Kinematic mode locking in a cw YAG:Nd ring laser

An experimental investigation was made of undirectional and bidirectional emission from a ring laser having a resonator perimeter that varied periodically at a frequency of 250 Hz and an amplitude of up to 250μ. It was found that the most favorable conditions for mode locking in this laser occur when the perimeter is varied by moving one of the resonator mirrors. It was established by means of calculations that there is minimal coupling whereby the mode locking stability is ensured in the bidirectional emission regime.