A LD end-pumped Nd:YAG,all-solid-state ultraviolet laser is demonstrated under acousto-optic Q-switch operation,by using a simple and compact flat-flat cavity resonator,with type Ⅰ phase-match LiB3O5(LBO) as secong harmonic generation crystal and type Ⅱ phase-matched LBO as third harmonic generation crystal.With an input pump power of 28 W,average power of 8.1 W at 1 064 nm was generated with the repetition rate 10 kHz.Using the extra-cavity frequency conversion of critical phase match LBO cryst...