Acousto-optic modulation of multicomponent Ar laser radiation

Polarisation-independent acousto-optic diffraction, in which optical radiation propagates along the optic axis of a gyrotropic crystal and an acoustic wave travels along a tangent to 'inner' wave-vector surfaces of the crystal, is considered. This diffraction geometry is shown to be optimal for the modulation of multicomponent laser radiation. The results are given of theoretical and experimental investigations of acousto-optic diffraction of six-component Ar laser radiation in the blue–green part of the spectrum, propagating in a TeO₂ single crystal. The highest diffraction efficiency (90%) is reported for a transverse acoustic wave of 90 MHz frequency when the acoustic wavefront is tilted at an angle of ~1.2^o to the optic axis of the crystal. A method of 'angular correction' of the direction of propagation of the diffracted rays, which makes it possible to concentrate all the diffracted radiation in one spot, is proposed.