DETERMINATION OF THE OPTICAL CONSTANTS AND RELATED FACTORS OF DIAMOND FROM TRANSMISSION MEASUREMENTS

By combining the reality of CVD diamond,transmittance model of free standing diamond films was derived.In the model,several factors affect transmittance such as chromatic dispersion, optical non-uniformity, surface roughness and absorption of the graphite （free carries） and carbon-hydrogen bonding in the sample-were considered.IR spectra of diamond was non-linear least square fitted（NLSF） by Levenberg-Marquardt algorithm.Reliable frequency dependence of n and k, together with thickness,surface roughness,impurities and microstructure were then obtained.This result will be important for a correct analysis of the IR properties of diamond films.