GENERATION OF COMPRESSED 600-720-NM TUNABLE FEMTOSECOND PULSES BY TRANSIENT FREQUENCY MIXING IN A BETA-BARIUM BORATE CRYSTAL

We demonstrate the feasibility of the compression of tunable pulses by means of sum-frequency generation under special group-velocity mismat ch conditions. beta-Barium berate crystal has been shown to support th e upconversion process, resulting in 160-fs pulses tunable within 600- 720 nm when mixing 1.3-ps 1055-nm pulses from a Nd:glass laser with 0. 95-ps pulses tunable within 1400-2200 nm from a traveling-wave paramet ric generator. A similar compression of similar to 150-fs Ti:sapphire pulses predicted for the sum-frequency tuning range of 520-590 nm. (C) 1996 Optical Society of America