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The fields of occultation and microlensing are linked historically. Early this century, occultation of the Sun by the Moon allowed the apparent positions of background stars projected near the limb of the Sun to be measured and compared…

Astrophysics · Physics 2007-05-23 Penny D. Sackett

We extend a modal theory of diffraction by a set of parallel fibers to deal with the case of a hard boundary: that is a structure made for instance of air-holes inside a dielectric matrix. Numerical examples are given concerning some…

Optics · Physics 2009-11-07 D. Felbacq , E. Centeno

This work concerns the design of perfectly conducting objects that are invisible to an incident transverse magnetic plane wave. The object in question is a finite planar waveguide with a finite periodic array of barriers. By optimizing this…

Computational Physics · Physics 2024-03-11 Johan Helsing , Shidong Jiang , Anders Karlsson

We introduce a novel algorithm, $\textit{COD}$ -- Compact Opacity Distribution, for shape reconstruction of a celestial body that has been observed to occult a star, using the photometric time-series observations of the occultation.…

Instrumentation and Methods for Astrophysics · Physics 2022-02-08 Gil Nachmani , Tsevi Mazeh , Nir Sochen

Several emerging microscopy imaging methods rely on complex interactions between the incident light and the sample. These include interferometry, spectroscopy, and nonlinear optics. Reconstructing a sample from the measured scattered field…

Optics · Physics 2024-04-12 Ruijiao Sun , Rohith Reddy , David Mayerich

By using the novel property of the rectangular superscatterer, we propose a design which can conceal an entrance from electromagnetic wave detection. Such a superscatterer is realized by coating a negative index material shell on a perfect…

Optics · Physics 2015-05-13 Xudong Luo , Tao Yang , Yongwei Gu , Hongru Ma

We provide a description of the far-field encountered in the diffraction problem resulting from the interaction of a monochromatic plane-wave and a right-angled no-contrast penetrable wedge. To achieve this, we employ a two-complex-variable…

Analysis of PDEs · Mathematics 2023-11-01 Valentin D. Kunz , Raphael C. Assier

In this paper, we present a novel approach to the estimation of strongly varying backgrounds in astronomical images by means of small objects removal and subsequent missing pixels interpolation. The method is based on the analysis of a…

Instrumentation and Methods for Astrophysics · Physics 2016-08-10 Adam Popowicz , Bogdan Smolka

A new recipe for concealing objects from detection is suggested. Different with traditional cloak which deflects light around the core of the cloak to make the object inside invisible, our cloak guides the light to penetrate the core of the…

Optics · Physics 2008-08-05 Yu Luo , Jingjing Zhang , Hongsheng Chen , Bae-Ian Wu , Jin Au Kong

The advantages of convergent beam electron diffraction for symmetry determination at the scale of a few nm are well known. In practice, the approach is often limited due to the restriction on the angular range of the electron beam imposed…

Materials Science · Physics 2013-07-09 Richard Beanland , Paul J. Thomas , David I. Woodward , Pamela A. Thomas , Rudolf A. Roemer

In the perturbative approach, substructures in the lens can be reduced to their effect on the two perturbative fields $f_1$ and $\frac{d f_0}{d\theta}$. A simple generic model of elliptical lens with a substructure situated near the…

Astrophysics · Physics 2009-11-13 C. Alard

Imaging for an occluded object is usually a difficult problem, in this letter, we introduce an imaging scheme based on computational ghost imaging, which can obtain the image of a target object behind an obstacle. According to our…

Optics · Physics 2019-05-22 Chao Gao , Xiaoqian Wang , Lidan Gou , Yuling Feng , Hongji Cai , Zhifeng Wang , Zhihai Yao

We suggest the numerical approach to detect eigenfrequencies of trapped modes in waveguides or guided waves in diffraction gratings. At the same time, the approach works perfectly for computation of systems with finitely many scattering…

Quantum Physics · Physics 2007-05-23 Valery E. Grikurov

Light field cameras and multi-camera arrays have emerged as promising solutions for accurately estimating depth by passively capturing light information. This is possible because the 3D information of a scene is embedded in the 4D light…

Image and Video Processing · Electrical Eng. & Systems 2025-05-15 Rui Lourenço , Lucas Thomaz , Eduardo A. B. Silva , Sergio M. M. Faria

We examine the transient scattered and transmitted fields generated when an incident electromagnetic wave impinges on a dielectric scatterer or a coated conductor embedded in an infinite space. By applying a boundary-field equation method,…

Analysis of PDEs · Mathematics 2024-12-19 George C. Hsiao , Tonatiuh Sánchez-Vizuet , Wolfgang L. Wendland

We propose a method to compute depth maps for every sub-aperture image in a light field in a view consistent way. Previous light field depth estimation methods typically estimate a depth map only for the central sub-aperture view, and…

Computer Vision and Pattern Recognition · Computer Science 2020-09-10 Numair Khan , Min H. Kim , James Tompkin

A brief overview of the current state of the problem of electromagnetic field singularities arising from the refraction and scattering of light by material objects is given. The discussion begins with caustics arising from ray tracing in…

Optics · Physics 2024-10-11 M. I. Tribelsky , B. S. Luk'yanchuk

One of the most important techniques for astrophysics with adaptive optics is the ability to do spectroscopy at diffraction limited scales. The extreme difficulty of positioning a faint target accurately on a very narrow slit can be avoided…

Astrophysics · Physics 2015-06-24 R. Davies , M. Kasper , N. Thatte , M. Tecza , L. E. Tacconi-Garman , S. Anders , T. Herbst

In this paper we consider the inverse electromagnetic scattering for a cavity surrounded by an inhomogeneous medium in three dimensions. The measurements are scattered wave fields measured on some surface inside the cavity, where such…

Analysis of PDEs · Mathematics 2020-12-10 Fang Zeng , Shixu Meng

Filled arrays of bolometers are currently being employed for use in astronomy from the far-infrared through millimeter parts of the electromagnetic spectrum. Because of the large range of wavelengths for which such detectors are applicable,…