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.

All-optical on-chip sensor for high refractive index sensing

Abstract: A highly sensitive sensor design based on two-dimensional photonic crystal cavity is demonstrated. The geometric structure of the cavity is modified to gain a high quality factor, which enables a sensitive refractive index sensing. A group of slots with optimized parameters is created in the cavity. The existence of the slots enhances the light–matter interactions between confined photons and analytes. The interactions result in large wavelength shifts in the transmission spectra and are denoted by high sensitivities. Experiments show that a change in refractive index of Δn ∼ 0.12 between water and oil sample 1 causes a spectral shift of 23.5 nm, and the spectral shift between two oil samples is 5.1 nm for Δn ∼ 0.039. These results are in good agreement with simulations, which are 21.3 and 7.39 nm for the same index changes.

Dispersion of the Refractive Index near the Fundamental Absorption Edge in PbS

Abstract: A peak in the wavelength dependence of the index of refraction resulting from the increase in the extinction coefficient at the absorption edge has been observed in PbS The results were obtained by analysis of the reflection spectra of $n$-type single crystal film and bulk samples At 300\ifmmode^\circ\else\textdegree\fi{}K the refractive index at the peak is approximately 7% larger than the square root of the optical dielectric constant The peak moves with the absorption edge with decreasing temperature The optical dielectric constant at room temperature was found to be 168

Three-layered metallodielectric nanoshells: plausible meta-atoms for metamaterials with isotropic negative refractive index at visible wavelengths

Abstract: A three-layered Ag−low-permittivity (LP)−high-permittivity (HP) nanoshell is proposed as a plausible meta-atom for building the three-dimensional isotropic negative refractive index metamaterials (NIMs). The overlap between the electric and magnetic responses of Ag−LP−HP nanoshell can be realized by designing the geometry of the particle, which can lead to the negative electric and magnetic polarizabilities. Then, the negative refractive index is found in the random arrangement of Ag−LP−HP nanoshells. Especially, the modulation of the middle LP layer can move the negative refractive index range into the visible region. Because the responses arise from the each meta-atom, the metamaterial is intrinsically isotropic and polarization independent. It is further found with the increase of the LP layer thickness that the negative refractive index range of the random arrangement shows a large blue-shift and becomes narrow. With the decrease of the filling fraction, the negative refractive index range shows a blue-shift and becomes narrow while the maximum of the negative refractive index decreases.

Surface plate treatment film and display device and its manufacture

Abstract: PURPOSE: To form a reflection preventive/static preventive/leakage electromagnetic field reducing film on a surface base body of a display device. CONSTITUTION: A high refractive index layer 2 and a low refractive index layer 3 are formed in this order between a surface board (a base body) 1 of a display device and an air layer 4, and reflection prevention of external light and static prevention or reduction in a leakage electromagnetic field are performed. The high refractive index layer 2 has the density distribution becoming small in order toward the low refractive index layer 3 from the surface board 1 side, and forms a graded film structure whose refractive index becomes continuously small between it and the air layer 4 from the display panel 1 side together with the low refractive index layer 3.