A 12.4 W Ti:sapphire Based Regenerative Amplifier System with 200 fs Pulse Width at 50 kHz Repetition Rate

We have developed a cryogenically cooled Ti:sapphire regenerative amplifier at the repetition rate of up to 100 kHz which was pumped by the intracavity SHG pulses of Yb:YAG thin disk laser. An electro-optic (EO) switching device employing a β-barium borate (β-BBO) crystal was used for pulse extraction from the amplifier resonator. The maximum average amplified power obtained was 21 W under the two pumping pump powers of 70 W at 50 kHz and 75 W at 100 kHz. The amplified pulse was able to be compressed to 200 fs by a grating pair compressor, and the output power was 12.4 W at 50 kHz. The cryogenic cooling system made Ti:sapphire crystal capable to be pumped with over 70 W SHG power in order to keep the stable condition of the regenerative amplifier resonator.