▎ 摘　　要

We report for the first time that a MoS2/graphene heterojunction can behave as a saturable absorber to realize 2 and 3 mu m passively Q-switched bulk lasers. This heterojunction is prepared through a facile hydrothermal method. For the 2 mu m laser, a stable pulse is obtained with a pulse duration of 473 ns, output power of 553 mW, pulse energy of 5.267 mu J and repetition rate of 105 kHz. For the 3 mu m laser, a pulse duration of 355 ns is observed with an average output power of 112 mW and pulse energy of 0.889 mu J. These results indicate the great potential of MoS2/graphene heterojunctions for realizing mid-infrared pulse lasers.