Abstract: A crystal modulator (20) is on an axis (19) which is positioned in translation and pivotal rotation with respect to another axis (17) of a laser. The crystal modulator (20) is supported in an inner housing (18) on axis (19). The inner housing is supported within an outer housing (16) which is affixed to the laser. Mating surfaces (32, 38) on the inner and outer housings are spherically contoured so that the inner housing may be pivoted about the center (24) of the extended sphere of the mating surfaces and thereby pivot axis (19) into coincidence with axis (17). An end (22) of the crystal modulator is positioned at this spherical center. Of two sets of four setscrews (26, 28) threaded into the outer housing, one set is disposed to contact the inner housing directly. The other set of screws is disposed to contact a ring (36) whose inner surface comprises one of the spherical surfaces.