http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Wed, 24 Apr 2013 16:21:40 +0000 http://www.hindawi.com/journals/ijo/2013/253692/ A theory of generation of low- and high-index Bessel surface plasmon polaritons and their superposition in a metal film of a finite thickness is developed. Correct analytical expressions are obtained for the field of two families of Bessel surface plasmon polariton modes formed inside and outside the metal layer. The intensity distribution near the boundary of the layer has been calculated and analyzed. A scheme for the experimental realization of a superposition of Bessel surface plasmon polaritons is suggested. Our study demonstrates that it is feasible to use the superposition of Bessel surface plasmon polaritons as a virtual tip for near-field optical microscopy with a nanoscale resolution. S. N. Kurilkina, V. N. Belyi, and N. S. Kazak Copyright © 2013 S. N. Kurilkina et al. All rights reserved. Thu, 11 Apr 2013 18:00:24 +0000 http://www.hindawi.com/journals/ijo/2013/367967/ Polarization mode dispersion (PMD) field measurements on deployed buried fibres showed that the PMD variation over the 1520 to 1570 nm wavelength was stochastic. The PMD variation over the 98-hour period for each wavelength was directional and limited; they are due to the presence of random mode coupling along the fibre length and limited influence from extrinsic perturbations over time, respectively. PMD variation in the wavelength domain showed that the mean first-order PMD (FO-PMD) value is independent of whether the FO-PMD statistics of a fibre link approaches the Maxwellian theoretical distribution; the key factor is sufficient random mode coupling. The accompanying second-order PMD (SO-PMD) statistics, with FO-PMD statistics approaching Maxwellian, followed the PDF given by Foschini et al. (1999). The FO- and SO-PMD statistics at a given wavelength gave nonstochastic PMD distributions with time. Winston T. Ireeta, Vitalis Musara, Lorinda Wu, and Andrew W. R. Leitch Copyright © 2013 Winston T. Ireeta et al. All rights reserved. Sun, 30 Dec 2012 08:30:08 +0000 http://www.hindawi.com/journals/ijo/2012/740487/ Zhaolin Lu, Xiaoyue Huang, Mark Mirotznik, Georgios Veronis, and Qiwen Zhan Copyright © 2012 Zhaolin Lu et al. All rights reserved. Mon, 10 Dec 2012 10:38:42 +0000 http://www.hindawi.com/journals/ijo/2012/807052/ Francesco Prudenzano, Frédéric Smektala, and Luciano Mescia Copyright © 2012 Francesco Prudenzano et al. All rights reserved. Thu, 22 Nov 2012 10:11:51 +0000 http://www.hindawi.com/journals/ijo/2012/902849/ This work presents a bottom-up abstraction procedure based on the design-flow FDTD + SystemC suitable for the modelling of optical Networks-on-Chip. In this procedure, a complex network is decomposed into elementary switching elements whose input-output behavior is described by means of scattering parameters models. The parameters of each elementary block are then determined through 2D-FDTD simulation, and the resulting analytical models are exported within functional blocks in SystemC environment. The inherent modularity and scalability of the -matrix formalism are preserved inside SystemC, thus allowing the incremental composition and successive characterization of complex topologies typically out of reach for full-vectorial electromagnetic simulators. The consistency of the outlined approach is verified, in the first instance, by performing a SystemC analysis of a four-input, four-output ports switch and making a comparison with the results of 2D-FDTD simulations of the same device. Finally, a further complex network encompassing 160 microrings is investigated, the losses over each routing path are calculated, and the minimum amount of power needed to guarantee an assigned BER is determined. This work is a basic step in the direction of an automatic technology-aware network-level simulation framework capable of assembling complex optical switching fabrics, while at the same time assessing the practical feasibility and effectiveness at the physical/technological level. Alberto Parini, Luca Ramini, Fabio Lanzoni, Gaetano Bellanca, and Davide Bertozzi Copyright © 2012 Alberto Parini et al. All rights reserved. Thu, 22 Nov 2012 09:27:45 +0000 