OPTICAL PARAMETRIC GENERATION AND AMPLIFICATION IN BARIUM BORATE AND LITHIUM TRIBORATE CRYSTALS

A picosecond, widely tunable, optical parametric generator-amplifier s ystem can be constructed with barium borate and lithium triborate crys tals pumped by third- or second-harmonic output of an active-passive m ode-locked Nd:YAG laser. A tunable output of several hundred mirojoule s per pulse with a conversion efficiency as high as 30% has been obtai ned. The tuning range covers from 0.4 to 2.0 or from 0.6 to 2.5 mum an d can be extended by sum- and difference-frequency generation to near 0.2 mum in the UV and to near 8 mum in the IR. The output linewidth ca n be narrowed to near the transform limit with the help of frequency s election a grating