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Analysis of tip-localized surface plasmon resonances in periodic arrays of gold nanowires with triangular cross section

Ricardo Téllez-Limón, Mickaël Fevrier, Aniello Apuzzo, Rafael Salas-Montiel, and Sylvain Blaize

Doc ID: 297858 Received 14 Jun 2017; Accepted 20 Aug 2017; Posted 21 Aug 2017  View: PDF

Abstract: In this contribution, we study the tip-enhancement of localized surface plasmons in periodic arrays of gold nanowires with triangular cross section under different illumination configurations. We found that the plasmonic resonance in a single nanowire is excited with a transverse magnetic (TM) plane wave impinging from the substrate at the critical angle, whereas grazing angles are required for the excitation of resonant propagating modes in periodic arrays of triangular-shaped nanowires. Moreover, we foundthat resonant plasmonic quasi-Bloch modes are efficiently excited with the fundamental TM mode of a dielectric waveguide placed underneath the array. The integrated plasmonic structure allows a strong enhancement of the electromagnetic field at the tip of the nanowires, hence its potential application in the development of new nanophotonic devices.

On quantum approach to modeling of plasmon photovoltaic effect

Katarzyna Kluczyk, Witold Jacak, and Christin David

Doc ID: 297848 Received 14 Jun 2017; Accepted 18 Aug 2017; Posted 21 Aug 2017  View: PDF

Abstract: Surface plasmons in metallic nanostructures including metallically nano-modified solar cells are conventionally studied and modeled by application of the Mie approach to plasmons or by the finite element solution of differential Maxwell equations with imposed boundary and material constraints (e.g., upon commercial Comsol software-system). Both approaches are essentially classical ones and neglect quantum particularities related to plasmon excitations in metallic components. We demonstrate that these quantum plasmon effects are of crucial importance especially in theoretical simulations of plasmon-aided photovoltaic phenomena. Quantum corrections considerably improve both the Mie and Comsol approches in this case. We present the semiclassical random phase approximation description of plasmons in metallic nanoparticle and apply the quantum Fermi golden rule scheme to assess the sun-light energy transfer to the semiconductor solar cell mediated by surface plasmons in metallic nanoparticles deposited on the top of the battery. In addition, short-ranged electron-electron interaction in metals is discussed in the framework of the semiclassical hydrodynamic model. The significance of the related quantum corrections are illustrated by the quantumly improved Comsol simulations.

Photon superbunching of classical light in the Hanbury Brown-Twiss interferometer

Bin Bai, Jianbin Liu, Yu Zhou, Huaibin Zheng, Hui Chen, Songlin Zhang, Yuchen He, fuli li, and Zhuo Xu

Doc ID: 298307 Received 22 Jun 2017; Accepted 17 Aug 2017; Posted 21 Aug 2017  View: PDF

Abstract: Two-photon superbunching of classical light is observed with single-mode continuous-wave laser light in a linear optical system. By adding more two-photon paths via rotating ground glasses, pinholes, lens, etc, g²(0) = 7.10 ± 0.07 is experimentally observed. The second-order temporal coherence function of the superbunching pseudothermal light is theoretically and experimentally studied in detail. It is predicted that the degree of coherence can be increased dramatically by adding more multi-photon paths. For instance, the degree of the second- and third-order coherence of the superbunching pseudothermal light with five rotating ground glasses can reach 32 and 7776, respectively. The results are helpful to understand the physics of superbunching and to improve the visibility of thermal light ghost imaging.

Super Directive Yagi-Uda Nano-Antennas with Ellipsoid Reflector for Optimal Radiation Emission

Korany Mahmoud, MOHAMED HUSSEIN, Mohamed Hameed, and Salah Obayya

Doc ID: 293228 Received 20 Apr 2017; Accepted 13 Aug 2017; Posted 15 Aug 2017  View: PDF

Abstract: In this paper, the optimal designs of silicon Yagi-Uda nanoantennas (NAs) with ellipsoid reflector have been proposed and analyzed using 3D finite difference time domain (FDTD) method. Combination of nanospheres, nanowires and ellipsoid reflectors has been employed to enhance the antenna directivity. The nanoantenna geometrical parameters are optimized using particle swarm optimization (PSO) algorithm. The optimized spherical NA with ellipsoid reflector shows high directivity of 21.67 which is higher than the conventional counterpart by 80.58 %. This enhancement is attributed to the different supported modes by the ellipsoid reflector which increases the forward radiation and suppresses the backward one. Further, the optimized nanowires design with ellipsoid reflector has achieved a directivity of .4. In addition, the radiation efficiency has been increased to 80.2% and 75.9% for optimized spherical and nanowires antenna, respectively. This enhancement is attributed to the efficient coupling between array elements as well as reduced side and back-lobe levels.

