BROAD-BAND ACOUSTOOPTIC DEFLECTORS USING SONIC GRATINGS FOR FIRST-ORDER BEAM STEERING

A broad-band acousto-optic (AO) Bragg deflector using acoustic beam steering to track the Bragg angle is described. The variable acoustic beam is the ″first order″ output of a flat transducer grating made up from a single piezoelectric platelet. The correct diffraction theory applicable to AO deflectors is reviewed, including an accurate analytical description of the intensity of the second-order light that limits the deflector's bandwidth, and the theory of broad-band steering deflectors is developed. Techniques are presented to improve the fabrication yield of devices using lead molybdate as the AO medium, and to easily convert any standard deflector to the beam-steering mode of operation.