Reflective Relay Optics for Use in Laser Deflection Systems

The optical coupling between the two axes of a light beam deflector may be conviently accomplished by using a reflective relay optical system. Such a system is generally less lossy, less costly, and easier to align than its refractive counterpart. The principal disadvantage is that since it is necessary to operate the relay off-axis, there is an interaction introduced between the otherwise orthogonal scan axes. This interaction may be eliminated electronically, however, by applying an appropriate coupling network between the deflection amplifiers. A breadboard prototype of such a reflective relay system has been operated and found to be capable of resolution of greater than 1000 resolvable elements per axis (with 2-mm aperture) and accuracy of greater than 0.5%.