We present in this work a numerical model for characterizing the scattering properties of the human lens. After analyzing the scattering properties of two main scattering particles actually described in the literature through Finite Element Method simulations, we have modified a Monte Carlo bulk scattering algorithm for computing ray scattering in non-sequential ray tracing. We have implemented this ray scattering algorithm in a layered model of the human lens in order to calculate the scattering properties of the whole lens. We have tested our algorithm by simulating the classic experiment carried out by Van der Berg et al for measuring in vitro the angular distribution of forward scattered light by the human lens. The results show the ability of our model to simulate accurately the scattering properties of the human lens.
In this work, a reflective beam-splitter based on a metallic Ronchi diffraction grating normally illuminated is designed and analysed. This kind of beam-splitter could have potential applications in photonics and optical technologies in which robustness is necessary since it may be manufactured over malleable metallic substrates. The main idea under the design is as simple as obligating the zero-th diffraction order to be null. Firstly, scalar approach is performed, showing an approximation to the parameters of the grating necessary to achieve beam-splitting. After that, a more rigorous approach such as Rigorous Coupled Waves Analysis (TE and TM polarization) is used to evaluate the proposed diffraction gratings as reflective beam-splitters. Beam-splitting is demonstrated for TE and TM polarization with slightly different dimensional parameters of the diffraction grating. Besides, we show how physical height of the grating grooves that allows cancelling zero-th diffraction order for a certain illumination wavelength depends on the metals used to manufacture the grating and its period. The dependence of the grooves height on the period is exponentially decreasing. To complete the an
Spatial coherence of light sources is usually obtained by using the classical Youngs interferometer. Despite the original experiment has been improved in successive works, some drawbacks still remain. In addition, several pairs of points must be used to characterize the totally the 2D complex-coherence degree of the source. In this work, an alternative based on a modified Mach-Zehnder interferometer which includes a pair of lenses is presented. With this modified Mach-Zehnder interferometer, we are able to measure the spatial coherence length between any two points of the laser beam section simultaneously. The set-up does not have any movable part, which makes it robust and portable. To test it, the two-dimensional spatial coherence of a high-speed laser with two cavities has been measured for different pulse energy values. We observe from the experimental measurements that the complex degree of coherence changes with the selected output energy. Both laser cavities seem to have similar complex coherence degree for maximum energy although it is not symmetrical. Thus, this analysis will allow us to determine the best configuration of the double cavity laser for interferometric applic
Understanding the untreated tumor growth kinetics and its intrinsic findings is interesting and intriguing. The aim of this study is to propose an approximate analytical expression that allows to simulate changes in surface charge density changes at cancer-surrounding healthy tissue interface during the untreated solid tumor growth. For this, the Gompertz and Poisson equations are used. Simulations reveal that the unperturbed solid tumor growth is closely related to changes in the surface charge density over time between the tumor and the surrounding healthy tissue. Furthermore, the unperturbed solid tumor growth is governed by temporal changes in this surface charge density. It is concluded that graphic strategies corroborate the correspondence between the electrical and physiological parameters in the untreated cancer, which may have an essential role in its growth, progression, metastasis and protection against immune system attack and anti-cancer therapies. In addition, the knowledge of surface charge density changes at cancer-surrounding healthy tissue interface may be relevant when redesigning the molecules in chemotherapy and immunotherapy taking into account their polaritie
A new sunlight-powered material can convert visible light into higher-energy UV light, overcoming a challenge that has frustrated scientists for years。 The breakthrough could enable cleaner air purification, solar-driven chemistry, and advanced manufacturing technologies using nothing more than natural sunlight
Astronomers may have witnessed one of the rarest and most dramatic cosmic events ever seen: a long-sought intermediate-mass black hole ripping apart a dense white dwarf star and devouring it。 The Einstein Probe space telescope caught the explosion in its earliest moments, revealing an unusual sequence of intense X-ray flashes unlike anything seen i
The Torifune asteroid turns out to be shaped like a peanut
The discovery underscores the increased effort being poured into Mac infostealers
Scientists have uncovered new evidence that fireworks can pollute both the air and water in ways that extend beyond the visible smoke。 The findings show that leftover debris, fine particles, and airborne chemicals may affect ecosystems and increase people's exposure to air pollution during major celebrations
Researchers have shown that ultracold atoms can be driven into a strange new quantum state called a fractional Fermi sea, where particles organize themselves in unexpected ways。 The discovery points to a new phase of matter that goes beyond established quantum theories and could expand the possibilities of quantum simulation
A new quantum device can generate precisely controlled bursts of sound-like particles, or phonons, by forcing electrons through an ultra-thin crystal at extremely low temperatures。 The surprising behavior pushes beyond the limits predicted by current theories, suggesting scientists need to rethink how energy moves through advanced materials。 In the
A new study suggests Earth may have been sending tiny hitchhikers to Venus for billions of years。 Researchers found that asteroid impacts could launch microbes into space, where some might survive the journey and end up suspended in Venus' clouds。 If future missions detect life there, there's a surprising chance it didn't originate on Venus at all—
Two newly confirmed "super-puff" planets are so diffuse that they are less dense than cotton candy, despite being about the size of Jupiter。 Their rare orbital relationship and enormous, lightweight atmospheres could provide valuable clues about how some of the strangest planets in the galaxy come to exist
Astronomers have finally cracked the mystery of the famous “Pink Planet,” a strange world 57 light-years away that has puzzled scientists for more than a decade。 Using the James Webb Space Telescope, researchers discovered that its atmosphere contains water vapor, methane, carbon dioxide, ammonia, and something never directly confirmed before in su