http://www.hindawi.com/journals/ijo/2012/575818/ Rare-earth-doped chalcogenide glass fiber lasers and amplifiers have great applicative potential in many fields since they are key elements in the near and medium-infrared (mid-IR) wavelength range. In this paper, a review, even if not exhaustive, on amplification and lasing obtained by employing rare-earth-doped chalcogenide photonic crystal fibers is reported. Materials, devices, and feasible applications in the mid-IR are briefly mentioned. L. Mescia, F. Smektala, and F. Prudenzano Copyright © 2012 L. Mescia et al. All rights reserved. Tue, 13 Nov 2012 10:17:42 +0000 http://www.hindawi.com/journals/ijo/2012/960985/ We applied Fourier space analysis to a comprehensive study of the propagation of pulsed two-dimensional images through single and coupled image resonators. The Fourier method shows that the image can propagate through the resonator successfully as long as the spatial and temporal Fourier components of the image are within the bandwidth of the amplitude and phase transfer functions. The relevant steep dispersion of the cavity can yield delayed or advanced images. The Fourier method reproduces characteristic aspects of the experimental observations of the image propagation, and also predicts new aspects, such as the spatial image profile dependence on the observation time and the coupling strength. To demonstrate the time evolution of the experiment, space- and time-resolved image propagations were performed using a streak camera. Parvin Sultana, Takahiro Matsumoto, and Makoto Tomita Copyright © 2012 Parvin Sultana et al. All rights reserved. Thu, 01 Nov 2012 15:07:22 +0000 http://www.hindawi.com/journals/ijo/2012/120731/ Anomalous beam propagation in low index-contrast metamaterials has been analyzed. The condition for a well-collimated beam is found to be depending on the beam width and the pertinent Fourier component of the dielectric function. Guided by this condition, an ultra-compact metamaterial structure is designed to deflect a light beam at a wide angle. The structure is tolerant to structural parameter deviation and has a wide bandwidth. Jun Tan, Weiwei Song, and Wei Jiang Copyright © 2012 Jun Tan et al. All rights reserved. Wed, 26 Sep 2012 14:59:56 +0000 http://www.hindawi.com/journals/ijo/2012/879392/ Hyperbolic metamaterials can manipulate electromagnetic waves by converting evanescent waves into propagating waves and thus support light propagation without diffraction limit. In this paper, deep subwavelength focusing (or power concentration) is demonstrated both numerically and experimentally using hyperbolic metamaterials. The results verify that hyperbolic metamaterials can focus a broad collimated beam to spot size of ~λ0/6 using wired medium design for both normal and oblique incidence. The nonmagnetic design, no-cut-off operation, and preferred direction of propagation in these materials significantly reduce the attenuation in electromagnetic waves. Amanpreet Kaur, Saptarshi Banerjee, Wangshi Zhao, Jayanti Venkataraman, and Zhaolin Lu Copyright © 2012 Amanpreet Kaur et al. All rights reserved. Tue, 11 Sep 2012 08:57:06 +0000 http://www.hindawi.com/journals/ijo/2012/603083/ The unique properties of metamaterials, namely, their negative refractive index, permittivity, or permeability, have gained much recent attention. Research into these materials has led to the realization of a host of applications that may be useful to enhance optical nanolithography. A selection of materials has been examined both experimentally and theoretically to verify their support of surface plasmons, or lack thereof, in the DUV spectrum via the attenuated total reflection (ATR) method using the Kretschmann configuration. At DUV wavelengths, materials that were previously useful at mid-UV and longer wavelengths no longer act as metamaterials. Structured materials comprised of alternating layers of aluminum and aluminum oxide (Al2O3), as well as some other absorption-free dielectrics, exhibit metamaterial behavior, as do some elemental materials such as aluminum. These elemental and structured materials exhibit the best properties for use in plasmonic nanolithographic applications. Therefore, a simulator was created to examine material and thickness combinations