Unidirectional diode-laser-pumped Nd:YAG ring laser with a small magnetic field

Single-mode operation of a monolithic semiconductor-laser-pumped unidirectional ring Nd:YAG laser has been demonstrated at 1319 and 1338 nm. The ring design optimizes the polarization eigenvalue difference between counterpropagating modes of the ring. The laser threshold is 4.5 mW, and the magnetic-field requirement for unidirectional operation is approximately 100 G.