Complete thermal lens control of a 10-100 Hz terawatt system

Summary form only given. We demonstrate a novel 10-100-Hz terawatt source where the thermal distortion is not anymore an issue while varying the repetition rate. The problem of thermal distortion has been already demonstrated for high repetition rates laser as 1-kHz. One recent example for controlling this effect is a thermal eigenmode amplifier where the thermal lens is used to transform a classic multipass amplifier to a real eigenmode cavity. This method has shown very good results in a several mJ, ultrashort Ti:sapphire amplifier laser chain. An amplifier crystal cooled to 125-K has been also demonstrated for a kHz, 0.2-TW laser system. For intermediate repetition rate (10-100 Hz) the thermal aberration is less critical due to the relative high diameter of the pump beam on the amplifier. Nevertheless, it has to be taken into account to preserve a constant high beam quality during amplification.