to generate a tunable metamaterial for use in the DUV. A method for performing plasmonic interference lithography with this metamaterial has been proposed, with calculations showing the potential for half-pitch imaging resolution of 25 nm. Andrew Estroff and Bruce W. Smith Copyright © 2012 Andrew Estroff and Bruce W. Smith. All rights reserved. Sun, 09 Sep 2012 15:50:31 +0000 http://www.hindawi.com/journals/ijo/2012/486849/ We propose and theoretically investigate a novel approach for generating terahertz (THz) radiation in a standard single-mode fiber. The optical fiber is mediated by an electrostatic field, which induces an effective second-order nonlinear susceptibility via the Kerr effect. The THz generation is based on difference frequency generation (DFG). A dispersive fiber Bragg grating (FBG) is utilized to phase match the two interacting optical carriers. A ring resonator is utilized to boost the optical intensities in the biased optical fiber. A mathematical model is developed which is supported by a numerical analysis and simulations. It is shown that a wide spectrum of a tunable THz radiation can be generated, providing a proper design of the FBG and the optical carriers. Montasir Qasymeh Copyright © 2012 Montasir Qasymeh. All rights reserved. Thu, 06 Sep 2012 11:54:13 +0000 http://www.hindawi.com/journals/ijo/2012/532316/ A Green function formulism is developed to calculate the electromagnetic fields generated by sources embedded in nanostructured medium which could be represented by an effective electric permittivity tensor with finite thicknesses. The method begins with the decomposition of the generated mode into the eigenmodes in the medium, which have definite dispersions. To account the interface effect at boundaries, especially the mode conversion at the interface between anisotropic media, mode expansion method is combined into the theoretical framework. Thus, the electromagnetic wave in any given position can be gotten clearly. The formulism can provide conveniences of studying the novel properties of nanostructured metamaterials. Shunbo Li, Xiao Xiao, Bo Hou, and Weijia Wen Copyright © 2012 Shunbo Li et al. All rights reserved. Sun, 02 Sep 2012 10:46:44 +0000 http://www.hindawi.com/journals/ijo/2012/372048/ We review some of the recent research activities on plasmonic devices based on metal-dielectric-metal (MDM) stub resonators for manipulating light at the nanoscale. We first introduce slow-light subwavelength plasmonic waveguides based on plasmonic analogues of periodically loaded transmission lines and electromagnetically induced transparency. In both cases, the structures consist of a MDM waveguide side-coupled to periodic arrays of MDM stub resonators. We then introduce absorption switches consisting of a MDM plasmonic waveguide side-coupled to a MDM stub resonator filled with an active material. Yin Huang, Changjun Min, Liu Yang, and Georgios Veronis Copyright © 2012 Yin Huang et al. All rights reserved. Thu, 30 Aug 2012 13:39:31 +0000 http://www.hindawi.com/journals/ijo/2012/408067/ The temporal coherence interference properties of light as revealed by single detector intensity measurements in a Michelson-Morley interferometer (MMI) is often described in terms of classical optics. We show, in a pedagogical manner, how such features of light also can be understood in terms of a more general quantum-optics framework. If a thermal reference source is used in the MMI local oscillator port in combination with a thermal source in the signal port, the interference pattern revealed by single detector intensity measurements shows a distinctive dependence on the differences in the temperature of the two sources. A related method has actually been used to perform high-precision measurements of the cosmic microwave background radiation. The general quantum-optics framework allows us to consider any initial quantum state. As an example, we consider the interference of single photons as a tool to determine the peak angular-frequency of a single-photon pulse interfering with a single-photon reference pulse. A similar consideration for laser pulses, in terms of coherent states, leads to a different response in the detector. The MMI experimental setup is therefore an example of an optical device where one, in terms of intensity measurements, can exhibit the difference between classical and quantum-mechanical light. Ø. Langangen, A. Vaskinn, and B.