Analysis of a synchronously mode-locked and internally frequency-doubled CW dye laser

We present analytical studies of a synchronously mode-locked and internally frequency-doubled CW (SMLFD) dye laser. The analysis describes the cavity detuning behavior of the pulse duration and the square of its peak intensity (the signal intensity of the autocorrelation trace) in terms of system parameters for different lengths of the intracavity crystal. The results predict the broadening of the pulse duration with the increase of the crystal length even though the condition of the group velocity matching is satisfied. It is shown that the prediction is in good agreement with the experimental results of the SMLFD rhodamine 6G laser with an ADP crystal in the cavity. Furthermore, the variation of the minimum pulse duration at the optimum cavity length as a function of the harmonic conversion efficiency is derived.