We report the performance of an optically pumped submillimeter wave laser incorporating a Michelson interferometric output coupler consisting of three mirrors and a metal mesh beam splitter. 10.33-μm radiation from a pulsed CO2TEA laser was used to pump NH3for generating submillimeter wave radiation at 281 μm. Optimum output was achieved by coupling out 59 percent of the radiation per pass using a 250-lines-per-inch mesh at a phase angle of 49°. The submillimeter laser operated in the TEM00mode and was tunable over its free spectral range of about 350 MHz. Translation of the coupling mirror allowed optimization of laser output.