Light scattering

About: Light scattering is a research topic. Over the lifetime, 37721 publications have been published within this topic receiving 861581 citations.

Microscopic correlates of macroscopic optical property changes during thermal coagulation of myocardium

Abstract: The effects of thermal coagulation on the macroscopic optical transport parameters that govern the distribution of light in tissues were studied. The optical absorption coefficients, pa, and the reduced scattering coefficients, j.ts (1-g), were deduced from measurements of total transmission and total reflectance of HeNe laser radiation ( = 633 and 594 nm) directed to thin slices of dog myocardium heated in vitro. The first optical changes were detected at 45°and, at temperatures above 65°, there was a 2-fold increase in absorption and a 7-fold increase in scattering. Transmission electron microscopy of laser-induced thermally coagulated lesions in rat myocardium (cw argon ion, = 514 nm) revealed ultrastructural alterations that were considered responsible for the increased scattering based on Mie theory. These microscopic alterations included disruption of mitochondria to form aggregates of electron dense granules and granular transformation of thermally coagulated proteins of the sarcomeres and cytoplasm. Our preliminary analyses suggest that the mitochondrial granules and the protein granules contribute to the increased scattering oflight in thermally coagulated myocardium.

Fast-response and scattering-free polymer network liquid crystals for infrared light modulators

Abstract: A fast-response and scattering-free homogeneously aligned polymer network liquid crystal (PNLC) light modulator is demonstrated at λ=1.55 μm wavelength. Light scattering in the near-infrared region is suppressed by optimizing the polymer concentration such that the network domain sizes are smaller than the wavelength. The strong polymer network anchoring assists LC to relax back quickly as the electric field is removed. As a result, the PNLC response time is ∼250× faster than that of the E44 LC mixture except that the threshold voltage is increased by ∼25×.

Disorder-induced coherent scattering in slow-light photonic crystal waveguides.

Abstract: Light transmission measurements and frequency-delay reflectometry maps for GaAs photonic crystal membranes are presented and analyzed, showing the transition from propagation with a well-defined group velocity to a regime completely dominated by disorder-induced coherent scattering. Employing a self-consistent optical scattering theory, with only statistical functions to describe the structural disorder, we obtain excellent agreement with the experiments using no fitting parameters. Our experiments and theory together provide clear physical insight into naturally occurring light localization and multiple coherent-scattering phenomena in slow-light waveguides.

Theory of the Refraction and the Diffraction of Neutrons by Crystals

Abstract: The equations for the elastic scattering of neutrons by a single crystal, governing simple refraction, reflection, and Laue-Bragg scattering, are derived under the assumption that the scattering and absorption cross sections are independent of spin. A brief summary of the results is given in the final section of the paper.