Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1988 · 15 citations · 0 references
Natural SciencesMaterials SciencePhysicsMaterials CharacterizationOptical MaterialsOpticsOptical Properties Of MaterialsOptical Properties Of SolidsPhotonic MaterialsPhysical OpticsRefractive IndexThermal Properties Of MaterialsComplex Refractive IndexCrystal Optical ConstantsIndex Of Refraction ModelingIntrinsic PropertiesOptical Absorption CoefficientOptical CharacterizationOptical PropertiesThermo-optic Properties
Current applications of optical window materials require a compre-hensive characterization of the index of refraction and absorption coefficient as a function of frequency and temperature. General models of multiphonon absorption and one-phonon resonances are used to characterize the complex index of refraction of polar crystals. Experimental data from 100 to 5000 cm <sup>-1</sup> at a variety of temperatures are used to determine physically meaningful parameters in the models. Extrapola-tions outside the experimental range of temperature and frequencies are valid. Thus, the model is of great utility. A review of the theory used in this model is given. Results of the application of the model to oxides, fluorides, and alkali halides are also presented. The absorption coefficient from 105 to 10 -5 cm -1 and the index of refraction from radio frequency to visible are obtained.