Tunable mid-infrared spectrometer based on KTA crystal to study fundamental v

Abstract

Tunable mid-infrared radiation in the range 3-3.5 μm have been generated by difference frequency mixing in a biaxial potassium titanyl arsenate (KTA) crystal. The fundamental input radiations are the second harmonic of a commercially available Nd:YAG laser radiation (i.e. 532 nm) and the same pumped visible dye laser radiation. Using the generated tunable radiation the room temperature absorption spectra of R-branch of the v3 band of methane at 120 mbar pressure have been studied. Pressure dependent absorption of P(7) line of the v3 band of methane have also been studied. The absorption measurements have been performed in an indigenously built single pass gas cell of length 33 cm.