-S. Skagerstam Copyright © 2012 Ø. Langangen et al. All rights reserved. Tue, 14 Aug 2012 16:55:00 +0000 http://www.hindawi.com/journals/ijo/2012/901970/ Two-dimensional arrays of particles are of great interest because of their very characteristic optical properties and numerous potential applications. Although a variety of theoretical approaches are available for the description of their properties, methods that are accurate and convenient for computational procedures are always sought. In this work, a new technique to study the diffraction of a monochromatic electromagnetic field by a two-dimensional lattice of spheres is presented. The method, based on Fourier series, can take into account an arbitrary number of terms in the multipole expansion of the field scattered by each sphere. This method has the advantage of leading to simple formulas that can be readily programmed and used as a powerful tool for nanostructure characterization. Bernard de Dormale and Vo-Van Truong Copyright © 2012 Bernard de Dormale and Vo-Van Truong. All rights reserved. Wed, 08 Aug 2012 10:04:48 +0000 http://www.hindawi.com/journals/ijo/2012/651563/ We present computational and experimental results of dust particles that can be tuned to preferentially reflect or emit IR radiation within the 8–14 μm band. The particles consist of thin metallic subwavelength gratings patterned on the surface of a simple quarter wavelength cavity. This design creates distinct IR absorption resonances by combining the plasmonic resonance of the grating with the natural resonance of the cavity. We show that the resonance peaks are easily tuned by varying either the geometry of the grating or the thickness of the cavity. Here, we present a computational design algorithm along with experimental results that validate the design methodology. Mark Mirotznik, William Beck, Kimberly Olver, John Little, and Peter Pa Copyright © 2012 Mark Mirotznik et al. All rights reserved. Tue, 31 Jul 2012 08:46:45 +0000 http://www.hindawi.com/journals/ijo/2012/258013/ With the fast development of microfabrication technology and advanced computational tools, nanophotonics has been widely studied for high-speed data transmission, sensitive optical detection, manipulation of ultrasmall objects, and visualization of nanoscale patterns. As an important branch of nanophotonics, plasmonics has enabled light-matter interactions at a deep subwavelength length scale. Plasmonics, or surface plasmon based photonics, focus on how to exploit the optical property of metals with abundant free electrons and hence negative permittivity. The oscillation of free electrons, when properly driven by electromagnetic waves, would form plasmon-polaritons in the vicinity of metal surfaces and potentially result in extreme light confinement. The objective of this article is to review the progress of subwavelength or deep subwavelength plasmonic waveguides, and fabrication techniques of plasmonic materials. Ruoxi Yang and Zhaolin Lu Copyright © 2012 Ruoxi Yang and Zhaolin Lu. All rights reserved. Sun, 15 Jul 2012 16:05:01 +0000 http://www.hindawi.com/journals/ijo/2012/152937/ With the purpose to compare the physical features of the electromagnetic field, we describe the synthesis of optical singularities propagating in the free space and on a metal surface. In both cases the electromagnetic field has a slit-shaped curve as a boundary condition, and the singularities correspond to a shock wave that is a consequence of the curvature of the slit curve. As prototypes, we generate singularities that correspond to fold and cusped regions. We show that singularities in free space may generate bifurcation effects while plasmon fields do not generate these kinds of effects. Experimental results for free-space propagation are presented and for surface plasmon fields, computer simulations are shown. Gabriel Martínez-Niconoff, P. Martinez-Vara, G. Diaz-Gonzalez, J. Silva-Barranco, and A. Carbajal-Domínguez Copyright © 2012 Gabriel Martínez-Niconoff et al. All rights reserved. Sun, 15 Jul 2012 14:08:33 +0000 