A two-mirror laser beam expander can be used to provide small amounts of beam steering by moving one mirror. Such a motion would generally introduce aberrations into the output wavefront that would restrict the amount of diffraction-limited beam steering achievable to very small amounts. This paper describes how some or all of the third-order aberrations introduced by moving one mirror can be eliminated. By proper design, substantial amounts of diffraction-limited beam steering can be achieved.
© 1978 Optical Society of America
David R. Shafer, "Laser beam steerer—expander," Appl. Opt. 17, 3584-3584 (1978)