Three-Dimensional Information Storage in Alkali Halides by Two-Photon Absorption

摘要

Color centers can be produced in alkali halide crystals by two-photon absorption from an ultraviolet laser beam. Because the two-photon effect is a quadratic function of power density, a colored spot can be produced anywhere in the crystal by a sharply focused beam. This provides a means of storing binary information, which can be read by measuring the interaction of a focused laser beam with the color centers. A storage capacity of 5 x 10 to the 10th power bits/cc and reading and writing rates of 40 MHz are estimated for KBr. (Author)