Beam pointing switch

摘要

An optical beam switch is disclosed for sequentially pointing a laser beam to a plurality of terrestrial target locations at predetermined depression angles and at angular positions relative to a reference direction. The switch includes a CW laser whose collimated output beam is directed into a rotating retroreflector. The moving beam reflected therefrom describes a continuous circular path across the upper surface of a beam deflection device. The beam deflection device comprises a plurality of beam refracting prisms. The index of refraction and angulation of each prism determines the depression angle and azimuthal angle of the deflected beam. The depression angle is held precisely constant as the incident beam describes its arcuate path across the upper surface of the prism. The retroreflector may comprise three mutually-perpendicular mirrors, joined at a vertex, for providing a reflected beam parallel to and displaced from the incident beam. Alternatively, the retroreflector may comprise a triple mirror prism.