A diode-laser-pumped Nd:YAG ring laser incorporating a rhomb-shaped acousto-optic modulator as its only optical component is reported. The acousto-optic modulator itself enforces unidirectional and hence single frequency operation and can also be used as a Q-switch. When pumped by a 500 mW diode array Q-switched pulse energies of 20-mu-J and 18 ns duration, corresponding to a peak power of approximately 1 kW, were obtained.