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In this paper we couple Synchrotron Radiation (SR) theory with a branch of physical optics, namely laser beam optics. We show that the theory of laser beams is successful in characterizing radiation fields associated with any SR source.…

Estimating the angular separation between two incoherent thermal sources is a challenging task for direct imaging, especially when it is smaller than or comparable to the Rayleigh length. In addition, the task of discriminating whether…

Quantum Physics · Physics 2025-06-23 Ugo Zanforlin , Cosmo Lupo , Peter W. R. Connolly , Pieter Kok , Gerald S. Buller , Zixin Huang

We have developed a new three-dimensional algorithm, based on the standard P$^3$M method, for computing deflections due to weak gravitational lensing. We compare the results of this method with those of the two-dimensional planar approach,…

Astrophysics · Physics 2009-10-31 H. M. P. Couchman , Andrew J. Barber , Peter A. Thomas

We study an inverse problem for the wave equation where localized wave sources in random scattering media are to be determined from time resolved measurements of the waves at an array of receivers. The sources are far from the array, so the…

Mathematical Physics · Physics 2016-07-18 Liliana Borcea , Ilker Kocyigit

This work introduces a novel reinterpretation of structured illumination (SI) microscopy for coherent imaging that allows three-dimensional imaging of complex refractive index (RI). To do so, we show that coherent SI is mathematically…

Optics · Physics 2017-05-11 Shwetadwip Chowdhury , Will J. Eldridge , Adam Wax , Joseph A. Izatt

Diffusion models have established new state of the art in a multitude of computer vision tasks, including image restoration. Diffusion-based inverse problem solvers generate reconstructions of exceptional visual quality from heavily…

Image and Video Processing · Electrical Eng. & Systems 2024-08-21 Zalan Fabian , Berk Tinaz , Mahdi Soltanolkotabi

A point spread function of hexagonally segmented telescopes is derived by a new symmetrical formulation. By introducing three variables on a pupil plane, the Fourier transform of pupil functions is derived by a three-dimensional Fourier…

Instrumentation and Methods for Astrophysics · Physics 2018-11-28 Satoshi Itoh , Taro Matsuo , Shibai Hiroshi , Takahiro Sumi

We introduce a novel reflection-mode diffraction tomography technique that enables simultaneous recovery of forward and backward scattering information for high-resolution 3D refractive index reconstruction. Our technique works by imaging a…

Optics · Physics 2025-02-12 Tongyu Li , Jiabei Zhu , Yi Shen , Lei Tian

For linear and fully non-linear diffusion equations of Bellman-Isaacs type, we introduce a class of approximation schemes based on differencing and interpolation. As opposed to classical numerical methods, these schemes work for general…

Numerical Analysis · Mathematics 2014-05-26 Kristian Debrabant , Espen R. Jakobsen

We present here a real-time analysis of diffraction images acquired at high frame-rate (925 Hz) and its application to macromolecular serial crystallography. The software uses a new signal separation algorithm, able to distinguish the…

We propose a semi-analytical modeling of smoothed laser beams deviation induced by plasma flows. Based on a Gaussian description of speckles, the model includes spatial, temporal and polarization smoothing techniques,through fits issued…

Plasma Physics · Physics 2022-09-05 C. Ruyer , P. Loiseau , G. Riazuelo , R. Riquier , A. Debayle , P. E. Masson-Laborde

An inverse scattering problem for SAR data in application to through-the-wall imaging is addressed. In contrast with the conventional algorithms of SAR imaging, that work with the linearized mathematical model based on the Born…

Numerical Analysis · Mathematics 2021-09-08 Michael V. Klibanov , Alexey V. Smirnov , Vo Anh Khoa , Anders J. Sullivan , Lam H. Nguyen

This paper concerns the inverse source scattering problems of recovering random sources for acoustic and elastic waves. The underlying sources are assumed to be random functions driven by an additive white noise. The inversion process aims…

Numerical Analysis · Mathematics 2024-12-10 Yan Chang , Yukun Guo , Zhipeng Yang , Yue Zhao

We apply the stationary phase method developed in (Assier, Shanin \& Korolkov, QJMAM, 76(1), 2022) to the problem of wave diffraction by a quarter-plane. The wave field is written as a double Fourier transform of an unknown spectral…

Analysis of PDEs · Mathematics 2023-10-30 Raphael C. Assier , Andrey V. Shanin , Andrey I. Korolkov

A set of semi-analytical techniques based on Fourier analysis is used to solve wave scattering problems in variously shaped waveguides with varying normal admittance boundary conditions. Key components are newly developed conformal mapping…

Mathematical Physics · Physics 2015-06-02 Anders Andersson , Borje Nilsson , Thomas Biro

Various methods have been introduced to measure the orbital angular momentum (OAM) of light, from fork holograms to Dove prism interferometers, from tilted lenses to triangular apertures - each with their own benefits and limitations. Here…

Recent experimental work has demonstrated the potential to combine the merits of diffractive and on-chip photonic information processing devices in a single chip by making use of planar (or slab) waveguides. Researchers have adapted key…

Optics · Physics 2023-05-26 Benjamin Wetherfield , Timothy D. Wilkinson

Recent advances in diffusion models have enabled the creation of deceptively real images, posing significant security risks when misused. In this study, we empirically show that different timesteps of DDIM inversion reveal varying subtle…

Computer Vision and Pattern Recognition · Computer Science 2025-07-29 Yixin Wu , Feiran Zhang , Tianyuan Shi , Ruicheng Yin , Zhenghua Wang , Zhenliang Gan , Xiaohua Wang , Changze Lv , Xiaoqing Zheng , Xuanjing Huang

In this paper, we show by experiment that by covering a thin flat nonlinear lens on the sources, the sub-diffraction-limit observation can be achieved by measuring either the near-field distribution or the far-field radiation of the sources…

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by…