Measurement of Infrared Spectra of Dense Ceramics by Specular Reflectance Spectroscopy

Abstract

It is shown that high‐quality IR specular reflectance spectra can be obtained from polished surfaces of dense ceramics. The reflectance spectra can be deconvoluted by the Kramers‐Kronig transformation to yield absorption spectra or the real and imaginary parts of the dielectric function. IR line shapes and peak wavenumbers are comparable to single‐crystal data providing that the particle size is small compared with the IR wavelengths of interest. For noncubic structures, the spectra are a superposition of polarization components. Modes separated by less than a bandwidth are merged into a single band, thus limiting the resolution of the measurement procedure. Grain size effects were modeled using the spectra of single‐crystal and polycrystalline quartz as an example.