Near diffraction limited 100 TW-10 Hz femtosecond laser. New approaches towards ultra-high intensities

Summary form only given. The chirped pulse amplification method reduced dramatically non-linear effects, enabling thereby higher amplification levels. But when increasing average power needed to pump the Ti:sapphire amplifier crystals, strong thermal effects appear which affect beam propagation by inducing unwanted wavefront distortions. Moreover, amplification process narrows the spectrum of a chirped pulse because of gain narrowing and gain saturation effects. Our laser chain is composed of a Kerr lens mode locked Ti:sapphire laser oscillator delivering a 80 Mhz/300 mW a pulse train with a spectrum of 65 nm FWHM centered around 810 nm. Pulses are stretched through an Offner triplet, and amplified at -10 Hz through three multipass amplifiers to reach, first the millijoule regime through a high-gain amplifier.