Abstract

We report the existence of a room temperature hologram fixing process in certain Bi₁₂SiO₂ (BSO) crystals, which appears to be due to the formation of a complementary grating of positive charges that compensates the photo-induced electronic space-charge field^(1,2). Uniform illumination of the crystal with green light, in presence of an external D.C. electric field, erases the deep-level electronic charge pattern and reveals the positive charge grating which then decays with its own characteristic decay time. We believe, in agreement with the work of Strohkendl⁽³⁾, that the hole charge pattern involves shallow traps. Since these traps can be thermally activated, the decay time constant can be further increased significantly by lowering the crystal temperature.

© 1990 Optical Society of America