An apparatus and method for maintaining a desired position of a collimated light beam are provided. An optical system includes one or more passive optical elements movably positioned in the beam path. Beam position is responsive to movement of at least one of the passive optical elements. The actual position of the beam is detected and compared with the desired beam position. An error signal is generated and the beam path is altered responsive to movement of one or more of the passive optical elements. In further aspects, beam shaping optics, such diffractive optics, are provided to shape the sensed beam portion. In still other aspects, thermal conditions of the laser may be monitored and a thermal map is provided to automatically compensate for estimated beam drift due to thermal conditions.