A review of electro-optic beam deflection techniques

Abstract

Electro-optic beam deflectors are of two basic types. The digital beam deflector produces a range of quantized beam output positions by the use of an assembly of electro-optic polarization switches coupled through birefringent elements. The analogue light deflector produces continuously variable range of beam output positions by electro-optic variation of the refractive index of a deflecting element. In each case the number of resolvable output positions is determined by the diffraction angle of the light beam, the amount of background light generated, and the aberrations of the system.Electro-optic beam deflectors may in future be applied to data reading and storage in computers, as well as in information displays, optical printers, and in multiple switching arrays. Using the electro-optic materials at present available, the maximum number of resolvable output positions in a two-dimensional deflector system is of the order of 106/cm2. Limitations of switching speed arise through power dissipation in the electro-optic material and the large reactive energy storage in the switches. However, using existing materials and those which should be available in the near future, switching speeds in excess of 106 random addresses per second should be possible in deflectors of this capacity.