Development of an infrared absorption measurement method using the photothermal deflection effect of thallium bromide iodide (KRS-5): Measurement with a stepped-scan Fourier transform infrared spectrometer

An optical system was produced experimentally for infrared absorption measu rements based on the photothermal deflection effect of solid material (KRS- 5), which does not require a cell for the medium as does absorption measure ment using the photothermal deflection effect of liquids. In this study, it was shown that the photoelastic effect of photothermal beam deflection exi sts in KRS-5 crystals, and the necessity of regulating the polarization dir ection of the laser beam is described. Infrared absorption spectral measure ments were done on several samples using a stepped-scan Fourier transform i nfrared spectrometer for the evaluation of this technique. The results agre ed well with the results of transmittance measurements of the same samples. In conclusion, this new technique seems to be useful for the measurement o f infrared absorption. (C) 2001 American Institute of Physics.