Phase-locking phenomena of multitransverse, longitudinal modes in He-Ne lasers

This paper presents experimental results and theoretical considerations about the phase-locking phenomena of multitransverse, longitudinal modes. We first show the mechanism of the self-locking phenomenon of these modes, considering the frequency and the phase relationship between the fundamental modes and the combination tones. Experiments indicate the occurrence of such a phenomenon in TEM
01
+ TEM
10
modes. We next mention the behavior of our type of modes when the loss modulation is applied in the cavity. With the rather asymmetric modes noted above, we enforced the locking of the transverse-mode separation. Further, we observed another type of self-locking phenomenon with TEM
01
+ TEM
10
modes. Each transverse mode is locked independently and the pulses of each mode appear alternatively.