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The principles behind the sharp, singular structures in a crumpled sheet are well understood. Here we discuss more general ways of exploiting such sharp structures to control the shape of a sheet by deforming or forcing it elsewhere. Often,…

Soft Condensed Matter · Physics 2025-03-24 Thomas A. Witten , Anna Movsheva

Optical singularities play a major role in modern optics and are frequently deployed in structured light, super-resolution microscopy, and holography. While phase singularities are uniquely defined as locations of undefined phase,…

We analyze spectral properties of a quantum graph in the form of a ring chain with a $\delta$ coupling in the vertices exposed to a homogeneous magnetic field perpendicular to the graph plane. We find the band spectrum in the case when the…

Mathematical Physics · Physics 2019-12-10 Pavel Exner , Stepan S. Manko

Optical speckle patterns have been widely used for illumination in computational imaging, optical sectioning microscopy, and super-resolution imaging. However, commonly used speckles satisfy Rayleigh statistics, which are not ideal for…

Self-organization is the spontaneous formation of spatial, temporal, or spatiotemporal patterns in complex systems far from equilibrium. During such self-organization, energy distributed in a broadband of frequencies gets condensed into a…

Adaptation and Self-Organizing Systems · Physics 2020-12-08 Induja Pavithran , Vishnu R. Unni , Alan John Varghese , D. Premraj , R. I. Sujith , C. Vijayan , Abhishek Saha , Norbert Marwan , Jürgen Kurths

Topological singularities are ubiquitous in many areas of physics. Polarization singularities are locations at which an aspect of the polarization ellipse of light becomes undetermined or degenerate. At C points the orientation of the…

Optics · Physics 2018-10-24 L. De Angelis , F. Alpeggiani , L. Kuipers

In this article, we study the emergence of polarization singularities in the scattered fields of optical resonators excited by linearly polarized plane waves. First, we prove analytically that combinations of isotropic electric and magnetic…

Mesoscale and Nanoscale Physics · Physics 2017-07-28 Aitzol Garcia-Etxarri

Laser speckle is generated by the multiple interference of light through a disordered medium. Here we study the premise that the speckle pattern retains information about the polarisation state of the incident field. We analytically verify…

Optics · Physics 2020-05-13 Morgan Facchin , Graham D. Bruce , Kishan Dholakia

Speckle interferometry is an established optical metrology tool for the characterization of rough objects. The raw phase, however, is impaired by the presence of phase singularities, making the unwrapping procedure ambiguous. In a Michelson…

Instrumentation and Detectors · Physics 2016-11-11 Klaus Mantel , Vanusch Nercissian

The multiple scattering of coherent light is a problem of both fundamental and applied importance. In optics, phase conjugation allows spatial focussing and imaging through a multiply scattering medium; however, temporal control is…

Visual object recognition under situations in which the direct line-of-sight is blocked, such as when it is occluded around the corner, is of practical importance in a wide range of applications. With coherent illumination, the light…

Computer Vision and Pattern Recognition · Computer Science 2019-04-17 Xin Lei , Liangyu He , Yixuan Tan , Ken Xingze Wang , Xinggang Wang , Yihan Du , Shanhui Fan , Zongfu Yu

It is well known that when a laser is reflected from a rough surface or transmitted through a diffusive medium, a speckle pattern will be formed at a given observation plane. Speckle is commonly produced by laser beams with a homogeneous…

Optics · Physics 2019-06-18 Xiao-Bo Hu , Meng-Xuan Dong , Zhi-Han Zhu , Wei Gao , Carmelo Rosales-Guzman

We study the size and regularity properties of level sets of continuous functions with bounded upper-scaled and lower-scaled oscillation.

Classical Analysis and ODEs · Mathematics 2021-07-14 Iqra Altaf , Marianna Csornyei , Bobby Wilson

Coherent wave propagation in random media results in a characteristic speckle pattern, with spatial intensity correlations with short-range and long-range behavior. Here, we show how the speckle correlation function can be obtained from a…

Mesoscale and Nanoscale Physics · Physics 2014-08-06 Maxim Breitkreiz , Piet W. Brouwer

The interaction of optical vortices (or phase singularities, screw dislocations) with ordinary matter is treated with simple approach. Using total internal reflection phenomenon and superposition of four plane waves incident on a material…

Optics · Physics 2015-05-20 P. A. Brandão , C. J. S. Julião

Weird galaxies are outliers that have either unknown or very uncommon features making them different from the normal sample. These galaxies are very interesting as they may provide new insights into current theories, or can be used to form…

Astrophysics of Galaxies · Physics 2020-07-20 Job Formsma , Teymoor Saifollahi

Photon coincidence spectroscopy is a promising technique for probing the nonlinear regime of cavity quantum electrodynamics in the optical domain, however its accuracy is mitigated by two factors: higher-order photon correlations, which…

Quantum Physics · Physics 2009-09-25 L. Horvath , B. C. Sanders

Speckle patterns generated in a disordered medium carry a lot of information despite the apparent complete randomness in the intensity pattern. When the medium possesses $\chi^{(2)}$ nonlinearity, the speckle is sensitive to the phase of…

(abridged) Imaging observations are generally affected by a fluctuating background of speckles, a particular problem when detecting faint stellar companions at small angular separations. Knowing the distribution of the speckle intensities…

Astrophysics · Physics 2009-11-13 Michael P. Fitzgerald , James R. Graham

Chromaticity effects introduced by the finite source size in microlensing events by presumed natural wormholes are studied. It is shown that these effects provide a specific signature that allow to discriminate between ordinary and negative…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Ernesto Eiroa , Gustavo E. Romero , Diego F. Torres