PARAMETRIC GENERATION IN BETA-BARIUM BORATE OF INTENSE FEMTOSECOND PULSES NEAR 800 NM

We use amplified colliding-pulse, mode-locked dye-laser pulses of 150-mu-J energy to pump a two-stage, single-path parametric converter of beta-barium borate (beta-BBO). The wavelength-noncritical phase-matching condition in beta-BBO at 620 nm permits generation of 200-fs signal pulses with at least the bandwidth of the pump. At 830 nm the overall energy conversion efficiency is 17%. This is an efficient, tunable way to produce near-IR pulses as an alternative to continuum generation. The signal is used for amplification in IR dye and titanium-sapphire and for continuum generation. The input/output characteristics of the parametric generator are presented. Additionally, we observe off-axis parametric generation followed by sum-frequency generation for pump pulse intensities larger than 5 GW/cm2.