Pulse temporal quality improvement in a petawatt Ti: Sapphire laser based on cross-polarized wave generation

Based on cross-polarized wave generation, a robust front-end is designed for improving pulse temporal quality of a petawatt Ti:sapphire laser. High-contrast seed pulses with 105 μJ energy and excellent beam profile can be generated by the front-end. The spectral width of the clean pulses is over 65 nm (FWHM), which can support sub-15 fs pulse duration. Injecting the clean pulses into the petawatt Ti:sapphire laser, the pulse temporal contrast is enhanced from original ~10−8 to 1.7×10−11 (−100 ps before the main pulse), while the recompressed pulse duration is improved to be 27 fs by controlling the spectral evolution in the amplifiers, and the maximum pulse peak power can support ~1.3 PW.