Three-dimensional patterned media for ultrahigh-density optical memory

Abstract

We report a recording medium in which a three-dimensional nanoscale structure can be photofabricated for multilayered optical memory using a two-photon process. By fabricating the structures in the medium, we can control the shape of recorded bits and, in effect, their spatial frequency distribution. We succeeded in recording bits with a $0.5\mu \mathrm{m}$ interval in any particular plane and $2.0\mu \mathrm{m}$ interval between successive layers. Thus, storage density of $2.0\mathrm{Tbits}∕{\mathrm{cm}}^3$ is achieved.