1 kHz solid state laser system for the generation of 50 fs pulses tunable in the visible

Tunable visible pulses with pulse lengths as short as 50 fs were generated with 1 kHz repetition rate and energies between 25 and 300 nJ by up-conversion of near infrared pulses. The latter were derived from the 100 fs output pulses of a regeneratively amplified Ti:sapphire laser system by travelling wave parametric generation and amplification. The conversion scheme produces such short visible pulses with nearly Fourier transform limited bandwidth because the initial parametric processes in the infrared possess extremely low group velocity mismatch even at the necessary crystal lengths of some millimeters and the subsequent up-conversion proceeds in very thin crystals. It is argued that the total scheme can be scaled simultaneously to higher energies, even shorter pulses, and a complete coverage of the visible spectral range.