Microholographic data storage

In this paper, conventional page-oriented holographic storage requires a special setup starting with a spatial light modulator converting the incoming data stream into arrays of dark and bright pixels each representing a bit. Coherent light from a laser illuminates this page composer and interferes with a reference beam from the same laser in the photosensitive medium. Microholographic data storage /2/ has been suggested therefore to combine the holographic potential of high capacity with the mature compact disc and DVD technology. A microholographic write-system uses two counterpropagating strongly focussed laser beams generating a microscopic reflection grating in a photopolymer disc. Phase-conjugation may be useful to eliminate distortions occuring when a laser beam is focussed through upper grating layers to read a layer deeper inside the volume