Emission spectrum of a YAG:Nd3+ laser with a vibrating resonator

It is shown theoretically and experimentally that one of the reasons for kinematic mode locking in a YAG:Nd³⁺ laser is the change in the emission spectrum due to the interaction between modes via the inverted population of the active medium. Broadening of the spectrum at mirror vibration frequencies from 0.2 to 4 kHz was observed. When the amplitude of these vibrations was 22 μ and the frequency was 0.5 kHz, the width of the spectrum increased by a factor of 3. A calculation carried out for seven longitudinal modes showed that a redistribution of the energy in the emission spectrum suppressed the central modes and excited the side modes.