Abstract: The output power of any laser is optimized by providing an output mirror with a transmission which varies as a function of position on the mirror and transmitted wavelength. The transmission which corresponds to the optimum output for a given laser wavelength is chosen by monitoring laser output and moving the output mirror in at least one direction essentially perpendicular to the laser beam axis while maintaining the orientation of its reflecting surface perpendicular to the laser beam axis, and locating the mirror position corresponding to optimum laser output.