Passively Q-switched Single-longitudinal-mode c-cut Nd:GdVO4 laser with a twisted-mode cavity

Single-longitudinal-mode operation is achieved in a twisted-mode-cavity c-cut Nd:GdVO4 laser. With a semiconductor saturable absorption mirror as an intracavity saturable absorber to launch passive Q-switching, no mode-locked spikes are observed on the temporal envelopes of the Q-switched output pulses due to the complete elimination of spatial hole burning in the gain medium to suppress longitudinal multi-modes. The maximal average output power is 1.24 W with the repetition rate of 76.3 kHz, and the single pulse energy is 16.0 μJ. The pulse width and polarization ratio of the output laser beam are measured about 150 ns and 53:1, respectively.