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This paper studies the theory and applications of the diffraction of electromagnetic waves by space-time periodic (STP) diffraction gratings. We show that, in contrast with conventional spatially periodic grating, a STP diffraction grating…

Applied Physics · Physics 2019-08-21 Sajjad Taravati , George V. Eleftheriades

We report that metamaterial-inspired one-dimensional gratings (or metagratings) can be used to control nonpropagating diffraction orders as well as propagating ones. By accurate engineering of the near field, it becomes possible to satisfy…

Applied Physics · Physics 2019-03-06 Vladislav Popov , Fabrice Boust , Shah Nawaz Burokur

Light matter interactions can be substantially altered in the presence of time varying media. We study the interaction between a harmonic electric dipole and a plasmonic time crystal slab. Temporal modulation of the plasma frequency enables…

Remote focusing of light in a graded-index medium via mode interference is demonstrated using exact analytical solutions of the wave equation. Strong focusing of light occurs at extremely long distances and it revivals periodically with…

Optics · Physics 2015-12-09 Nikolai I. Petrov

A rigorous mathematical model and an efficient computational method are proposed to solving the inverse elastic surface scattering problem which arises from the near-field imaging of periodic structures. We demonstrate how an enhanced…

Analysis of PDEs · Mathematics 2017-12-08 Huaian Diao , Peijun Li , Xiaokai Yuan

The image subtraction method is a powerful tool to analyze the light variations in crowded fields. This method is able to achieve a nearly optimal differential photometry, even in very dense regions. However, image subtraction is not…

Astrophysics · Physics 2007-05-23 C. Alard

Focusing waves inside inhomogeneous media is a fundamental problem for imaging. Spatial variations of wave velocity can strongly distort propagating wavefronts and degrade image quality. Adaptive focusing can compensate for such aberration,…

Image and Video Processing · Electrical Eng. & Systems 2020-06-15 William Lambert , Laura A. Cobus , Thomas Frappart , Mathias Fink , Alexandre Aubry

This paper presents a novel approach to reconstruct complete 3D deformable models over time by a single depth camera. These are the steps employed for deforming objects from single depth camera. The partial surfaces reconstructed from…

Computer Vision and Pattern Recognition · Computer Science 2017-08-31 Vamshhi Pavan Kumar Varma Vegeshna

Talbot length, the distance between two consecutive self-image planes along the propagation axis for a periodic diffraction object (grating) illuminated by a plane wave, depends on the period of the object and the wavelength of…

Optics · Physics 2024-08-21 Saumya J. Sarkar , M. Ebrahim-Zadeh , G. K. Samanta

An imaging system is proposed for matter-wave functions that is based on producing a quadratic phase modulation on the wavefunction of a charged particle, analogous to that produced by a space or time lens. The modulation is produced by…

Quantum Physics · Physics 2020-10-28 Brian H. Kolner

A topology optimization method is presented and applied to a blazed diffraction grating in reflection under conical incidence. This type of gratings is meant to disperse the incident light on one particular diffraction order and this…

Computational Physics · Physics 2024-11-06 Simon Ans , Frédéric Zamkotsian , Guillaume Demésy

This paper presents an adaptive and intelligent sparse model for digital image sampling and recovery. In the proposed sampler, we adaptively determine the number of required samples for retrieving image based on space-frequency-gradient…

Computer Vision and Pattern Recognition · Computer Science 2017-11-27 Ali Taimori , Farokh Marvasti

In this paper, a spatially dispersive finite-difference time-domain (FDTD) method to model wire media is developed and validated. Sub-wavelength imaging properties of the finite wire medium slabs are examined. It is demonstrated that the…

Optics · Physics 2009-11-11 Yan Zhao , Pavel A. Belov , Yang Hao

Thermo- and photo- acoustic tomography require reconstructing initial acoustic pressure in a body from time series of pressure measured on a surface surrounding the body. For the classical case of free space wave propagation, various…

Analysis of PDEs · Mathematics 2015-06-23 B. Holman , L. Kunyansky

To overcome the resolution limit of conventional optics, near field imaging techniques using a negative index flat lens (NIFL) have been previously developed that amplify the evanescent components of the incident field. Here, a technique is…

Optics · Physics 2016-12-23 Wyatt Adams , Durdu Ö. Güney

We have developed an application of a one-dimensional micro-strip detector for capturing x-ray diffraction data in pulsed magnetic fields. This detector consists of a large array of 50 \mu m-wide Si strips with a full-frame read out at 20…

Instrumentation and Detectors · Physics 2015-05-30 Zahirul Islam , Jacob P. C. Ruff , Kate A. Ross , Hiroyuki Nojiri , Bruce D. Gaulin

We introduce an absorption imaging technique for ultracold gases that suppresses interference fringes and coherence-induced artifacts by reducing the transverse spatial coherence of the imaging light. The method preserves the narrow…

Quantum Gases · Physics 2026-02-16 Julia Fekete , Poppy Joshi , Peter Krüger , Fedja Oručević

Lensless imaging is an important and challenging problem. One notable solution to lensless imaging is a single pixel camera which benefits from ideas central to compressive sampling. However, traditional single pixel cameras require many…

Computer Vision and Pattern Recognition · Computer Science 2017-03-31 Guy Satat , Matthew Tancik , Ramesh Raskar

We propose a multi-field-coupled atomic model that exhibits controllable $symmetric$ and $asymmetric$ evolution of significantly enhanced diffraction peaks in an opto-atomic grating at far-field regime. Such results are obtained by the…

Real-time magnetic resonance imaging (MRI) methods generally shorten the measuring time by acquiring less data than needed according to the sampling theorem. In order to obtain a proper image from such undersampled data, the reconstruction…

Numerical Analysis · Mathematics 2013-12-05 Housen Li , Markus Haltmeier , Shuo Zhang , Jens Frahm , Axel Munk
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