Three-dimensional optical memory

Abstract

Selected domains, normally 10.sup.3 .times.10.sup.3 such domains arrayed in a plane, within a three-dimensional (3-D) volume of active medium, typically 1 cm.sup.3 of spirobenzopyran containing 10.sup.2 such planes, are temporally and spatially simultaneously illuminated by two radiation beams, normally laser light beams in various combinations of wavelengths 532nm and 1024nm, in order, dependent upon the particular combination of illuminating light, to either write binary data to, or read binary data from, the selected domains by process of two-photon (2-P) absorption. One laser light beam is preferably directed to illuminate all domains of the selected plane in and by a one-dimensional spatial light modular (1-D SLM). The other laser light beam is first spatially encoded with binary information by 2-D SLM, and is then also directed to illuminate the domains of the selected plane. Direction of the binary-amplitude-encoded spatially-encoded light beam is preferably by focusing, preferably in and by a holographic dynamic focusing lens (HDFL). During writing the selected, simultaneously illuminated, domains change their isomeric molecular form by process of 2-P absorption. During reading the selected domains fluoresce dependent upon their individually pre-established, written, states. The domains' fluorescence is focused by the HDFL, and by other optical elements including a polarizer and polarizing beam splitter, to a 10.sup.3 .times.10.sup.3 detector array. I/O bandwidth to each cm.sup.3 of active medium is on the order of 1 Gbit/sec to 1 Tbit/sec.