Development of a high-contrast,high-peak power,Ti:Sapphire/OPCPA laser system

We report on a high-contrast, high-peak power laser system, which combines both conventional laser amplification and optical parametric chirped pulse amplification (OPCPA) techniques. By employing an OPCPA system after a regenerative amplifier, we have enhanced the prepulse contrast by six orders of magnitude. A prepulse contrast of better than 4.4 × 10^?11 has been measured with a high-energy broadband pulse of 24 mJ at a 10 Hz repetition rate from the OPCPA system. With a subsequent four-pass Ti:sapphire amplifier, we have achieved an amplified energy of 279 mJ and an ultrashort recompressed amplified pulse duration of 23.5 fs. We also discuss the basic design aspects and present our preliminary experimental investigations for higher energy operation to a multijoule.