Abstract

We report on a traveling-wave femtosecond optical parametric generator (OPG) pumped near 400 nm that is based on a narrow-band lithium triborate (LBO) seeder. Previously reported femtosecond schemes in this pump- wavelength region were based either on a type-I β-barium borate (BBO) seeder^1,2 or on the substitution of the seeder by a broadband continuum source.³ The unprecedented high damage threshold of LBO (>30 TW/cm²) reported recently for sub-200-fs pulse durations⁴ makes this material a most suitable OPG candidate especially for long-term operation and for scaling to low pump energies in the femtosecond regime, where an upper limit to the crystal length is set by group-velocity-mismatch (GVM) effects.

© 1995 Optical Society of America