We present an implementation of spectral phase interferometry for direct el
ectric-field reconstruction (SPIDER) which characterizes ultrashort optical
pulses in the spectral or temporal domain at a rate of 20 Hz. This apparat
us was used in real-time as a diagnostic tool to optimize our 1 kHz regener
atively amplified laser system for the shortest duration pulses. (C) 1999 O
ptical Society of America.