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Related papers: Group delay in Bragg grating with linear chirp

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In this paper a theory of reflective X-ray multilayer structures with a graded (slowly varying) period based on the coupled waves method and quasi-classical asymptotic expansions is reported. A number of exact solutions of the coupled wave…

Optics · Physics 2022-04-26 R. M. Feshchenko

In this paper we employ the Renormalization Group (RG) method to study the long-time asymptotics of a class of nonlinear integral equations with a generalized heat kernel and with time-dependent coefficients. The nonlinearities are…

Mathematical Physics · Physics 2017-08-14 Gastão A. Braga , Jussara M. Moreira , Camila F. Souza

Time delay signature (TDS) of a semiconductor laser subject to dispersive optical feedback from a chirped fiber Bragg grating (CFBG) is investigated experimentally and numerically. Different from mirror, CFBG provides additional…

We introduce a new iterative method for computing solutions of elliptic equations with random rapidly oscillating coefficients. Similarly to a multigrid method, each step of the iteration involves different computations meant to address…

Numerical Analysis · Mathematics 2020-03-31 S. Armstrong , A. Hannukainen , T. Kuusi , J. -C. Mourrat

Higher precision efficient computation of period 1 relaxation oscillations of strongly nonlinear and singularly perturbed Rayleigh equations with external periodic forcing is presented. The computations are performed in the context of…

Chaotic Dynamics · Physics 2021-09-23 Aniruddha Palit , Dhurjati Prasad Datta , Santanu Raut

Simple models of clarinet instruments based on iterated maps have been used in the past to successfully estimate the threshold of oscillation of this instrument as a function of a constant blowing pressure. However, when the blowing…

Classical Physics · Physics 2014-07-16 Baptiste Bergeot , André Almeida , Christophe Vergez , Bruno Gazengel

Gamma-ray bursts (GRBs) are fascinating extragalactic objects. They represent a fantastic opportunity to investigate unique properties not exhibited in other sources. Multi-wavelength afterglow observations from some short- and…

We propose dynamical Bragg mirrors as a means to compress intense short optical pulses. We show that strong-field photoexcitation of carriers changes the refractive index of the layers and leads to motion of the resonance-defined boundary…

Optics · Physics 2025-01-16 Zukhriddin Ruziev , Kazuhiro Yabana , Anton Husakou

For the oblique helicoidal structure of the chiral twist-bend nematic-forming mixture of CB7CB/CB6OCB/5CB doped by light-sensitive chiral compound based on azo-fragment, two consequent states of Bragg reflection of the light in the visible…

Soft Condensed Matter · Physics 2024-04-08 H. Bogatyryova , V. Chornous , L. Lisetski , I. Gvozdovskyy

Many problems in machine learning write as the minimization of a sum of individual loss functions over the training examples. These functions are usually differentiable but, in some cases, their gradients are not Lipschitz continuous, which…

Optimization and Control · Mathematics 2024-04-29 S. Chraibi , F. Iutzeler , J. Malick , A. Rogozin

It is shown that the transmission and reflection group delay times in an asymmetric single quantum barrier are greatly enhanced by the transmission resonance when the energy of incident particles is larger than the height of the barrier.…

Quantum Physics · Physics 2007-05-23 Chun-Fang Li

We provide a comprehensive study of atomic Raman and Bragg diffraction when coupling to a pair of counterpropagating light gratings (double diffraction) or to a single one (single diffraction) and discuss the transition from one case to the…

We present two sets of theoretical results on the grouped lasso with overlap of Jacob, Obozinski and Vert (2009) in the linear regression setting. This method allows for joint selection of predictors in sparse regression, allowing for…

Machine Learning · Statistics 2011-11-11 Daniel Percival

We derive from first principles the expression for the angular/wavelength distribution of the intensity diffracted by a blazed reflective grating, according to a scalar theory of diffraction. We considered the most common case of a groove…

Optics · Physics 2015-06-22 R. Casini , P. G. Nelson

We present a simple and direct method for measuring laser chirp rate, i.e., group delay dispersion (GDD) of ultrashort laser pulses at power levels compatible with single-quantum-emitter excitation. Traditional pulse characterization…

We study the transmission and group delay time for fermions in graphene under a proximity exchange field scattered by double barriers. Solving the Dirac equation over five regions, we calculate transmission and reflection coefficients using…

Mesoscale and Nanoscale Physics · Physics 2025-03-06 Ahmed Jellal , Rachid El Aitouni , Pablo Díaz , David Laroze

We introduce stable reflection length in Coxeter groups, as a way to study the asymptotic behaviour of reflection length. This creates connections to other well-studied stable length functions in groups, namely stable commutator length and…

Group Theory · Mathematics 2025-04-02 Francesco Fournier-Facio , Marco Lotz , Timothée Marquis

We derive the closed form Cramer-Rao bound (CRB) expressions for joint estimation of time delay and Doppler shift with unknown signals with possibly known structure. The results are especially useful for passive radar where direct path and…

Signal Processing · Electrical Eng. & Systems 2018-05-07 Yicheng Chen , Rick S. Blum

The effect of anti-mirror reflection from a bounded plane optical waveguide used earlier for observation of slow light in a Bragg waveguide is considered. A theory of the effect is proposed that allowed us to interpret the observed spectral…

Mesoscale and Nanoscale Physics · Physics 2014-03-07 P. Yu. Shapochkin , Yu. V. Kapitonov , G. G. Kozlov

The detection of delayed X-ray, optical and radio emission, "afterglow", associated with $\gamma$-ray bursts (GRBs) is consistent with fireball models, where the emission are produced by relativistic expanding blast wave, driven by…

Astrophysics · Physics 2009-10-30 D. M. Wei , T. Lu