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Related papers: Photon Trajectory in the Human Cornea

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Biomedical optical imaging has a possibility of a comprehensive diagnosis of thyroid cancer in conjunction with ultrasound imaging. For improvement of the optical imaging, this study develops a higher order scheme for solving the…

Medical Physics · Physics 2016-03-15 Hiroyuki Fujii , Shinpei Okawa , Ken Nadamoto , Eiji Okada , Yukio Yamada , Yoko Hoshi , Masao Watanabe

This work seeks to present an investigation about the trajectories followed by rays of light passing through refractive index gradients that was entirely carried by high school students. Such trajectories are curved, therefore contradicting…

Optics · Physics 2025-10-07 Oliver Polachini , Fabricio Marques

Optical sections of the cornea are obtained by illumination with a collimated beam expanded in a fan shape by a small rotary cylindrical lens. The light diffused from the cornea is observed by two cameras and processed in order to yield the…

Medical Physics · Physics 2007-05-23 Jose B. Almeida , Sandra Franco

The accurate visual tracking of a moving object is a human fundamental skill that allows to reduce the relative slip and instability of the object's image on the retina, thus granting a stable, high-quality vision. In order to optimize…

Neurons and Cognition · Quantitative Biology 2016-11-24 Anna Montagnini , Laurent Perrinet , Guillaume S Masson

In this work, we present the design of cycloidal waveguides from a gradient refractive index (GRIN) medium in analogy to the fastest descending problem in classical mechanics. Light rays propagate along cycloids in this medium, of which the…

Optics · Physics 2024-04-04 Xiong Hui , Zijun He , Yangjie Liu

A new transport regime of photon in two-dimensional photonic crystal near the Dirac point has been demonstrated by exact numerical simulation. In this regime, the conductance of photon is inversely proportional to the thickness of sample,…

Materials Science · Physics 2009-11-13 Xiangdong Zhang

We explore in some detail the scenario proposed to explain the observed knee of the cosmic ray (CR) spectrum as due to the effects of photodisintegration of the CR nuclei by interactions with optical and soft UV photons in the source…

Astrophysics · Physics 2009-10-31 Julian Candia , Luis N. Epele , Esteban Roulet

Graded index (GRIN) lenses are commonly used for compact imaging systems. It is not widely appreciated that the ion-exchange process that creates the rotationally symmetric GRIN lens index profile also causes a symmetric birefringence…

In this paper we describe an adaptive and multi-scale algorithm for the parsimonious fit of the corneal surface data that allows to adapt the number of functions used in the reconstruction to the conditions of each cornea. The method…

Many works in elasticity have exploited the concept of gradient index (GRIN) lenses, borrowed from optics, for wave focusing and control. These effects are particularly attractive for cloaking, absorption or energy harvesting applications.…

Applied Physics · Physics 2024-09-04 P. H. Beoletto , F. Nistri , A. S. Gliozzi , N. M. Pugno , F. Bosia

The evaluation and monitoring of cells health in the human retina is crucial and follow time course of retinal diseases, detect lesions before irreversible visual loss and to evaluate treatment effects. Towards this goal, a major challenge…

We investigate the electron transport in smooth graphene pn junctions, generated by gradually varying electrostatic potentials. The numerically calculated coherent current flow patterns can be understood largely in terms of semi-classical…

Mesoscale and Nanoscale Physics · Physics 2021-01-13 Emmanuel Paredes-Rocha , Yonatan Betancur-Ocampo , Nikodem Szpak , Thomas Stegmann

Retinal image-based eye tracking is widely used in ophthalmic imaging and vision science, and is a promising path to deliver higher gaze accuracy than the pupil- and cornea-based approaches commonly used in modern AR/VR devices.…

Computer Vision and Pattern Recognition · Computer Science 2026-05-12 Bo Wen , Dillon Lohr , Yatong An , Pushkar Anand , Alexander Fix , Ruobing Qian , Catherine A. Fromm , Yimin Ding , Truong Nguyen , Mohamed El-Haddad , Francesco La Rocca

Gradient index (GRIN) fibers are used to improve the design of many fiber optic devices. However, the properties of the GRIN fiber must be determined to optimally engineer a device which incorporates GRIN fiber components. The index of…

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

We put forward a first-principle NonEquilibrium Green's Function (NEGF) approach to calculate the transient photoabsorption spectrum of optically thin samples. The method can deal with pump fields of arbitrary strength, frequency and…

Atomic Physics · Physics 2015-09-30 E. Perfetto , A. -M. Uimonen , R. van Leeuwen , G. Stefanucci

According to Albert Einstein, gravitation is analogous to an optical medium. Building on this idea, various definitions of the gradient-index (GRIN) medium representing curved spacetime have been proposed; often, these approaches demand…

General Relativity and Quantum Cosmology · Physics 2025-06-13 J. E. Gómez-Correa , E. Espíndola-Ramos , O. López-Cruz , S. Chávez-Cerda

The human retina contains a complex arrangement of photoreceptors that convert light into visual information. Conventional image sensors mimic the trichromacy of the retina using periodic filter mosaics responsive to three primary colors.…

Being able to image the human retina in high resolution opens a new era in many important fields, such as pharmacological research for retinal diseases, researches in human cognition, nervous system, metabolism and blood stream, to name a…

Optics · Physics 2016-05-25 Guillaume Molodij , Erez N. Ribak , Marie Glanc , Guillaume Chenegros

Vital to primary visual processing, retinal circuitry shows many similar structures across a very broad array of species, both vertebrate and non-vertebrate, especially functional components such as lateral inhibition. This surprisingly…

Neural and Evolutionary Computing · Computer Science 2021-02-23 Ziyi Gong , Paul Munro
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