Adaptive control of pulse phase in a chirped-pulse amplifier

Using experimental feedback, we demonstrate that a chirped-pulse amplifier can adaptively learn to compensate for the higher-order phase dispersion th at is inherent in the amplification process. A genetic algorithm-based sear ch routine is used to repetitively update the pulse phase in a programmable pulse stretcher during a plasma breakdown experiment to maximize the magni tude of spectral blueshift. Reductions in pulse duration from 37 to 30 fs a nd substantially better wing structure are typically obtained as a result o f the optimization. (C) 1998 Optical Society of America.