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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.
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TL;DR: In this article, the optical absorption coefficients and refractive index changes in a two-electron quantum dot with oscillating and linear confining terms are obtained by using compact-density matrix approach and exact analytical method.
Abstract: Analytical expressions of the optical absorption coefficients and refractive index changes in a two-electron quantum dot with oscillating and linear confining terms are obtained by using compact-density matrix approach and exact analytical method. Numerical results on typical GaAs/AlGaAs materials show that, an increase of the confinements blueshifts the peak positions of absorption coefficients and refractive index changes. Additionally, an increase of the optical intensity and relaxation time considerably changes the absorption coefficients as well as the refractive index changes.
82 citations
TL;DR: The nature of the coupled cladding modes close to the dispersion turning point makes the dual-peak LPGs ultrasensitive to cladding property, permitting a fine tailoring of the mode dispersion and index sensitivity by the light cladding etching method using HF acid of only 1% concentration.
Abstract: We have experimentally investigated the mode dispersion property and refractive index sensitivity of dual-peak long-period fiber gratings (LPGs) that were sensitized by hydrofluoric acid (HF) etching. The nature of the coupled cladding modes close to the dispersion turning point makes the dual-peak LPGs ultrasensitive to cladding property, permitting a fine tailoring of the mode dispersion and index sensitivity by the light cladding etching method using HF acid of only 1% concentration. As an implementation of an optical biosensor, the etched device was used to detect the concentration of hemoglobin protein in a sugar solution, showing a sensitivity as high as 20 nm/1%.
81 citations
80 citations
TL;DR: The increase in the refractive index and the coefficient of absorption was investigated and was found to demonstrate saturation with increased exposure time, and as high as 0.05, or 2%, were obtained in As2Se3, a promising glass for all-optical switching.
Abstract: Photodarkening of amorphous As2Se3 thin films was generated by a 633-nm HeNe laser. The refractive index and absorption coefficient of the chalcogenide glass was determined, both before and after exposure, by analyzing the material's transmission spectrum. In order to accurately determine the optical constants, the thin film's non-uniform thickness was accounted for. The increase in the refractive index and the coefficient of absorption was investigated and was found to demonstrate saturation with increased exposure time. Index changes as high as 0.05, or 2%, were obtained in As2Se3, a promising glass for all-optical switching.
80 citations
Patent•
04 May 2011TL;DR: An optical member including high refractive index layers having a great as discussed by the authors and low as discussed by the authors having a small as discussed by the authors, which are each relatively thin as compared with an optical length, disposed alternately in the lateral direction as to an optical axis.
Abstract: An optical member including high refractive index layers having a great refractive index and low refractive index layers having a small refractive index, which are each relatively thin as compared with an optical length, disposed alternately in the lateral direction as to an optical axis. Each width of the high refractive index layers and the low refractive index layers is equal to or smaller than the wavelength order of incident light.
80 citations