No abstract

We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by well-compressed spectral-phase fully-compensated fundamental laser pulses, the filter stretches the pulse bandwidth from 35 nm to 70 nm with a conversion efficiency of 20%. After implementing the filter into a femtosecond TW Ti:sapphire laser system, we generate 40 mJ output pulse energy with pulse duration of 18.9 fs. The temporal contrast of the compressed pulse is enhanced to 109.

To meet the application requirements for high energy kHz repetition rate femtosecond laser, a high-efficiency femtosecond Ti:sapphire linear regenerative amplifier is designed. By optimizing the parameters of the cavity, 5.8 mJ chirped pulses at 800 nm are obtained, under pump energy of 20 mJ with wavelength of 527 nm at 1 kHz repetition rate, corresponding to a slope efficiency of 30.7%. By compensating for the dispersion, 4 mJ laser pulses at 800 nm with pulse duration of 45.7 fs are achieved. The energy fluctuation is 0.18% (RMS) in 5 h.