The sign of the refractive index of any medium is soley determined by the requirement that the propagation of an electromagnetic wave obeys Einstein causality. Our analysis shows that this requirement predicts that the real part of the refractive index may be negative in an isotropic medium even if the electric permittivity and the magnetic permeability are both positive. Such a system may be a...

A semi-analytical technique to determine the propagation constant of periodically segmented Ti:LiNbO3 waveguide (PSW) is described. The 2-D refractive index profiles of the waveguide segments are computed from its fabrication parameters, such as, Ti-layer thickness and width, and the diffusion parameters. WKB method is used to transform 2-D refractive index profile to 1D lateral effective index...

Reflection statistics have not been well studied for optical random media whose mean refractive indices do not match with the refractive indices of their surrounding media. Here, we theoretically study how this refractive index mismatch between a one-dimensional (1D) optical sample and its surrounding medium affects the reflection statistics in the weak disorder limit, when the fluctuation part...

In the open ocean, many animals are highly transparent, some achieving near invisibility. However, little is known about how this transparency is attained. The effects of cellular ultrastructure on tissue transparency were mathematically modeled. Given a specific constant volume or surface area of a higher refractive index material (e.g. protein, lipid, etc.), within a lower refractive index cy...

For several years we have been studying the use of Fabry-Perot interferometers for precise measurement of the refractive index of gasses, where the primary motivation has been to improve interferometer-based length measurement. Because the refractive index of a gas depends on its pressure and temperature, we can also use refractive index to monitor either of these quantities if the second is kn...

Thin ( ~ 1/xm) crystalline ZnO films with a good optical quality and a good (0002) texture are grown under two considerably different process parameter sets using a r.f. planar magnetron sputtering unit. The optical parameters of the two corresponding ZnO layers are distinctly different: high refractive index ( 2.0 at A = 632.8 nm) ZnO films resembling the single crystal form, and ZnO films wit...

background: whispering gallery modes (wgm) biosensors are ultrasensitive systems that can measure amount of adsorbed layer onto the micro-cavity surface. they have many applications including protein, peptide growth, dna and bacteria detection, molecular properties measurements and specific interaction and drug table recognitions due to their high sensitivity, compact size and label free sensin...

The question of whether two sets of measurements which constitute evidence come from the same source is one which is frequently sought to be answered by the forensic community. A common type of evidence comes in the form of glass fragments where the refractive index or elemental composition has been measured The most common way of evaluating trace evidence such as glass fragments is the likelih...

The ray-tracing technique can be employed to simulate the scattering of light by a dielectric particle whose characteristic dimension is much larger than the incident wavelength. When a scattering particle is absorptive, a localized electromagnetic wave refracted into the scatterer is inhomogeneous, which requires the use of an effective refractive index to determine the propagation direction o...

A high sensitivity refractive index sensor based on a single mode-small diameter no core fiber structure is proposed. In this structure, a small diameter no core fiber (SDNCF) used as a sensor probe, was fusion spliced to the end face of a traditional single mode fiber (SMF) and the end face of the SDNCF was coated with a thin film of gold to provide reflective light. The influence of SDNCF dia...