An analytical expression for the difference in buildup time between two longitudinal modes in a passively <i>Q</i> -switched laser resonator is developed and compared with experimental laser data. The results support the following temporal criterion for single-frequency, passively <i>Q</i> -switched operation: The difference in buildup time between any two longitudinal modes of the laser resonator should be comparable with or greater than the laser pulse duration to ensure single-frequency operation.
© 1999 Optical Society of America
Y. Isyanova and D. Welford, "Temporal criterion for single-frequency operation of passively Q-switched lasers," Opt. Lett. 24, 1035-1037 (1999)