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The inverse problem is studied in multi-body systems with nonlinear dynamics representing, e.g., phase-locked wave systems, standard multimode and random lasers. Using a general model for four-body interacting complex-valued variables we…

Disordered Systems and Neural Networks · Physics 2017-08-01 Alessia Marruzzo , Payal Tyagi , Fabrizio Antenucci , Andrea Pagnani , Luca Leuzzi

We consider the problem of imaging extended reflectors in terminating waveguides. We form the image by back-propagating the array response matrix projected on the waveguide's non-evanescent modes. The projection is adequately defined for…

Computational Physics · Physics 2017-11-30 Chrysoula Tsogka , Dimitrios A. Mitsoudis , Symeon Papadimitropoulos

We develop a model for the reflection and transmission of plane waves by an isotropic layer sandwiched between two uniaxial crystals of arbitrary orientation. In the laboratory frame, reflection and transmission coefficients corresponding…

Materials Science · Physics 2009-04-29 Erik S. Thomson , Larry A. Wilen , John S. Wettlaufer

Diffraction tomography is a widely used inverse scattering technique for quantitative imaging of weakly scattering media. In its conventional formulation, diffraction tomography assumes monochromatic plane wave illumination. This…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks , Otmar Scherzer

Multiple scattering of polarised electromagnetic waves in diffusive media is investigated by means of radiative transfer theory. The method becomes exact in several situations of interest, such as a thick-slab experiment (slab thickness L…

Condensed Matter · Physics 2009-10-28 E. Amic , J. M. Luck , Th. M. Nieuwenhuizen

The choice of a suitable regularization parameter is an important part of most regularization methods for inverse problems. In the absence of reliable estimates of the noise level, heuristic parameter choice rules can be used to accomplish…

Numerical Analysis · Mathematics 2022-05-23 Simon Hubmer , Ekaterina Sherina , Stefan Kindermann , Kemal Raik

An instantaneous time mirror (ITM) is an interesting approach to manipulate wave propagation from the time boundaries. In the time domain, the reversed wave is previously proven to be the temporal derivative of the original pattern. Here,…

Classical Physics · Physics 2020-08-19 Danming Peng , Yiyang Fan , Ruochen Liu , Xiasheng Guo , Sihui Wang

We present a novel numerical method to the time-harmonic inverse medium scattering problem of recovering the refractive index from near-field scattered data. The approach consists of two stages, one pruning step of detecting the scatterer…

Numerical Analysis · Mathematics 2015-06-05 Kazufumi Ito , Bangti Jin , Jun Zou

A method is presented to investigate diffraction of an electromagnetic plane wave by an infinitely thin infinitely conducting circular cylinder with longitudinal slots. It is based on the use of the combined boundary conditions method that…

Optics · Physics 2007-05-23 B. Guizal , D. Felbacq

In this article, we revisit iterative methods for solving the inverse problem of photoacoustic tomography in free space. Recently, there have been interesting developments on explicit formulations of the adjoint operator, demonstrating that…

Analysis of PDEs · Mathematics 2017-05-16 Markus Haltmeier , Linh V. Nguyen

In this paper we present a hybrid approach to numerically solve two-dimensional electromagnetic inverse scattering problems, whereby the unknown scatterer is hosted by a possibly inhomogeneous background. The approach is `hybrid' in that it…

Analysis of PDEs · Mathematics 2012-10-22 G. Giorgi , M. Brignone , R. Aramini , M. Piana

Wave reflection and refraction at a time interface follow different conservation laws compared to conventional scattering at a spatial interface. This study presents the experimental demonstration of refraction and reflection of flexural…

Decades of work on beam deformation on reflection, and especially on lateral shifts, have spread the idea that a reflected beam is larger than the incident beam. However, when the right conditions are met, a beam reflected by a multilayered…

We propose a multi-model formulation of full-waveform inversion that is similar to image decomposition into a "cartoon" and "texture" used in image processing. Inversion problem is formulated as unconstrained multi-norm optimization that…

Geophysics · Physics 2014-10-28 Musa Maharramov , Biondo Biondi

We consider wave scattering from a system of highly contrasting resonators with time-modulated material parameters. In this setting, the wave equation reduces to a system of coupled Helmholtz equations that models the scattering problem. We…

Mathematical Physics · Physics 2024-01-05 Habib Ammari , Jinghao Cao , Erik Orvehed Hiltunen , Liora Rueff

We present a new computation method for simulating reflection high-energy electron diffraction and the total-reflection high-energy positron diffraction experiments. The two experiments are used commonly for the structural analysis of…

Numerical Analysis · Mathematics 2023-06-02 Shuhei Kudo , Yusaku Yamamoto , Takeo Hoshi

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

We describe a method for recovering the irradiance underlying a collection of images corrupted by atmospheric turbulence. Since supervised data is often technically impossible to obtain, assumptions and biases have to be imposed to solve…

Computer Vision and Pattern Recognition · Computer Science 2024-06-25 Dong Lao , Congli Wang , Alex Wong , Stefano Soatto

We report on progress in algorithms for iterative phase retrieval. The theory of convex optimization is used to develop and to gain insight into counterparts for the nonconvex problem of phase retrieval. We propose a relaxation of averaged…

Optimization and Control · Mathematics 2009-11-10 D. Russell Luke

We propose in this paper a globally numerical method to solve a phaseless coefficient inverse problem: how to reconstruct the spatially distributed refractive index of scatterers from the intensity (modulus square) of the full complex…

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