Step-index profile

About: Step-index profile is a research topic. Over the lifetime, 3104 publications have been published within this topic receiving 53199 citations.

Fiber Loop Ring-Down Refractive Index Sensor Based on High- $Q$ Photonic Crystal Cavity

Abstract: This paper proposed a novel ultracompact refractive index sensor formed by a high-quality (Q) photonic crystal (PhC) cavity-based fiber loop ring-down. In our proposed device configuration, we insert one pair of two air holes into the linear waveguide as two reflectors, and a point defect was defined between the two reflectors to form a nanocavity. Since the output resonant spectrum was extremely sensitive to a small refractive index variance attributed to the medium infiltrated in the holes, the ring-down time as well as the radiation intensity would be a function of the relative refractive index for input light at certain frequency. To improve the system sensitivity, the Q -factor of nanocavity was optimized by adjusting the radii of all air holes and the spacing between the two reflectors. The properties of the refractive index sensor were analyzed and simulated using the finite-difference time-domain method. Results showed that a quasi-linear measurement of refractive index was achieved with sensitivity of 20.34 ms per refractive index unit and Q -factor of 605. In addition, the sensing range could be broadened to 1.330-1.400 by using multiple operating frequencies.

Method of adjusting refractive index distribution lenses

Abstract: The refractive index distribution in refractive index distribution lenses may be adjusted to better approach an ideal by heating the refractive index distribution lens. When the refractive index distribution lens was created by diffusion of refractive index changing ions into a body, further heating in an environment in which no additional ions can diffuse into the body causes further migration of ions within the body so that its refractive index distribution approaches an ideal.

Optical waveguide device

Abstract: An optical waveguide device comprises a low refractive index layer (8) having a refractive index nb, a core layer (6-1, 6-2) having a refractive index nc (where nc> nb) and a cladding layer (9) having a refractive index nc1 (where nc1< nc) formed on a substrate (7). Thermal expansion coefficients of the low refractive index layer (8), the core layer (6-1, 6-2) and the cladding layer (9), respectively, are made substantially equal to each other at respective boundaries.

Two-dimensional/three dimensional image display screen

Abstract: PROBLEM TO BE SOLVED: To provide a two-dimensional/three-dimensional display screen which is provided with and not provided with optical directivity by changing the electric field to be impressed on a refractive index change layer by transparent electrodes, thereby changing the refractive index of this refractive index change layer to the value nearly same as the value of a lens layer or a value different therefrom. SOLUTION: A lenticular lens plate 1 for changing the progressing direction of light and a refractive index variable material 2 variable in the refractive index are superposed on each other. Whether the refractive index of this refractive index variable material 2 is made the same as the refractive index of the lenticular lens plate 1 or the value different therefrom is embodied by switching the magnitude of the electric field to be impressed on the refractive index variable material 2, i.e., the magnitude of the voltage to be impressed on the transparent electrodes 3. As a result, a lens effect is developed by the voltage impression when the refractive indices of both are varied and a transparent plate, such as mere glass plate, is obtd. if the refractive indices are the same.