Electric-field correlation of femtosecond pulses by use of a photoelectromotive-force detector

A semiconductor photoinduced electromotive-force detector is used to measure the square of the electric-field correlation of nominal 100-fs laser pulses. For transform-limited pulses, this measurement gives the intensity correlation and thus directly gives the pulse width. The photoinduced electromotive-force technique using semi-insulating GaAs:Cr performs detection that is linear in intensity, making it possible to characterize weak femtosecond pulses with an average power of microwatts.