Optical depth profiling by attenuated total reflection Fourier transform infrared spectroscopy using an incident beam with arbitrary degree of polarization

A depth profiling analysis via multiple angle attenuated total reflection Fourier transform infrared spectroscopy using an incident beam with arbitrary degree of polarization has been developed. A guessed complex refractive index profile is not required for the analysis. The analysis consists of three steps: estimation of the complex refractive index profile by the estimated mean square electric field, linear least square fitting of absorptances, and nonlinear fitting of reflectances. The applicability of this approach with various types of profile and degrees of polarization has been shown by simulated spectra with added white noise. The effect of amplitudes of noise on the accuracy of this approach has been investigated.