spatially resolved value of the orientation angle. It is important to also remark the appearance of a non-negligible amount of circular light that gives vectorial character to all the different emissions investigated. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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1780 KiB

Open AccessArticle

Stability and Dynamics of Dark-Bright Soliton Bound States Away from the Integrable Limit

by Garyfallia C. Katsimiga, Jan Stockhofe, Panagiotis G. Kevrekidis and Peter Schmelcher

Appl. Sci. 2017, 7(4), 388; https://doi.org/10.3390/app7040388 - 13 Apr 2017

Cited by 7 | Viewed by 3956

Abstract

The existence, stability, and dynamics of bound pairs of symbiotic matter waves in the form of dark-bright soliton pairs in two-component mixtures of atomic Bose–Einstein condensates is investigated. Motivated by the tunability of the atomic interactions in recent experiments, we explore in detail [...] Read more.

The existence, stability, and dynamics of bound pairs of symbiotic matter waves in the form of dark-bright soliton pairs in two-component mixtures of atomic Bose–Einstein condensates is investigated. Motivated by the tunability of the atomic interactions in recent experiments, we explore in detail the impact that changes in the interaction strengths have on these bound pairs by considering significant deviations from the integrable limit. It is found that dark-bright soliton pairs exist as stable configurations in a wide parametric window spanning both the miscible and the immiscible regime of interactions. Outside this parameter interval, two unstable regions are identified and are associated with a supercritical and a subcritical pitchfork bifurcation, respectively. Dynamical manifestation of these instabilities gives rise to a redistribution of the bright density between the dark solitons, and also to symmetry-broken stationary states that are mass imbalanced (asymmetric) with respect to their bright soliton counterpart. The long-time dynamics of both the stable and the unstable balanced and imbalanced dark-bright soliton pairs is analyzed. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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5912 KiB

Open AccessArticle

Pulse Propagation Models with Bands of Forbidden Frequencies or Forbidden Wavenumbers: A Consequence of Abandoning the Slowly Varying Envelope Approximation and Taking into Account Higher-Order Dispersion

by Jorge Fujioka, Alfredo Gómez-Rodríguez and Áurea Espinosa-Cerón

Appl. Sci. 2017, 7(4), 340; https://doi.org/10.3390/app7040340 - 30 Mar 2017

Cited by 1 | Viewed by 3571

Abstract

We study linear and nonlinear pulse propagation models whose linear dispersion relations present bands of forbidden frequencies or forbidden wavenumbers. These bands are due to the interplay between higher-order dispersion and one of the terms (a second-order derivative with respect to the propagation [...] Read more.

We study linear and nonlinear pulse propagation models whose linear dispersion relations present bands of forbidden frequencies or forbidden wavenumbers. These bands are due to the interplay between higher-order dispersion and one of the terms (a second-order derivative with respect to the propagation direction) which appears when we abandon the slowly varying envelope approximation. We show that as a consequence of these forbidden bands, narrow pulses radiate in a novel and peculiar way. We also show that the nonlinear equations studied in this paper have exact soliton-like solutions of different forms, some of them being embedded solitons. The solutions obtained (of the linear as well as the nonlinear equations) are interesting since several arguments suggest that the Cauchy problems for these equations are ill-posed, and therefore the specification of the initial conditions is a delicate issue. It is also shown that some of these equations are related to elliptic curves, thus suggesting that these equations might be related to other fields where these curves appear, such as the theory of modular forms and Weierstrass ℘ functions, or the design of cryptographic protocols. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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1456 KiB

Open AccessArticle

Dark Solitons and Grey Solitons in Waveguide Arrays with Long-Range Linear Coupling Effects

by Zhijie Mai, Haitao Xu, Fang Lin, Yan Liu, Shenhe Fu and Yongyao Li

Appl. Sci. 2017, 7(3), 311; https://doi.org/10.3390/app7030311 - 22 Mar 2017

Cited by 2 | Viewed by 3992

Abstract

In J. Phys. Soc. Jpn. 83, 034404 (2014), we designed a scheme of waveguide arrays with long-range linear coupling effects and studied the bright solitons in this system. In this paper, we further study the dynamics of dark and grey solitons in [...] Read more.

