Abstract: 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.

Abstract: Ringing caused by acoustic resonances in an electro-optical crystal modulator and commencing at the trailing edge of a pulse may be suppressed by the combination of a second electro-optical crystal and a polarizer. The polarization of the ringing passing through the second crystal is rotated 90.degree. by applying an appropriate voltage to the second crystal at the trailing edge of the pulse. The polarizer, properly oriented, then blocks the ringing. The crystals may comprise such materials as Cadmium Telluride or Gallium Arsenide.

Abstract: In a laser system, the method of operating a laser simultaneously as an oscillator to produce a beam of coherent light and as an amplifier for backscattered light from targets illuminated by the coherent light in such beam is disclosed.