Stable argon laser with phase mode locking

An investigation was made of the mode composition and time characteristics of an argon laser with an intracavity electrooptic modulator tuned to the intermode beat frequency. The parameters of the intracavity interaction needed to ensure stable phase mode locking were determined. Several carriers appeared in the frequency-modulated spectrum in the case of multifrequency free running. These carriers were attributed to the presence of supermodes in the gain profile of the active medium. Amplitude modulation of the radiation at the frequency of 0.5 MHz was observed and it was explained by coherent addition of carriers in the frequency-modulated spectrum.