Phase-contrast optothermal IR spectrometer

An automated IR spectrometer was constructed on the basis of a pulsed optical parametric oscillator tunable in the range 1.5 — 3.7 μm. An interferometer optothermal method with a phase-contrast system for recording the signal was adopted. When the energy of the parametric oscillator radiation was 10 mJ, the minimum detectable absorption coefficient was α ~ 10^–6 cm^–1