CW autocorrelation measurements of picosecond laser pulses

Completely general and novel expressions are presented fornth-order fast or slow correlation functions, with or without background contributions, from which more specializednth- and second-order auto-correlation functions are derived. A straightforward method for obtaining CW autocorrelation measurements of picosecond pulses is then described which employs an audio loudspeaker driven at 30 Hz in one arm of the correlator to permit autocorrelation display at this frequency. Results of the application of this device to measurements of the picosecond pulses from a CW synchronously mode-locked Rhodamine 6G dye laser are presented.