Abstract

LBO crystal is transparent up to 165 nm, making it a very good nonlinear crystal in the UV region—better than BBO crystal. Still, it has a smaller double refraction coefficient than BBO (0.12). Thus efficient phase-matching UV frequency conversion requires one of the mixing input wavelengths to be longer than 1.2 m. From this point of view, an intense near-infrared source is needed, so we developed a system that can output 1.55μm picosecond pulses with an intensity of MW/cm² by means of stimulated Raman scattering. The fourth harmonic was mixed with 1.55-m SRS output in LBO crystal. Being dispersed by grating, the UV output (2200 Å) can be measured easily. With the same infrared source, we can generate vacuum violet output (1850 Å) picosecond pulses by mixing with the fifth harmonic of a Nd:YAG laser.

© 1990 Optical Society of America