Abstract

Chirped pulse amplification (CPA) has become a common technique for circumventing optical damage and nonlinear effects during the amplification of ultrashort optical pulses in solid state laser media.¹ Ter- awatt level pulses with durations ranging from ~1 ps to ~100 fs have been produced by a number of systems. Although much shorter pulse oscillators exist, the implementation of CPA with pulses on the order of 10 fs has not been accomplished. 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. The result is a laser system which is presently capable of producing —135-mJ, ~30-fs, 800-nm pulses with near diffraction limited beam quality at a 10-Hz repetition rate. It is the first system to produce sub-50-fs multiterawatt pulses and the first to control femtosecond timescale phase and amplitude distortions during terawatt level amplification.

© 1994 Optical Society of America