Exploring the Emergence of the Self-Q-Switching in Diode-Pumped Yb:KGW Monolithic Lasers

Abstract

We perform through experiments to explore the key factors for the emergence of a self-Q-switching phenomenon in diode-pumped Yb: KGW lasers. In addition to the output transmission, it is found that the mode-to-pump size ratio is a critical factor leading to the self-Q-switching. The region of the cavity mode volume without overlapping the pump volume plays a role of modulation loss to result in self-Q-switching. With an output transmission of 4% and a mode-to-pump size ratio of approximately 1.2, simultaneous self-Q-switching and self-mode-locking with the repetition rate of 23.1 GHz were experimentally observed. At an incident pump power of 9.2 W, the maximum pulse energy was estimated to be 1.4 mu J at the repetition rate of 880 kHz with an average output of 1.27 W.