High-quality, 1-kHz, 20-fs, 0.15-TW Ti:sapphire laser with a single-stage amplifier

Abstract

We have demonstrated the generation of 20-fs, 0.15-TW laser pulses with high temporal and spatial qualities from a kHz femtosecond Ti:sapphire laser system with a single-stage amplifier. A maximum output energy of 4.1 mJ could be achieved from the amplifier by suppressing the thermal lensing effect. A spectral bandwidth of 57 nm was obtained by maximizing the reflection bandwidth that the amplifier could support and by compensating for gain narrowing. A temporal profile close to the Fourier-transform-limited pulse profile was obtained by minimizing the spectral phase error, and the pulse duration was 20 fs at full width at half maximum. The measured beam quality factors were 1.2 and 1.4 in the horizontal and the vertical directions, respectively.