In J. Phys. Soc. Jpn. 83, 034404 (2014), we designed a scheme of waveguide arrays with long-range linear coupling effects and studied the bright solitons in this system. In this paper, we further study the dynamics of dark and grey solitons in such waveguide arrays. The numerical simulations show that the stabilities of dark solitons and grey solitons depend on the normalized decay length and the scaled input power. The width of dark solitons and the grey level of grey solitons are studied. Our results may contribute to the understanding of discrete solitons in long-range linear coupling waveguide arrays, and may have potential applications in optical communications and all-optical networks. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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642 KiB

Open AccessArticle

Existence, Stability and Dynamics of Nonlinear Modes in a 2D PartiallyPT Symmetric Potential

by Jennie D’Ambroise and Panayotis G. Kevrekidis

Appl. Sci. 2017, 7(3), 223; https://doi.org/10.3390/app7030223 - 27 Feb 2017

Cited by 1 | Viewed by 3847

Abstract

It is known that multidimensional complex potentials obeying parity-time(PT)symmetry may possess all real spectra and continuous families of solitons. Recently, it was shown that for multi-dimensional systems, these features can persist when the parity symmetry condition is relaxed so that the potential is [...] Read more.

It is known that multidimensional complex potentials obeying parity-time(PT)symmetry may possess all real spectra and continuous families of solitons. Recently, it was shown that for multi-dimensional systems, these features can persist when the parity symmetry condition is relaxed so that the potential is invariant under reﬂection in only a single spatial direction. We examine the existence, stability and dynamical properties of localized modes within the cubic nonlinear Schrödinger equation in such a scenario of partiallyPT-symmetric potential. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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2273 KiB

Open AccessArticle

A Metal-Insulator-Metal Deep Subwavelength Cavity Based on Cutoff Frequency Modulation

by Kihwan Moon, Tae-Woo Lee, Young Jin Lee and Soon-Hong Kwon

Appl. Sci. 2017, 7(1), 86; https://doi.org/10.3390/app7010086 - 17 Jan 2017

Cited by 8 | Viewed by 5752

Abstract

We propose a plasmonic cavity using the cutoff frequency of a metal-insulator-metal (MIM) first-order waveguide mode, which has a deep subwavelength physical size of 240 × 210 × 10 (nm³) = 0.00013 λ₀³. The cutoff frequency is a [...] Read more.

We propose a plasmonic cavity using the cutoff frequency of a metal-insulator-metal (MIM) first-order waveguide mode, which has a deep subwavelength physical size of 240 × 210 × 10 (nm³) = 0.00013 λ₀³. The cutoff frequency is a unique property of the first-order waveguide mode and provides an effective mode gap mirror. The cutoff frequency has strong dependence on a variety of parameters including the waveguide width, insulator thickness, and insulator index. We suggest new plasmon cavities using three types of cutoff frequency modulations. The light can be confined in the cavity photonically, which is based on the spatial change of the cutoff frequency. Furthermore, we analyze cavity loss by investigating the metallic absorption, radiation, and waveguide coupling loss; the radiation loss of the higher-order cavity mode can be suppressed by multipole cancellation. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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11460 KiB

Open AccessArticle

Designing a Novel High-Performance FBG-OADM Based on Finite Element and Eigenmode Expansion Methods

by Sheng-Chih Yang, Yue-Jing He and Yi-Jyun Wun

Appl. Sci. 2017, 7(1), 44; https://doi.org/10.3390/app7010044 - 30 Dec 2016

Cited by 1 | Viewed by 4256

Abstract

This study designed a novel high-performance fiber Bragg grating (FBG) optical add/drop multiplexers (OADMs) by referring to current numerical simulation methods. The proposed FBG-OADM comprises two single-mode fibers placed side by side. Both optical fibers contained an FBG featuring identical parameters and the [...] Read more.

This study designed a novel high-performance fiber Bragg grating (FBG) optical add/drop multiplexers (OADMs) by referring to current numerical simulation methods. The proposed FBG-OADM comprises two single-mode fibers placed side by side. Both optical fibers contained an FBG featuring identical parameters and the same geometric structure. Furthermore, it fulfills the full width at half maximum (FWHM) requirement for dense wavelength-division multiplexers (DWDMs) according to the International Telecommunication Union (i.e., FWHM < 0.4 nm). Of all related numerical calculation methods, the combination of the finite element method (FEM) and eigenmode expansion method (EEM), as a focus in this study, is the only one suitable for researching and designing large-scale components. To enhance the accuracy and computational performance, this study used numerical methods—namely, the object meshing method, the boundary meshing method, the perfectly matched layer, and the perfectly reflecting boundary—to simulate the proposed FBG-OADM. The simulation results showed that the novel FBG-OADM exhibited a −3 dB bandwidth of 0.0375 nm. In addition, analysis of the spectrum revealed that the drop port achieved the power output of 0 dB at an operating wavelength of 1550 nm. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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Review

