Topic
Refractive index
About: Refractive index is a research topic. Over the lifetime, 51519 publications have been published within this topic receiving 774041 citations. The topic is also known as: index of refraction & IOR.
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TL;DR: The nonlinear index of refraction is responsible for self-action effects in optical beam propagation, including self-focusing as mentioned in this paper, and the physical mechanisms that give rise to the refractive index nonlinearity.
Abstract: The nonlinear index of refraction is responsible for self-action effects in optical beam propagation, including self-focusing. We review self-focusing and related phenomena and discuss physical mechanisms that give rise to the refractive index nonlinearity.
957 citations
TL;DR: In this article, a two-hand model is used to calculate the scaling and spectrum of the nonlinear absorption of semiconductors and wide-gap optical solids, and the bound electronic nonlinear refractive index n/sub 2/ is obtained using a Kramers-Kronig transformation.
Abstract: A two-hand model is used to calculate the scaling and spectrum of the nondegenerate nonlinear absorption. From this, the bound electronic nonlinear refractive index n/sub 2/ is obtained using a Kramers-Kronig transformation. The authors include the effects of two-photon and Raman transitions and the AC Stark shift (virtual band blocking). The theoretical calculation for n/sub 2/ shows excellent agreement with measured values for a five-order-of-magnitude variation in the modulus of n/sub 2/ in semiconductors and wide-gap optical solids. Beam distortion methods were used to measure n/sub 2/ in semiconductors. The observations result in a comprehensive theory that allows a prediction of n/sub 2/ at wavelengths beneath the band edge, given only the bandgap energy and the linear index of refraction. Some consequences for all-optical switching are discussed, and a wavelength criterion for the observation of switching is derived. >
956 citations
942 citations
TL;DR: In this article, the authors describe an all-angle negative refraction effect that does not employ a negative effective index of refraction and involves photonic crystals, and demonstrate this phenomenon using a microsuperlens.
Abstract: We describe an all-angle negative refraction effect that does not employ a negative effective index of refraction and involves photonic crystals. A few simple criteria sufficient to achieve this behavior are presented. To illustrate this phenomenon, a microsuperlens is designed and numerically demonstrated.
914 citations
TL;DR: In this paper, it is shown how these properties can be explained by the assumption that the molecules are arranged in a special way, so that the electrical axes rotate screw-like.
Abstract: A group of liquid crystals, mainly derivates of cholesterol, shows remarkable optical properties, including strong rotatory power and selective reflexion of circularly polarized light in a narrow region of wave-lengths. In this paper it is shown how these properties can be explained by the assumption that the molecules are arranged in a special way, so that the electrical axes rotate screw-like. It is inessential whether this occurs in small steps or continuously. When the axes make one revolution over a thickness p, then light in a region around λ=pn will be reflected (n = refractive index). The second important parameter is the value of the double refraction α = (n 2 - n 1)/n. From p and α all optical properties can be calculated. No accurate data for testing the theory are available but qualitatively the agreement is complete.
905 citations