Downchirped regenerative amplification of femtosecond laser pulses at 100 khz repetition rate

Abstract

. Ti: Sapphire laser technology has provided practical solutions of solid-state femtosecond light source with high average power as well as high peak power. Especially, compact high-average-power femtosecond lasers with a high repetition rate (kilohertz range) are good tools for basic and applied science. Typical high-repetition-rate . Ti: Sapphire amplification lasers using electro-optic pulse selection method operate at 1-10 kHz [1]-[3] with an energy of ~mJ, whereas those using acousto-optic pulse selection method can operate at 100-250 kHz with an energy of J. As for the 100-250 kHz Ti:sapphire amplification system, the regenerative amplifier setup suggested by Norris [4] has been a conventional configuration. Several features of the lasers based on Norris's amplifier configuration can be described as follows: First, they are pumped by a continuous-wave (CW) green laser and intracavity Q-switched for the suppression of prelasing. Second, the high-repetition-rate pulse injection and dumping is achieved by the acousto-optic cavity dumper composed of a Brewster-angle Bragg cell and an RF driver. Third, the dispersion control of the amplification system has been achieved either without [4],[5] or with [6] a chirped-pulse amplification (CPA) technique [7]. In the case of non-CPA systems, pulses are naturally broadened and compressed by use of prism pairs, whereas, in the case of CPA system, transmission gratings are used for both stretching and compression. Adaptive control has been also applied for the non-CPA system to compress the laser pulse down to 35 fs [8]. ? 2007 Springer-Verlag New York.