Enhancing performances of a passively Q-switched Nd:YAG∕Cr^4+:YAG microlaser with a volume Bragg grating output coupler

A diode end-pumped Nd:YAG microlaser passively Q-switched by Cr(4+):YAG with performances controlled by a volume Bragg grating (VBG) output coupler has been developed. Compared with operation at room temperature, the Q-switched laser pulse energy was increased, by a factor of 2 or more, by elevating the Nd:YAG temperature and locking the wavelength of emission with the VBG. Furthermore, the emission wavelength was tuned over 0.7 nm bandwidth by changing the VBG temperature while maintaining laser pulses of millijoule-level energy and short (less than 4 ns) duration.