Intensity Fluctuations and Mode Correlations in Broadband Dye Lasers

The light produced by free running broadband dye lasers is found to exhibit interesting statistical properties due to fluctuations in mode amplitudes and competition between modes. We have studied these phenomena by measuring the intensity autocorrelation function of a CW standing-wave dye laser. This was accomplished by using a frequency doubling crystal in a cross-beam geometry, giving picosecond time resolution. The intensity autocorrelation function is found to be a highly sensitive probe of the details of mode competition and correlation, which are not apparent in the field power spectrum observed with a conventional spectrometer.