Search results for "ELECTRONICS"
showing 10 items of 4340 documents
A Novel Method Of Measuring Light Absorption On A Self-Assembled Single Quantum Dot
2005
Abstract. We present a novel method by wich excitonic interband optical transitions within single InAs self-assembled quantum dots can be directly observed in a transmission experiment. Due to the extremely high resolution of the tecnique, individual peaks associated to single exciton absorption resonances in single quantum dots can be spectrally resolved. Using this technique we investigate the oscillator strength, homogeneous linewidth and fine structure splitting in a collection of such individual resonances.
Evaluation of performance of a hybrid electro-optic directional coupler and a Mach–Zehnder switch
2017
The efficiency of an electro-optic (EO) directional coupler (DC) and a Mach–Zehnder (MZ) switch is discussed. The specific designs employ a passive waveguide core and an EO cladding. The performance of a DC switch was evaluated by numerical methods, namely coupled mode theory (CMT), eigenmode expansion (EME) method, and beam envelope method. Using the CMT and EME methods, it is shown that in the DC with a passive waveguide core and EO cladding at certain waveguide parameters the switching effect does not take place. The effect is demonstrated for the first time and suggests that careful optimization of the DC switch should be done before experimental realization of the device. The efficienc…
Nonlinear Current Generation in Degenerate Semiconductors Embedded in Constant and Low-Frequency Electric Fields
2006
The explicit analytical forms of nonlinear currents in degenerate semiconductors serving as sources of coherent radiation in the wavelength millimetric and submillimetric ranges are established.
Ultrafast hybrid plasmonics
2008
Abstract We review our recent studies of electromagnetic coupling and associated temporal dynamics of molecular excitations with plasmonic resonances supported by either localized or extended planar geometries. We focus on coherent interactions between plasmon resonances and molecular excitations, which are experimentally challenging due to the very short (∼10–100 fs) coherence times of plasmons. Recent experimental results and theoretical analysis for observing and controlling coherences between molecular excitations and plasmonic polarizations are shown. Advances will explore new directions in ultrafast coherent control of molecular excited states and energy dissipation processes, as well…
Plasmonic stratified devices for superlensing in the self-focusing regime
2012
We show that diffraction-management of subwavelength scattered fields assisted by metallodielectric heterostructures leads to superresolving imaging. An accurate design of a passive multilayered compound provides nearly aberration-free images with subwavelength resolution out of the canalization regime even using optical paths longer than a wavelength.
Multimodal reflectivity of CRIGF filters: First experimental observation and modelling
2015
International audience; Cavity Resonator Integrated Guided-mode Resonance Filter (CRIGF) are a new class of filtering reflectors whose selected wavelength and spectral width are independent of the angle of incidence unlike GMRF. These particular properties allow both compactness and a high angular acceptance. However, ours studies show that CRIGFs offer simultaneously spectral and modal filtering and we evidence high-spatial-order reflected modes. In this paper, we will present characterization of the spectral and spatial profile that demonstrates the existence of these high-order modes. In addition, we will present a model based on the physical understanding of implied phenomena to explain…
Semilinear photorefractive oscillator with reflection gratings
2003
We present results of calculation of the steady-state output characteristics for a semilinear photorefractive oscillator pumped with two independent counterpropagating waves when the reflection grating is operative and compare them with measurements made with a BaTiO3:Co.
Self-trapping of speckled light beams
2008
A speckle beam of light breaks up into small fragments as it propagates in a standard self-focusing nonlinear material. Now, by exploiting the non-local thermal response of a material, it is possible to trap a speckle beam in a self-induced waveguide.
White-light array generation with a diffractive lenslet array
1999
Abstract In this paper we present two different optical configurations providing a white-light array generator based on a diffractive lenslet array (DLA). In both cases, starting from a white-light point source we achieve a regularly spaced set of sharp light spots by use of a single DLA and a small number of extra lenses (only one or two). The first optical system permits us to change the separation between the intensity peaks in a tunable way. The second is very compact and consists only of diffractive lens elements. The key question in both set-ups is the use of achromatic Fourier-transform methods. In this way, we achieve, in a first-order approximation, the superposition of the chromat…
Buildup of terahertz vector dark-soliton trains from induced modulation instability in highly birefringent optical fiber.
2007
We present the experimental observation of generation of vector dark-soliton pulse trains with terahertz repetition rates in the normal dispersion regime of an optical fiber. The polarization solitons build up from induced cross-phase modulation instability of two orthogonal pumps in a highly birefringent fiber.