Fourier Transform Raman Spectroscopy Using a Tuneable Solid-State Laser and a Semiconductor Bandgap Filter

Abstract

The feasibility of using the optical absorption properties of a semiconductor crystal as a long wavelength pass filter for Fourier transform Raman spectroscopy applications has been demonstrated. Near-infrared excitation from a titanium: sapphire solid-state laser was selectively tuned to the edge of the bandgap absorption of an indium-doped cadmium telluride semiconductor filter. Raman spectra to within 30 cm⁻¹ of the exciting line could be measured. Narrowing of the optical absorption of the semiconductor filter at low temperatures did not improve the “sharpness” of the cutoff performance.