Amplification of femtosecond laser pulses beyond the gain narrowing limit

Summary form only given. Titanium:sapphire based oscillator-amplifier systems employing chirped-pulse amplification techniques are useful for compact table-top sources of high-intensity optical pulses. We propose a scheme in which efficient spectral broadening of the pulses will take place in the first few passes of the amplifier. To avoid damage we will substantially stretch the pulses before the last few passes in the first amplifier stage. Residual phase errors will be compensated by newly designed broadband chirped mirrors or/and by the acousto optic programmable dispersive filter (AOPDF). We will present a detailed comparison of the performance for the different employed phase and amplitude shaping devices. Special emphasis is put on the characterization of the spectral phase of the output pulses, the pulse contrast and the beam profile. Based on these investigations we will set up an amplifier system capable of generating intense sub-15 fs laser pulses.