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We describe several extensions to TIM, a raytracing program for ray-optics research. These include relativistic raytracing; simulation of the external appearance of Eaton lenses, Luneburg lenses and generalized focusing gradient-index…

Physics Education · Physics 2015-06-16 Stephen Oxburgh , Tomas Tyc , Johannes Courtial

If an extended source, such as a galaxy, is gravitationally lensed by a massive object in the foreground, the lensing distorts the observed image. It is straightforward to simulate what the observed image would be for a particular lens and…

Astrophysics · Physics 2009-11-13 Brendon J. Brewer , Geraint F. Lewis

Modeling strong gravitational lenses in order to quantify the distortions in the images of background sources and to reconstruct the mass density in the foreground lenses has been a difficult computational challenge. As the quality of…

Instrumentation and Methods for Astrophysics · Physics 2023-07-05 Alexandre Adam , Laurence Perreault-Levasseur , Yashar Hezaveh , Max Welling

Gravitational lensing is brightening of background objects due to deflection of light by foreground sources. Rich clusters of galaxies are very effective lenses because they are centrally concentrated. Such natural Gravitational Telescopes…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Margarita Safonova

In the coming years, strong gravitational lens discoveries are expected to increase in frequency by two orders of magnitude. Lens-modelling techniques are being developed to prepare for the coming massive influx of new lens data, and blind…

Astrophysics of Galaxies · Physics 2020-06-18 Philipp Denzel , Sampath Mukherjee , Jonathan P. Coles , Prasenjit Saha

In this work, an analytic expression is derived for the optical field generated by an off-axis Gaussian beam diffracted by a Discrete Vortex-Producing Lens. With this system, a multifocal arrangement of asymmetric optical vortices is…

Materials with extreme photonic properties such as maximum diffuse reflectance, high albedo, or tunable band gaps are essential in many current and future photonic devices and coatings. While photonic crystals, periodic anisotropic…

Stacked layers of metal meshes embedded in a dielectric substrate are routinely used for providing spectral selection at THz frequencies. Recent work has shown that particular geometries allow the refractive index to be tuned to produce…

Optics · Physics 2012-12-14 Giorgio Savini , Peter A. R. Ade , Jin Zhang

The study of light lensed by cosmic matter has yielded much information about astrophysical questions. Observations are explained using geometrical optics following a ray-based description of light. After deflection the lensed light…

Instrumentation and Methods for Astrophysics · Physics 2023-06-22 Valeria Rodriguez-Fajardo , Thao P. Nguyen , Kiyan S. Hocek , Jacob M. Freedman , Enrique J. Galvez

Metasurfaces are an emerging technology that may supplant many of the conventional optics found in imaging devices, displays, and precision scientific instruments. Here, we develop a method for designing optical systems composed of multiple…

Optics · Physics 2019-10-23 Adam S. Backer

An analysis of electron transport in graphene is presented in the presence of various arrangement of delta-function like magnetic barriers. The motion through one such barrier gives an unusual non specular refraction leading to asymmetric…

Mesoscale and Nanoscale Physics · Physics 2009-07-09 Sankalpa Ghosh , Manish Sharma

Microlensing imprints by typical stellar mass lenses on gravitational waves are challenging to identify in the LIGO and Virgo frequency band because such effects are weak. However, stellar mass lenses are generally embedded in lens galaxies…

High Energy Astrophysical Phenomena · Physics 2023-12-01 Eungwang Seo , Otto A. Hannuksela , Tjonnie G. F. Li

We quantitatively investigate multiple algorithms for microlens array grid estimation for microlens array-based light field cameras. Explicitly taking into account natural and mechanical vignetting effects, we propose a new method for…

Image and Video Processing · Electrical Eng. & Systems 2020-10-19 Maximilian Schambach , Fernando Puente León

The strong galaxy-galaxy lensing produces highly magnified and distorted images of background galaxies in the form of arcs and Einstein rings. Statistically, these effects are quantified, for example, in the number counts of highly luminous…

Astrophysics of Galaxies · Physics 2019-03-08 Vanessa P. de Freitas , Martin Makler , Habib S. Dúmet-Montoya

The visual analysis of retina and of its vascular characteristics is important in the diagnosis and monitoring of diseases of visual perception. In the related medical diagnoses, the digital processing of the fundus images is used to obtain…

Computer Vision and Pattern Recognition · Computer Science 2015-08-06 Amelia Carolina Sparavigna

Diffractive lenses fabricated by lithographic methods are one of the most popular image forming optics in the x-ray regime. Most commonly, binary diffractive optics, such as Fresnel zone plates are used due to their ability to focus at high…

Optics · Physics 2019-06-10 Stefano Marchesini , Anne Sakdinawat

Distinguishing visually similar objects like forged/authentic bills and healthy/unhealthy plants is beyond the capabilities of even the most sophisticated classifiers. We propose the use of multiplexed illumination to extend the range of…

Computer Vision and Pattern Recognition · Computer Science 2021-02-24 Taihua Wang , Donald G. Dansereau

A series of thin layers of alternating refractive index is known to make a good optical mirror over certain bands of frequency. Such a device - often termed the Bragg reflector - is usually introduced to students within the first years of…

Optics · Physics 2015-06-12 S. A. R. Horsley , J. -H. Wu , M. Artoni , G. C. La Rocca

Twisting and stacking two copies of a 2D crystal can produce a long-wavelength periodic interference pattern known as a moir\'e pattern. Performing the same procedure with an aperiodic structure instead generates a single moir\'e spot at…

Disordered Systems and Neural Networks · Physics 2025-11-04 Aaron Dunbrack

Within the last decade microscopic multiphase flows have gained broad interest. An exact understanding of the underlying hydrodynamic interrelations is the key for successful reactor layout and reaction control. To examine the local…

Fluid Dynamics · Physics 2020-02-14 Thorben Helmers , Philip Kemper , Ulrich Mießner , Jorg Thöming