1,721,018 research outputs found
Full three-dimensional wavelength-scale plasmomechanical resonator
No full textPlasmomechanical systems have received considerable interest in mediating the strong interaction between the optical field and mechanical motion. However, typical plasmomechanical systems based on mechanical oscillators that are significantly larger than the wavelength of light do not take full advantage of the optical field concentration beyond the optical diffraction limit of the employed plasmonic resonators. Here we present a full three-dimensional wavelength-scale plasmomechanical resonator consisting of a plasmonic nano-antenna and a hydrogen silsesquioxane nano-wall. The experimental results demonstrated the precise detection of longitudinal mechanical oscillation on a picometer scale, and we investigated the tunability and thermoelastic effect of the mechanical resonance. (C) 2021 Optical Society of America
파장 정도 크기를 가진 광결정 레이저에 관한 연구
No full text학위논문(박사) - 한국과학기술원 : 물리학과, 2009.2, [ v, 135 p. ]The smallest possible laser has long been a challenging and exciting issue in the laser and quantum optics communities. Owing to advances in semiconductor crystal growth and fabrication techniques, lasing actions in various micrometer-size cavities in solids have been successfully performed. The size of semiconductor micro-lasers has become truly wavelength-scale as witnessed by the demonstration of photonic crystal nano-cavities. Particularly, high-quality photonic crystal cavities down to the wavelength scale offer the distinct possibility of a thresholdless laser and a single photon source. Strong coupling phenomena have also been experimentally observed in photonic crystal cavities containing semiconductor quantum dots. However, a number of issues, such as a fully three-dimensional analysis of light-matter interaction in photonic crystal cavities, an electrically driven lasing operation for a practical device, and spectral and spatial tuning of the resonant modes of the photonic crystal, remain to be addressed before it is possible to practically realize these high-performance optical applications. In this thesis, solutions for the issues are proposed and demonstrated, representing small but meaningful steps toward the ultimate creation of quantum optical devices using wavelength-scale photonic crystal cavities.
First, a three-dimensional finite-difference time-domain method that can handle dispersive and dynamic nonlinear-gain media such as semiconductor quantum wells and quantum dots is proposed and realized. The effect of carrier diffusion is included through the formulation of laser rate equations. Through this three-dimensional nonlinear gain FDTD method, rich laser-dynamics behaviors, such as the lasing threshold, the relaxation oscillations, and the spatial hole burning, are directly observed from a hexapole mode. Also examined and measured are interesting characteristics of Rabi splitting between a wavelength-scale PhC cavity mode and a single qua...한국과학기술원 : 물리학과
Nonlinear dispersive three-dimensional finite-difference time-domain analysis for photonic-crystal lasers
Full text linkThe three-dimensional finite-difference time-domain method that can handle dispersive and dynamic nonlinear-gain media is proposed and realized. The effect of carrier diffusion is included through the laser rate equations. Through this three-dimensional nonlinear gain FDTD method, rich laser-dynamics behaviors, such as the lasing threshold, the relaxation oscillation, and the spatial hole burning, are directly observed from a hexapole mode. (c) 2005 Optical Society of America.This work was supported in part by MOST under the National R&D Project for Nanoscience
and Technology and by the MIC-IITA under the ITRC-20050C1090-0502-0b029 program
Resonant magneto-optic Kerr effects of a single Ni nanorod in the Mie scattering regime
No full textWe present a systematic, theoretical investigation of the polar magneto-optical (MO) Kerr effects of a single Ni nanorod in the Mie regime. The MO Kerr rotation, ellipticity, amplitude ratio, and phase shift are calculated as a function of the length and width of the nanorod. The electric field amplitude ratio of the MO Kerr effect is locally maximized when the nanorod supports a plasmonic resonance in the polarization state orthogonal to the incident light. The plasmonic resonances directly induced by the incident light do not enhance the amplitude ratio. In the Mie regime, multiple local maxima of the MO Kerr activity are supported by the resonant modes with different modal characteristics. From the viewpoint of first-order perturbation analysis, the spatial overlap between the incident-light-induced electric field and the Green function determines the local maxima. (C) 2016 Optical Society of Americ
Reconfigurable Periodic Liquid Crystal Defect Array via Modulation of Electric Field
No full textTopological defects in liquid crystal (LC) phases have been considered critical from the areas in topology and self-assembly, as well as in applications such as optical vortex generation, particle manipulation system, and template for material micropatterning. An approach for generating and modulating various patterns of LC defects is presented in a single cell by varying the electrode configurations. Periodic LC defect arrays including -1 topological defect in the nematic phase can be achieved by simply adjusting crossed electrodes. Specifically, the fourfold symmetric -1 defect pattern is used as a vortex beam generator and a particle trapping agent with control either of the frequency of the applied electric field or the temperature. The approach suggested here would be beneficial to extend the use of LC patterns in lithographic tools and optoelectronic devices.
Elimination of cross-talk in waveguide intersections of triangular lattice photonic crystals
No full textWe design an intersection for crossing waveguides in triangular lattice photonic crystals with cross-talk smaller than 10(-5). The cross-talk to the transverse waveguides is suppressed by symmetry mismatch between the cavity mode and the waveguide mode or by the mode-gap effect induced by air hole radius modulation of the waveguides. The transmission behavior of the crossing waveguides are illustrated by numerical simulations through finite difference time domain method. (C) 2008 Optical Society of America.The authors would like to thank Thomas Sünner for fruitful discussions
Reconfigurable microfiber-coupled photonic crystal resonator
Full text linkWe propose and demonstrate reconfigurable microfiber-coupled photonic crystal (PhC) lasers. In this generic configuration, the position of a PhC resonator can be defined (and redefined) repeatedly by simply relocating a curved microfiber along the linear PhC waveguide. In the proximity of the PhC waveguide in contact with the microfiber, the cutoff frequency (effective index) of the PhC waveguide becomes smaller (larger) than that of a bare PhC waveguide. Accordingly, when a curved microfiber is in contact with the PhC waveguide, a linear PhC resonator having Gaussian-shaped potential well is formed. Experimentally we confirm the formation of the reconfigurable resonator by observing laser operation slightly below three available band edges. (C) 2007 Optical Society of America
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