Jump to: Editorial, Research

2191 KiB

Open AccessFeature PaperReview

Lévy Statistics and the Glassy Behavior of Light in Random Fiber Lasers

by Cid B. de Araújo, Anderson S. L. Gomes and Ernesto P. Raposo

Appl. Sci. 2017, 7(7), 644; https://doi.org/10.3390/app7070644 - 22 Jun 2017

Cited by 36 | Viewed by 4872

Abstract

The interest in random fiber lasers (RFLs), first demonstrated one decade ago, is still growing and their basic characteristics have been studied by several authors. RFLs are open systems that present instabilities in the intensity fluctuations due to the energy exchange among their [...] Read more.

The interest in random fiber lasers (RFLs), first demonstrated one decade ago, is still growing and their basic characteristics have been studied by several authors. RFLs are open systems that present instabilities in the intensity fluctuations due to the energy exchange among their non-orthogonal quasi-modes. In this work, we present a review of the recent investigations on the output characteristics of a continuous-wave erbium-doped RFL, with an emphasis on the statistical behavior of the emitted intensity fluctuations. A progression from the Gaussian to Lévy and back to the Gaussian statistical regime was observed by increasing the excitation laser power from below to above the RFL threshold. By analyzing the RFL output intensity fluctuations, the probability density function of emission intensities was determined, and its correspondence with the experimental results was identified, enabling a clear demonstration of the analogy between the RFL phenomenon and the spin-glass phase transition in disordered magnetic systems. A replica-symmetry-breaking phase above the RFL threshold was characterized and the glassy behavior of the emitted light was established. We also discuss perspectives for future investigations on RFL systems. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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3704 KiB

Open AccessFeature PaperReview

Soliton Content of Fiber-Optic Light Pulses

by Fedor Mitschke, Christoph Mahnke and Alexander Hause

Appl. Sci. 2017, 7(6), 635; https://doi.org/10.3390/app7060635 - 19 Jun 2017

Cited by 23 | Viewed by 8536

Abstract

This is a review of fiber-optic soliton propagation and of methods to determine the soliton content in a pulse, group of pulses or a similar structure. Of central importance is the nonlinear Schrödinger equation, an integrable equation that possesses soliton solutions, among others. [...] Read more.

This is a review of fiber-optic soliton propagation and of methods to determine the soliton content in a pulse, group of pulses or a similar structure. Of central importance is the nonlinear Schrödinger equation, an integrable equation that possesses soliton solutions, among others. Several extensions and generalizations of this equation are customary to better approximate real-world systems, but this comes at the expense of losing integrability. Depending on the experimental situation under discussion, a variety of pulse shapes or pulse groups can arise. In each case, the structure will contain one or several solitons plus small amplitude radiation. Direct scattering transform, also known as nonlinear Fourier transform, serves to quantify the soliton content in a given pulse structure, but it relies on integrability. Soliton radiation beat analysis does not suffer from this restriction, but has other limitations. The relative advantages and disadvantages of the methods are compared. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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5367 KiB

Open AccessReview

Ultrafast Optical Signal Processing with Bragg Structures

by Yikun Liu, Shenhe Fu, Boris A. Malomed, Iam Choon Khoo and Jianying Zhou

Appl. Sci. 2017, 7(6), 556; https://doi.org/10.3390/app7060556 - 27 May 2017

Cited by 13 | Viewed by 4378

Abstract

The phase, amplitude, speed, and polarization, in addition to many other properties of light, can be modulated by photonic Bragg structures. In conjunction with nonlinearity and quantum effects, a variety of ensuing micro- or nano-photonic applications can be realized. This paper reviews various [...] Read more.