http://www.hindawi.com/journals/ijo/2012/808679/ An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is designed and optimized. A dedicated 3D numerical model, which exploits the coupled mode theory and the rate equations, is used. The main transitions among the erbium energy levels, the amplified spontaneous emission, and the most important secondary transitions pertaining to the ion-ion interactions have been considered. Both the pump and signal beams are efficiently injected and obtained by a suitable design of the taper angle and the fiber-microsphere gap. Moreover, a good overlapping between the optical signals and the rare-earth-doped region is also obtained. In order to evaluate the amplifier performance in reduced computational time, the doped area is partitioned in sectors. The obtained simulation results highlight that a high-efficiency midinfrared amplification can be obtained by using a quite small microsphere. P. Bia, A. Di Tommaso, and M. De Sario Copyright © 2012 P. Bia et al. All rights reserved. Tue, 10 Jul 2012 11:10:54 +0000 http://www.hindawi.com/journals/ijo/2012/238367/ This paper tries to investigate a novel polishing technology with high efficiency and nice surface quality for sapphire crystal that has high hardness, wear resistance, and chemical stability. A Q-switched 355 nm ultraviolet laser with nanosecond pulses was set up and used to polish sapphire substrate in different conditions in this paper. Surface roughness 𝑅𝑎 of polished sapphire was measured with surface profiler, and the surface topography was observed with scanning electronic microscope. The effects of processing parameters as laser energy, pulse repetition rate, scanning speed, incident angle, scanning patterns, and initial surface conditions on surface roughness were analyzed. X. Wei, X. Z. Xie, W. Hu, and J. F. Huang Copyright © 2012 X. Wei et al. All rights reserved. Mon, 09 Jul 2012 08:16:02 +0000 http://www.hindawi.com/journals/ijo/2012/146396/ We analyze the effective opening of finite bands of inhibited transmission in realistic systems excited by actual out-of-plane sources. We first observe how the excitation of surface plasmon polaritons in one-dimensional arrays of metal slits depends on the angle of incidence of the source field. Then, the well-known grating-coupling equation is revised in order to find an asymmetric structure with equivalent parameters which, under perfectly normal excitation, is able to exhibit surface plasmon polariton modes at the same wavelengths of the original structure which undergoes a nonorthogonal incidence of the light. In this way we demonstrate through finite-element simulations that a realistic system, probed by a source beam in a finite light-cone, can be effectively decomposed in several equivalent systems with different physical and geometrical parameters, with results in the enlargement of the theoretically expected punctual minimum of transmission. Roberto Marani, Marco Grande, Vincenzo Petruzzelli, and Antonella D'Orazio Copyright © 2012 Roberto Marani et al. All rights reserved. Sun, 08 Jul 2012 08:33:32 +0000 http://www.hindawi.com/journals/ijo/2012/648741/ It is shown that the low-temperature plasma near-thermodynamic equilibrium cannot be classical because of a quantum nature of the longitudinal electromagnetic field and electron interaction with Rayleigh-Jeans distribution of Langmuir waves. The theory requires introduction of a dimensionless quantum charge whose value is greater than unity leading to a liquid-like behavior of the plasma. Boris Alexandrovich Veklenko Copyright © 2012 Boris Alexandrovich Veklenko. All rights reserved. Wed, 06 Jun 2012 08:42:05 +0000 http://www.hindawi.com/journals/ijo/2012/130517/ Interferometric switching as a routing method in sequence of coupled optical microresonators is explored. Mach-Zhender interferometry is extended to systems of side-coupled integrated sequences of resonators (SCISSORs) and coupled resonators optical waveguides (CROWs). We generalized Coupled Mode Theory (CMT) to a system of three coupled waveguides. The two bus interferometric switching functions of SCISSOR and CROW resonant structures are investigated. A novel switching device based on three input phase modulation ports is presented. This device displays