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Finite-size effects occurring for quasi-bound states in the continuum (qBIC) formed in symmetric and asymmetric all-dielectric waveguide grating couplers are investigated using numerical simulations for different configuration parameters.…

Optics · Physics 2025-02-11 Torgom Yezekyan , Roza Gabrielyan , Sergey I. Bozhevolnyi

Bragg spectroscopy is used to measure excitations of a trapped, quantum-degenerate gas of 87Rb atoms in a 3-dimensional optical lattice. The measurements are carried out over a range of optical lattice depths in the superfluid phase of the…

Other Condensed Matter · Physics 2015-05-13 X. Du , Shoupu Wan , Emek Yesilada , C. Ryu , D. J. Heinzen , Z. X. Liang , Biao Wu

A perfectly collimated beam can be spread out by multiple scattering, creating a speckle pattern and increasing the etendue of the system. Standard optical systems conserve etendue, and thus are unable to reverse the process by transforming…

Optics · Physics 2021-07-23 Alba M. Paniagua-Diaz , William L. Barnes , Jacopo Bertolotti

Quantum fluctuations of optical fiber Bragg grating solitons are investigated numerically by the back-propagation method. It is found for the first time that the bandgap effects of the grating act as a nonlinear filter and cause the soliton…

Quantum Physics · Physics 2007-05-23 Ray-Kuang Lee , Yinchieh Lai

Brillouin enhanced four wave mixing in the form of a Brillouin dynamic grating (BDG) enables a uniquely tunable filter, whose properties can be tuned by purely optical means. This makes the BDG a valuable tool in microwave photonics (MWP).…

We present a microscopic description of dressed four wave mixing (4WM) demonstrating spectral control of quantum correlations. Starting from a double $\Lambda$ model for a single pump 4WM, we include a dressing field coupling the excited…

Quantum Physics · Physics 2022-01-27 A. Montaña Guerrero , R. L. Rincon Celis , M. Martinelli , H. M. Florez

Stimulated Brillouin scattering (SBS) has many applications, for example, in sensing, microwave photonics and signal processing. Here we report the first experimental study of SBS in chiral photonic crystal fiber (PCF), which displays…

We present a new technique to synthesize high-power single-cycle pulses in the visible and ultraviolet ranges by coherent superposition of a multiband octave-spanning spectrum obtained by highly-nondegenerate cascaded four-wave mixing of…

Optics · Physics 2015-05-13 Rosa Weigand , J. T. Mendonca , Helder M. Crespo

We describe a method for non-degenerate four-wave mixing in a cold sample of 4-level atoms. An integral part of the four-wave mixing process is a collective instability which spontaneously generates a periodic density modulation in the cold…

Quantum Physics · Physics 2016-09-08 G. R. M. Robb , B. W. J. McNeil

The presence of multiple bipartite entangled modes in squeezed states generated by four wave mixing in atomic vapors enables ultra-trace sensing, imaging, and metrology applications that are impossible to achieve with single-spatial-mode…

Quantum Physics · Physics 2015-12-31 B. J. Lawrie , R. C. Pooser , N. Otterstrom

Wavefront shaping allows for ultimate control of light propagation in multiple-scattering media by adaptive manipulation of incident waves. We shine two separate wavefront-shaped beams on a layer of dry white paint to create two enhanced…

Optics · Physics 2014-08-11 S. R. Huisman , T. J. Huisman , S. A. Goorden , A. P. Mosk , P. W. H. Pinkse

We investigate an extended version of the Bragg reflection waveguide (BRW) with air gaps as one of the layers. This design has the potential of drastically simplifying the epitaxial structure for integrated nonlinear optical elements at the…

Optics · Physics 2015-06-17 Benedikt Pressl , Gregor Weihs

We explore theoretically the feasibility of using frequency conversion by sum- or difference-frequency generation, enabled by three- wave-mixing, for selectively multiplexing orthogonal input waveforms that overlap in time and frequency.…

Orthogonal frequency division multiplexing (OFDM) signals with rectangularly windowed pulses exhibit low spectral confinement. Two approaches usually referred to as pulse-shaping and active interference cancellation (AIC) are classically…

Signal Processing · Electrical Eng. & Systems 2018-07-26 Luis Díez , José A. Cortés , Francisco J. Cañete , Eduardo Martos , Salvador Iranzo

Cascaded stimulated Brillouin scattering (SBS) is a complex nonlinear optical process that results in the generation of several optical waves that are frequency shifted by an acoustic resonance frequency. Four-wave mixing (FWM) between…

It is shown that inhomogeneous broadening of the spectral line of active impurities may sustain simultaneously parity (P) and time (T) symmetries of a medium, in a finite range of field frequencies, what is forbidden by the causality…

Optics · Physics 2018-11-20 D. M. Tsvetkov , V. A. Bushuev , V. V. Konotop , B. I. Mantsyzov

Nonlinear optics experiments measuring phase shifts induced in a weak probe pulse by a strong pump pulse must account for coherent effects that only occur when the pump and probe pulses are temporally overlapped. It is well known that a…

We demonstrate that Bragg scattering from a condensate can be sensitive to the spatial phase distribution of the initial state. This allows preferential scattering from a selected spatial region, and provides a robust signature for a vortex…

Soft Condensed Matter · Physics 2009-11-07 P. B. Blakie , R. J. Ballagh

We introduce a new optical component - a rotated chirped volume Bragg grating (r-CBG) - that spatially resolves the spectrum of a normally incident light beam in a compact footprint and without the need for subsequent free-space propagation…

Here, through a systematic methodology and the use of high performance computing, we calculate the optimum shape for a wave energy converter under the action of incident waves of (i) monochromatic unidirectional, (ii) monochromatic…

Fluid Dynamics · Physics 2018-05-23 Soheil Esmaeilzadeh , Mohammad-Reza Alam
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