DATA READING IN 3-DIMENSIONAL OPTICAL-MEMORY DEVICES BASED ON PHOTOCHROMIC MATERIALS WITH THE USE OF LASER-INDUCED FLUORESCENCE AND COHERENT 4-WAVE-MIXING

The problem of nondestructive reading of the data stored in the bulk o f a photochromic sample is analyzed We propose a model for the descrip tion of data reading in photochromic molecules by means of one-and two -photon luminescence. Along with photochromic transitions, the propose d model takes into account variation in the populations of molecular l evels under the action of pumping radiation. This model provides an op portunity to satisfactorily reproduce the kinetics of the decay of the colored form in three-dimensional spiropyran samples. We investigate linear and nonlinear optical properties of indoline spiropyrans and an alyze the efficiency of using such materials for implementing three-di mensional optical-memory devices. The possibilities of data-reading me thods with the use of fluorescence and four-photon techniques are comp ared.