Generation of chirped pulses at high repetition rate with a Ti: sapphire regenerative amplifier

We present a method to obtain a laser pulse train at high repetition rate for the Ti: sapphire laser system based on the chirped pulse amplification technique. The conventional working mode of the Pockels cell in the Ti: regenerative amplifier is modified. At a certain dumping time, a portion of the amplified seed pulse is dumped out of the cavity by a certain dumping ration every time the pulse runs around the cavity. Thenceforward, the chirped pulses at high repetition rate are generated. Based on the Franz-Nodvik amplification theory, a theoretical model of the regenerative amplifier is established and the analysis of the dependence of the pulse sequence on the dumping time and dumping ratio is given by numerical computation. With a pumping energy of 35 mJ and a dumping ratio of 1/2, a fourteen-pulse sequence at 100 MHz with pulse energy of 0.02 mJ is obtained at a finite period of time in a pumping cycle.