Multispectral sparkling of microbubbles with focused femtosecond las

Raymond Ooi and Ahmed Sanny

Doc ID: 295792 Received 11 May 2017; Accepted 13 Aug 2017; Posted 15 Aug 2017  View: PDF

Abstract: Nonlinear interactions of focused femtosecond laser with water can provideinteresting optical phenomena. We observed intense scattered lights withmulti colors at the surface of microbubbles formed by focused femtosecondlaser inside the water. This optical scattering phenomena is found for thefirst time since the invention of femtosecond laser. The bubbles are formedrapidly before the emissions of colorful sparkling lights at a back-sidepoint of water-vapor interface of the microbubbles. Analysis of thenonlinear optical processes, particularly spectral blueshift and broadeningwith filamentation hot spots in the water explains the effect ofmultispectral scattering. This work may provide a new method for visualizingthe filamentation hot spots and the corresponding frequency components inthe focusing region by making use of the strong scattering at thewater-vapor interface of the microbubbles.

Laser frequency stabilization by bichromatic saturation absorption spectroscopy

Thorsten Peters, Thomas Halfmann, Tim Lellinger, and Genko Genov

Doc ID: 296350 Received 19 May 2017; Accepted 10 Aug 2017; Posted 15 Aug 2017  View: PDF

Abstract: We present and analyze a bichromatic version of the well-known saturation absorption spectroscopy technique used to stabilize lasers to atomic resonances without Doppler broadening. We show that the spectroscopic properties can be transferred between two transitions at very different wavelengths by spectral hole burning in a Doppler-broadened atomic ensemble. Specifically, we demonstrate that this technique can be used to stabilize a laser to the D₁ line of ⁸⁷Rb by obtaining a saturation absorption spectrum with a strong pump laser stabilized to the D₂ line. This allows for more freedom in the choice of the probe laser frequency offsets, compared to conventional saturation absorption spectroscopy. We compare our experimental results to an analytical model and numerical results based on rate equations.

Nonlocal response of tunable photonic metamaterials with semiconductor inclusions

Anatolii Konovalenko and Felipe Pérez-Rodríguez

Doc ID: 290659 Received 13 Mar 2017; Accepted 10 Aug 2017; Posted 15 Aug 2017  View: PDF

Abstract: The effective parameters of homogenized photonic crystals, having a semiconductor bar in the unit cell, are calculated and analyzed. The applied homogenization theory is based on the Fourier formalism within the form-factor division approach. The calculated effective parameters, namely the components of the effective permittivity tensor, are nonlocal since they depend not only on frequency, but also on the wave vector. Using the nonlocal effective parameters, the complex dispersion relation for photonics modes propagating in the periodic semiconductor-dielectric array can be described even beyond the long wavelength limit. We have analyzed the temperature dependence of the nonlocal effective parameters for photonic metamaterials composed of InSb square bars in a silica-glass host matrix. In the case of continuous (infinitely long) bars the metamaterial exhibits plasma-like behavior with a temperature-dependent effective plasma frequency in the THz range. For the case of cut semiconductor bars, the metamaterial behaves as a dielectric in the lowest frequency band, whose width can also be tuned by varying the temperature.

Suppression of Four-Wave Mixing in Hot Rubidium Vapor Using Ladder Scheme Raman Absorption

Irina Novikova, Nikunj Prajapati, and Gleb Romanov

Doc ID: 298003 Received 14 Jun 2017; Accepted 08 Aug 2017; Posted 10 Aug 2017  View: PDF

Abstract: We experimentally investigate the effectiveness of the four-wave mixing suppression in a double-A interaction scheme by introducing an additional ladder-type two-photon Raman absorption resonance for one of the optical fields. We propose several possible interaction configurations involving either one or two isotopes of Rb, and experimentally demonstrate the possibility of efficient four-wave mixing suppression in both EIT and far-detuned Raman cases.

LOCALIZED OPTICAL STATES IN A DEFECT-CONTAINING LIQUID-CRYSTAL STRUCTURE ADJACENT TO THE METAL

Maxim Pyatnov, Stepan Vetrov, and Ivan Timofeev

Doc ID: 300939 Received 26 Jun 2017; Accepted 05 Aug 2017; Posted 07 Aug 2017  View: PDF

Abstract: We investigated a defect-containing cholesteric liquid crystal adjacent a metal layer. The possibility of existence of the localized optical states with the maximum field intensity at the interface between the metal and cholesteric liquid crystal is theoretically grounded. It is established that the localization occurs at almost any defect thicknesses rather than only at the half-wave thickness, at which the loss of the polarization dependence of diffraction reflection and the absence of field localization are observed for the structure without the metallic layer. It is demonstrated that the spectral properties can be controlled by external fields affecting the liquid crystal. At large thicknesses of the cholesteric liquid crystal between the defect and metallic layer, the spectrum contains the pronounced peaks corresponding to the edge modes. The results obtained open new opportunities for controlling the transmittance spectrum, polarization and localization of light in optoelectronic elements based on the investigated system.

