Controlled transparencies based on magnetic crystals

A study was made of the possibility of using magnetooptic materials (single-crystal orthoferrite plates cut normally to the optic axis and epitaxial bismuth-substituted garnet films) as media in controlled transparencies (page composers). Such use was based on the magnetooptic characteristics and technologically induced hysteresis of these materials. An investigation was made of the optical parameters, required control power, and dynamic properties. An optical contrast exceeding 350:1 and a total optical efficiency > 10% were achieved. The switching current was less than 1 A. The switching time of a transparency element depended on the material used and control current, and was within the range 10^–6–10^–8 sec.