Related papers: A spatial refractive index sensor using whispering…
Long cylinders, such as optical fibers, are some of the most widely used photonic devices. The radius and refractive index of these fibers are therefore fundamentally important parameters in determining their performance. We have developed…
Refractive index is a fundamental optical property of powder and a key input to the measurement of the size distribution using light scattering and the measurement of the absorption and scattering coefficients using diffuse reflectance…
We performed high-resolution Fourier-transform infrared (FTIR) spectroscopy of a polymethyl methacrylate (PMMA) sphere of unknown size in the Mie scattering region. Apart from a slow, oscillatory structure (wiggles), which is due to an…
Flying particle sensors in hollow-core photonic crystal fibers require accurate localization of the optically trapped microparticles. We report position measurement to micrometer-resolution, using optical frequency domain reflectometry, of…
We present a robust, precise, and accurate method to simultaneously measure the refractive indices of two transparent materials within an interference coating. This is achieved by measuring both a photometrically accurate transmittance…
The refractive index of novel organosilica (nano/micro)material is determined using two methods. The first method is based on analysis of optical extinction efficiency of organosilica beads versus wavelength, which is obtained by a standard…
Using a white light interferometric microscope (WLIM) we measure the photodamage induced change in the complex index of refraction of disperse orange 11 (DO11) dye-doped (poly)methyl-methacrylate. We find that the change in the imaginary…
We study the refractive-index sensing properties of plasmonic nanotubes with a dielectric core and ultra-thin metal shell. The few-nm thin metal shell is described by both the usual Drude model and the nonlocal hydrodynamic model to…
Whispering gallery mode microlasers are highly sensitive refractive index sensors widely explored for biophotonic and biomedical applications. Microlaser excitation and collection of the emitted light typically utilize microscope objectives…
Pixel size in cameras and other refractive imaging devices is typically limited by the free-space diffraction. However, a vast majority of semiconductor-based detectors are based on materials with substantially high refractive index. We…
This paper describes the spherical concave mirror method for measuring the index of refraction of transparent liquids. We derived the refractive index equation using Snell's law and the small-angle approximation. We also verified the…
A high sensitivity force sensor based on dielectric microspheres in vacuum, optically trapped by a single, upward-propagating laser beam, is described. Off-axis parabolic mirrors are used both to focus the 1064~nm trapping beam and to…
We deposit thin titanium-nitride (TiN) and TiN/Ti/TiN multilayer films on sapphire substrates and measure the reflectance and transmittance in the wavelength range from 400 nm to 2000 nm using a spectrophotometer. The optical constants…
We demonstrate aqueous refractive index sensing with 15 to 30 {\mu}m diameter silicon nitride microdisk resonators to detect small concentrations of Li salt. A dimpled-tapered fiber is used to couple 780 nm visible light to the microdisks,…
Dry and wet drawing materials were investigated by THz time-domain spectroscopy in transmission mode. Carbon-based and iron-gall inks have been studied, some prepared following ancient recipes and others using current synthetic materials; a…
We measured images and Fourier images of fluorescence for 0.11- and 0.22-$\mu$m-diameter dye-doped polystyrene micro-sphere beads on a solid immersion lens, and experimentally verified strongly-angle-dependent fluorescence intensities due…
A method to engineer the refractive indices of functional materials (TiO2, ZnO, SnO2, SiO2), by nanostructuring in the deep sub-wavelength regime (<20nm), is presented. Block-copolymer templating combined with a wet processing route is used…
We introduce a new approach for measuring both the effective medium and the transport properties of light propagation in heterogeneous media. Our method utilizes the conceptual equivalence of frequency variation with a change in the…
With the development of terahertz time-domain spectroscopy, methods have been proposed to precisely estimate the thickness, refractive index, and attenuation coefficient of a sample. In this article, we propose a new method to compute these…
Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from…