a wide range of switching behaviors which might lead to new interesting applications. Marco Masi, Mattia Mancinelli, Paolo Bettotti, and Lorenzo Pavesi Copyright © 2012 Marco Masi et al. All rights reserved. Mon, 04 Jun 2012 10:13:57 +0000 http://www.hindawi.com/journals/ijo/2012/308628/ Nanguang Chen, Baohong Yuan, and Javier A. Jo Copyright © 2012 Nanguang Chen et al. All rights reserved. Wed, 23 May 2012 07:56:27 +0000 http://www.hindawi.com/journals/ijo/2012/361818/ In deep penetration laser welding, a keyhole is formed in the material. Based on an experimentally obtained bending keyhole from low- and medium-speed laser penetration welding of glass, the keyhole profiles in both the symmetric plane are determined by polynomial fitting. Then, a 3D bending keyhole is reconstructed under the assumption of circular cross-section of the keyhole at each keyhole depth. In this paper, the behavior of focused Gaussian laser beam in the keyhole is analyzed by tracing a ray of light using Gaussian optics theory, the Fresnel absorption and multiple reflections in the keyhole are systematically studied, and the laser intensities absorbed on the keyhole walls are calculated. Finally, the formation mechanism of the keyhole is deduced. Xiangzhong Jin, Yuanyong Cheng, Licheng Zeng, Yufeng Zou, and Honggui Zhang Copyright © 2012 Xiangzhong Jin et al. All rights reserved. Wed, 16 May 2012 14:29:11 +0000 http://www.hindawi.com/journals/ijo/2012/530648/ Sonia Boscolo, Juan Diego Ania Castañón, Christophe Finot, and Miguel González Herráez Copyright © 2012 Sonia Boscolo et al. All rights reserved. Mon, 30 Apr 2012 08:24:00 +0000 http://www.hindawi.com/journals/ijo/2012/365109/ Nicolas Bonod, Alexandre Bouhelier, A. Femius Koenderink, and Ali Passian Copyright © 2012 Nicolas Bonod et al. All rights reserved. Sun, 29 Apr 2012 10:53:49 +0000 http://www.hindawi.com/journals/ijo/2012/764084/ The adjustable gain-clamped semiconductor optical amplifier (AGC-SOA) uses two SOAs in a ring-cavity topology: one to amplify the signal and the other to control the gain. The device was designed to maximize the output saturated power while adjusting gain to regulate power differences between packets without loss of linearity. This type of subsystem can be used for power equalisation and linear amplification in packet-based dynamic systems such as passive optical networks (PONs). A detailed theoretical model is presented in this paper to simulate the operation of the AGC-SOA, which gives a better understanding of the underlying gain clamping mechanics. Simulations and comparisons with steady-state and dynamic gain modulation experimental performance are given which validate the model. Lin Liu, Craig Michie, Anthony E. Kelly, and Ivan Andonovic Copyright © 2012 Lin Liu et al. All rights reserved. Thu, 26 Apr 2012 12:08:31 +0000 http://www.hindawi.com/journals/ijo/2012/627018/ We highlight the feasibility of experimental implementation of both inverted and noninverted wavelength conversion, 2R regeneration, and all-optical logic functions, such as OR, NOR, XOR, and XNOR optical gates by exploiting the self-polarization rotation in a semiconductor optical amplifier (SOA) device without changing the setup configuration. Switching between each optical function is done by only adjusting the input optical power level. In order to allow optimum control and preserve the polarization state of the injected and collected signals, the polarimetric measures have been carried out in free space. Youssef Said and Houria Rezig Copyright © 2012 Youssef Said and Houria Rezig. All rights reserved. Wed, 18 Apr 2012 12:01:44 +0000 http://www.hindawi.com/journals/ijo/2012/431826/ Higher-order squeezing in different optical processes such as seven-wave mixing and five-wave mixing has been studied. The total noise of a field state is a measure of the fluctuations of the field amplitude. It is shown that the minimum total noise (𝑇min) of a higher-order squeezed state always increases with the increase in nonclassicality associated with higher-order squeezing. Thus, from 𝑇min, one can conclude that highly nonclassical states have large amplitude fluctuations. Savita Gill, Sunil Rani, and Nafa Singh Copyright © 2012 Savita Gill et al. All rights reserved.