Spectroscopic and nonlinear-optical applications of a tunable β-barium borate optical parametric oscillator

A pulsed β-barium borate optical parametric oscillator (BBO OPO) serves as the tunable source of coherent radiation for linear- and nonlinear-optical spectroscopic applications: photoacoustic absorption, optical double resonance, and coherent Raman spectroscopy. The BBO OPO is used spectroscopically either as a free-running broadband device with single-shot multiplex detection or as a continuously tunable narrow-band device controlled by injection seeding. A single BBO crystal offers a wide fundamental OPO tuning range (0.41–2.7 μm) that can be extended further into the ultraviolet and infrared regions by additional nonlinear-optical stages. Pumped at 355 nm by a single-mode Nd:YAG laser, the BBO OPO operates with high conversion efficiency and damage threshold and adequate beam quality for spectroscopic and nonlinear-optical purposes.