Tunable narrow-band plasmonic resonances in electromagnetically-induced-transparency media

David Ziemkiewicz, Karolina Slowik, and Sylwia Zielińska-Raczyńska

Doc ID: 294571 Received 24 Apr 2017; Accepted 04 Aug 2017; Posted 07 Aug 2017  View: PDF

Abstract: The spectral response of a plasmonic nanostructure may heavily depend on the refractive index of its surroundings. The key idea of this paper is to control this response by coherent optical means, i.e. with an optically controlled electromagnetically-induced-transparency medium. In such environment, an external laser provides a knob to shift the position of plasmonic resonances without the need to change the geometry of the nanostructure. Additionally, the setup can be exploited to excite narrow-band surface plasmon polaritons.

Field Control With Binary Aperiodic Nanostructures

Yu-Chun Hsueh and Kevin Webb

Doc ID: 297783 Received 09 Jun 2017; Accepted 04 Aug 2017; Posted 07 Aug 2017  View: PDF

Abstract: Aperiodic, irregular structures offer a large number of degrees of freedom relative to periodic or quasi-periodic systems and hence the opportunity for more control over electromagnetic fields. The challenge is to understand the relation between structure and material and the possible response, as measured by achievable scattered field as a function of position and frequency. With this information, basic guidelines could become available to facilitate a computational design process. Having this goal in mind, near-field through far-field control is appraised through a multivariate statistical analysis of example binary two-dimensional nanostructured aperiodic material arrangements. The total variance and significant rank of the transmission matrix, equivalent to the field correlation at the detector plane in the situations treated, yields quantitative measures of the degree of control related to size, material properties, and material spatial decomposition. This analysis provides sensitivity information relevantfor the realization of aperiodic structures that can control light as a function of position and frequency in new ways.

Optical Rectification Coefficients of Cylindrical Quantum Dots: Rashba Spin-Orbit Interaction Effects

mehdi solaimani, Leila Lavaei, and seyed mohammad ali aleomraninejad

Doc ID: 296154 Received 23 May 2017; Accepted 30 Jul 2017; Posted 31 Jul 2017  View: PDF

Abstract: We numerically investigate the optical rectification coefficients (ORCs), spin density distributions and electronic properties of cylindrical quantum dots in the presence of Rashba spin-orbit interactions. Effects of spin-orbit interaction strength, effective mass and quantum dot radius are studied. The resulting coupled differential equations are solved by using a blocked Hamiltonian approach, in which the enlarged Hamiltonian matrix elements are obtained through a finite-difference discretization schema. We observe that in quantum dots with small radii, the energy dependence on effective mass is so important. We can also control the spin density and also probability density distributions by means of the effective mass and quantum dot radius. By increasing the Rashba parameter, a red shift occurs in the optical rectification coefficient peak positions. This red shift is greater in systems with greater effective masses. Finally, for a fixed Rashba parameter, by increasing the effective mass, the ORC peak positions undertake a red shift.

Larger enhancement in four-wave mixing from graphene embedded in one-dimensional photonic crystals

Lei Wang, Tiecheng Wang, Shihao Zhang, Xie Ping, and Xiangdong Zhang

Doc ID: 296271 Received 19 May 2017; Accepted 30 Jul 2017; Posted 03 Aug 2017  View: PDF

Abstract: We demonstrate theoretically that the efficiency of four-wave mixing (FWM) can be enhanced more than several orders in monolayer graphene by inserting it in a properly designed photonic crystal (PC). Two kinds of cases are considered. One is the monolayer graphene embedded in the defect PC, the other is a stack of monolayer graphene in the dielectric multilayer structure. It is found that larger enhancement of the efficiency in the FWM from the monolayer graphene can be obtained in two cases. Such an effective enhancement utilizes the improved field localization within the defect state or at the band-edge state. Due to the presence of feedback mechanism at each interface of the multilayer, we demonstrate that the tunable phase conjugation by an external voltage can be effectively generated when only one pump wave is used.

Next nearest neighbor resonance coupling and exceptional singularities in degenerate optical microcavities

Somnath Ghosh, Arnab laha, and Prof. Abhijit Biswas

Doc ID: 294561 Received 26 Apr 2017; Accepted 15 Jun 2017; Posted 16 Aug 2017  View: PDF

Abstract: We report a specially configured non-Hermitian optical microcavity, imposing spatially imbalanced gain-loss profile, to host an exclusively proposed next nearest neighbor resonances coupling scheme. Adopting scattering matrix (S-matrix) formalism, the effect of interplay between such proposed resonance interactions and the incorporated non-Hermiticity in the microcavity is analyzed drawing a special attention to the existence of hidden singularities, namely exceptional points (EP); where at least two coupled resonances coalesce. We establish adiabatic flip-of-states phenomena of the coupled resonances in the complex frequency plane (k-plane) which is essentially an outcome of the fact that the respective EP is being encircled in system parameter plane. Encountering such multiple EPs, the robustness of flip-of-states phenomena has been analyzed via continuous tuning of coupling parameters along a special hidden singular line which connects all the EPs in the cavity. Such a numerically devised cavity, incorporating the exclusive next neighbor coupling scheme, has been designed for the first time to study the unconventional optical phenomena in the vicinity of EPs.

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