Femtosecond Phase and Amplitude Controlled, Chirped Pulse Amplification: Terawatts to Petawatts

Chirped pulse amplification at 10 fs and powers > 1 TW faces many challenges. In conventional CPA systems, uncompensatable phase errors in the expansion and recompression process and distortions due to refractive optics produce broadenings which are much greater than 10 fs. In order to alleviate these problems, a novel expander/compressor design has been developed and a lens-free amplification system has been constructed. In addition, gain narrowing during amplification severely limits the final pulse duration. In order to control the pulse spectrum before amplification and thus minimize this problem, spectral masks have also been developed and implemented. The result is a compact multiterawatt laser system capable of producing 125-mJ, 30-fs, 800-nm pulses with near diffraction limited beam quality at a repetition rate of 10 Hz. Ongoing experiments with this 4 TW system include hard x-ray generation for diagnostic imaging, tunneling ionization XUV lasers, and tunable ultrashort pulse, high power IR generation. Because the design of this system can accommodate much larger bandwidth pulses and very large amounts of dispersive material, it is possible to directly scale these results to shorter durations and petawatt peak powers. Such a system could be constructed from currently available optical materials and components and would be capable of producing focused intensities > 1022 W/cm2.