A cw CO2laser operating on theR(30) 9‐&mgr;m transition is down shifted by 180 MHz in a pair of acousto‐optic modulators, and used to optically pumpsR(5,0) transition of NH3at line center. Vibrational inversion is created in the &ngr;2mode, and cw oscillation is observed on 20 different NH3lines, spanning the region between 10.7 and 13.3 &mgr;m. Single line output powers as high as 760 mW were measured in a waveguide cavity. The operation of this laser is explained using a simple thermalization model, and several potential applications are discussed.