High-power LiNbO3 optical parametric oscillator for resonant infrared laser chemistry

A high-power singly resonant LiNbO₃-crystal optical parametric oscillator has been developed for resonant infrared laser chemistry. By using crystals of high optical homogeneity, a broad (~ 7 mm) pump beam, and a high-Q resonator (λ = 1.35–1.80 μm) with mirrors resistant to optical damage, it was possible to obtain a useful pulse radiation energy of ~ 120 mJ in the 2.5–4.5 μm range. These oscillator characteristics made it possible to use reliably the-time-of flight mass-spectrometric method for diagnostics of dissociation products of macromolecules under conditions of resonant irradiation in bands of CH and OH stretching vibrations of a polymer.