High efficiency and narrow line width operation of barium and lithium borate optical parametric oscillators

Optical parametric oscillators of BBO and LBO have been optimized for high efficiency, narrow line width, and wide tunability. Pumped by the second, third and fourth harmonic of an injection-seeded Nd:YAG laser (Spectra Physics, model GCR-5) the BBO-OPO generates widely tunable radiation (300–3000 nm) with total pulse energies of typically 100–200 mJ. Using 12, 15, and 18 mm long crystals, optimized internal efficiencies are as high as 72%.