Graphene Q-switched Tb:LiYF₄ green laser

We report the Q-switched operation of a Tb³⁺-laser for the first time, to the best of our knowledge. The passiveQ-switching was realized by a 15% Tb:LiYF₄ gain medium and a single-layer graphene saturable absorber. An average output power of 744 mW at 544 nm was achieved with slope efficiency of 41%, pulse width of 2.9 µs, and repetition rate of 38.7 kHz. The corresponding pulse energy and peak power were calculated to be 19.2 µJ and 6.6 W, respectively.