Ti:sapphire regenerative amplifier

The design and performance of a stable Ti:sapphire regenerative amplifier, 7mJ (800 nm) per pulse at the repetition rate 10 Hz, has been described . The resonator consists of one concave mirror (k=4000mm) and one plane mirror, spaced at a distance of 1.76 m. The two mirrors are coated for high reflection centred at 800 nm . Two Pockel cells, one broadband waveplate and polarizer are used to switch a pulse into and out of the resonator. The Ti:sapphire crystal rod is 6x6x14 mm with an absorption coefficient of 2.6 cm"¹ at 490 nm and both sides is cut at Brewster's angle. The pump source is frequency double Nd:YAG laser. For regenerative amplifier, the pump energy which we usually use is 64 mJ per pulse. The seed pulse is from a self-mode-locked Ti:sapphire laser that provides 400 mW of outpower with pulse duration about 80-100 fs . After stretching the pulse to about 200-300 ps by using the grating stretcher, we inject the pulse into the regenerative amplifier and obtain 7mJ output energy in single pulse, a net gain of up to 10⁶. This laser system is a pre-amplifier for high energy amplifier.