The phase, amplitude, speed, and polarization, in addition to many other properties of light, can be modulated by photonic Bragg structures. In conjunction with nonlinearity and quantum effects, a variety of ensuing micro- or nano-photonic applications can be realized. This paper reviews various optical phenomena in several exemplary 1D Bragg gratings. Important examples are resonantly absorbing photonic structures, chirped Bragg grating, and cholesteric liquid crystals; their unique operation capabilities and key issues are considered in detail. These Bragg structures are expected to be used in wide-spread applications involving light field modulations, especially in the rapidly advancing field of ultrafast optical signal processing. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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8369 KiB

Open AccessReview

Guided Self-Accelerating Airy Beams—A Mini-Review

by Yiqi Zhang, Hua Zhong, Milivoj R. Belić and Yanpeng Zhang

Appl. Sci. 2017, 7(4), 341; https://doi.org/10.3390/app7040341 - 30 Mar 2017

Cited by 32 | Viewed by 8115

Abstract

Owing to their nondiffracting, self-accelerating, and self-healing properties, Airy beams of different nature have become a subject of immense interest in the past decade. Their interesting properties have opened doors to many diverse applications. Consequently, the questions of how to properly design the [...] Read more.

Owing to their nondiffracting, self-accelerating, and self-healing properties, Airy beams of different nature have become a subject of immense interest in the past decade. Their interesting properties have opened doors to many diverse applications. Consequently, the questions of how to properly design the spatial manipulation of Airy beams or how to implement them in different setups have become important and timely in the development of various optical devices. Here, based on our previous work, we present a short review on the spatial control of Airy beams, including the interactions of Airy beams in nonlinear media, beam propagation in harmonic potential, and the dynamics of abruptly autofocusing Airy beams in the presence of a dynamic linear potential. We demonstrate that, under the guidance of nonlinearity and an external potential, the trajectory, acceleration, structure, and even the basic properties of Airy beams can be adjusted to suit specific needs. We describe other fascinating phenomena observed with Airy beams, such as self-Fourier transformation, periodic inversion of Airy beams, and the appearance of spatial solitons in the presence of nonlinearity. These results have promoted the development of Airy beams, and have been utilized in various applications, including particle manipulation, self-trapping, and electronic matter waves. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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7816 KiB

Open AccessReview

Light Trapping above the Light Cone in One-Dimensional Arrays of Dielectric Spheres

by Evgeny N. Bulgakov, Almas F. Sadreev and Dmitrii N. Maksimov

Appl. Sci. 2017, 7(2), 147; https://doi.org/10.3390/app7020147 - 8 Feb 2017

Cited by 7 | Viewed by 5216

Abstract

We demonstrate bound states in the radiation continuum (BSC) in a linear periodic array of dielectric spheres in air above the light cone. We classify the BSCs by orbital angular momentum m = 0,±1,±2 according to the rotational symmetry of the array, Bloch [...] Read more.

We demonstrate bound states in the radiation continuum (BSC) in a linear periodic array of dielectric spheres in air above the light cone. We classify the BSCs by orbital angular momentum m = 0,±1,±2 according to the rotational symmetry of the array, Bloch wave vector ꞵ directed along the array according to the translational symmetry, and polarization. The most simple symmetry protectedBSCshavem = 0,ꞵ = 0 and occur in a wide range of the radius of the spheres and dielectric constant. More sophisticated BSCs with m 6= 0,ꞵ = 0 exist only for a selected radius of spheres at ﬁxed dielectric constant. We also ﬁnd robust Bloch BSCs with ꞵ 6= 0,m = 0. All BSCs reside within the ﬁrst but below the other diffraction continua. We show that the BSCs can be easily detected by bright features in scattering of different plane waves by the array as dependent on type of the BSC. The symmetry protected TE/TMBSCs can be traced by collapsing Fano resonance in cross-sections of normally incident TE/TM plane waves. When plane wave with circular polarization with frequency tuned to the bound states with OAM illuminates the array the spin angular momentum of the incident wave transfers into the orbital angular momentum of the BSC.This ,inturn, gives rise to giant vortical power currents rotating around the array. Incident wave with linear polarization with frequency tuned to the Bloch bound state in the continuum induces giant laminar power currents. At last, the plane wave with linear polarization incident under tilt relative to the axis of array excites Poynting currents spiralling around the array. It is demonstrated numerically that quasi-bound leaky modes of the array can propagate both stationary waves and light pulses to a distance of 60 wavelengths at the frequencies close to the bound states in the radiation continuum. A semi-analytical estimate for decay rates of the guided waves is found to match the numerical data to a good accuracy. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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