Coherent summation of injection-locked, diode-pumped Nd:YAG ring lasers

A binary grating has been used to achieve coherent summation of diode-laser-pumped Nd:YAG ring lasers operating at 1.06 micron. Mutual coherence of two such devices was achieved by optical injection locking. This is believed to be the first demonstration of cw injection locking of solid-state lasers other than semiconductor diode lasers. By combining two beams, an efficiency of 75 percent (92 percent of the theoretical limit) has been demonstrated in a configuration that could be used to combine a large number of individual lasers.