Single frequency CW and Q-switched operation of a diode-pumped Nd:YAG 1.3µm ring laser

The use of an acousto-optic modulator in a ring laser to enforce unidirectional and hence single-frequency operation has been extended to the 1.3µm lines in Nd:YAG. We have also been able to obtain stable simultaneous operation on a single frequency in each of the 1.319µm and 1.338µm transitions either CW or Q-switched. The mechanism behind this behaviour is described and implications for other laser systems are discussed. When operated single frequency, up to 155 mW of CW output is produced, and 30 pJ, 40 nsec Q-switched pulses have been obtained