HIGH-POWER SINGLE-FREQUENCY LASERS USING THIN METAL FILM MODE-SELECTION FILTERS

In this paper we present the theory of mode selection by use of a thin metal film in the laser cavity and we derive formulae both by a rigorous method and by using a lumped‐circuit approach. Experiments performed with a 500‐mW argon ion laser showed that 350 mW or 70 percent of the multimode power could be obtained in single‐frequency operation using this technique. Somewhat lower efficiencies were obtained with a neodymium‐doped yttrium aluminum garnet laser. We compare this with other mode‐selection techniques. © 1969 The Bell System Technical Journal