Specially designed metal-dielectric composites can have a negative refractive index in the optical range. Specifically, it is shown that arrays of single and paired nanorods can provide such negative refraction. For pairs of metal rods, a negative refractive index has been observed at 1.5 μm. The inverted structure of paired voids in metal films may also exhibit a negative refractive index. A s...

In optical tomography, conventionally the diffusion approximation (DA) to the radiative transport equation (RTE) with a constant refractive index is used. The existence, uniqueness, and non-uniqueness of the forward and the inverse problem using conventional DA has been studied in the past. In this report, we investigate the existence, uniqueness, and non-uniqueness of optical tomography forwar...

Gold nanorods (AuNRs), rod-like gold nanoparticles, show strong plasmon bands in the near-infrared region, based on the longitudinal oscillation mode of surface plasmons. In this research, we have coated AuNRs with silica or poly (sodium 4-styrenesulfonate) (PSS) in order to evaluate the effects of surface modifications as a sensing probe material of AuNR. Multilayered assemblies of the PSS-coa...

We present a refractometer based on the principle of total internal reflection that can sensitively record, in real time, the refractive index of fluids over a wide range of refractive indices. The device uses a divergent laser beam and a linear diode array, and has no mechanical or optical moving parts, enabling us to achieve the measurement of a refractive index at a sensitivity level of 10(-...

Large, high efficiency, volume Bragg gratings with dimensions of 5 mm× 5 mm and thickness between 1 and 7 mm with 20 μm pitch have been inscribed in poly(methyl)methacrylate (PMMA) with 180 fs, 387 nm parallel beams using both linear and circular polarizations. Linear polarization (perpendicular to the scan direction) produced the highest refractive index contrast, while circular polarization p...

In this study, a polarization-control setup for intensity-resolved guided mode resonance sensors is proposed and demonstrated experimentally. The experimental results are in good agreement with the simulation data based on rigorous coupled wave approach calculations. The proposed intensity-resolved measurement setup transfers polarization ellipses, which are produced from guided mode resonance ...

Ytterbium-doped metaphosphate laser glasses were prepared by the melt-quenching technique and their optical, thermo-mechanical and laser properties were characterized. Linear and non-linear refractive indices, laserinduced damage threshold, microhardness number and thermal expansion co-efficient have been evaluated for 1.0 mol% Yb2O3-doped glass. Low non-linear refractive index, high laser-indu...

A method to construct modal fields for an arbitrary oneor two-dimensional intensity dependent refractive index structure is described. An arbitrary starting field is propagated along an imaginary axis using the Finite Difference Beam Propagation Method (FDBPM) based upon the Slowly Varying Envelope Approximation (SVEA). First the modes are found for the linear part of the refractive index struc...