▎ 摘　　要

Liquid saturable absorbers have some advantages in some aspects over solid saturable absorbers. In this paper, graphene oxide in heavy water (deuteroxide, D2O) dispersion was fabricated and used as absorber in Q-switched Nd:YAG laser for the first time, to the best of our knowledge. The shortest pulse width of the Q-switched laser is 523 ns, corresponding to a repetition rate of 92.9 kHz. The maximum peak power of Q-switched pulse is 6.6 W. Such a liquid absorber has the virtues of good optical transparency, high heat dissipation, and no contact damage.