provides the aspect ratio and the absolute orientation of the pair determines the orientation of the spot axis if the expansion m of the two expanders is equal and the expansion axes are crossed at 90 degrees then a symmetric expansion and a round beam with expansion m is achieved if the expansion axes coincide then an expansion m 2 is along only one axis and the aspect ratio of the beam is modified by a factor of m 2 it is preferred that beam deviation be controlled so that device rotation does not cause spot position errors or beam clipping two element cylindrical beam expanders and anamorphic prisms as described in u s pat no 6 219 169 and shown in fig8 have no capability to correct the wedge element errors in the non expanding axis that will cause beam steering high accuracy elements are therefore preferred for precision applications desensitized and or adjustable compensated devices can also facilitate higher precision those skilled in the art of optical design and computer modeling will be able to assess the precision requirements for specific requirement of spot placement beam expanders with one reflective surface can provide beam steering capability to facilitate alignment by mechanical adjustment for tilt desensitization a second reflective surface can be provided to minimize beam steering effects when the maximum expansion is chosen to be greater than required.