LASER MODE SELECTION IN MULTIARM GRAZING-INCIDENCE CAVITIES

A four-arm grazing-incidence cavity (GIC) is demonstrated. It ensures stable single-made operation in a pulsed laser system by interferometr ically enhancing mode selection; the corresponding standard GIC operat es on five modes. We show that the four-arm GIC gives the best overall performance in terms of mode selectivity and threshold when compared with the standard GIC or with three-arm GIC's. In addition, an analysi s of the interference effect is detailed that allows the four-arm GIC to be optimized for mode selection. Threshold gain and cavity losses a re calculated, and the predicted mode spacing and complex reflectance are experimentally verified. (C) 1998 Optical Society of America.