Use of polarization sensitivity for three-dimensional optical data storage in polymer dispersed liquid crystals under two-photon illumination

We report on the use of the polarization-dependent fluorescence property in photorefractive polymer dispersed liquid crystals for three-dimensional (3D) optical data storage under two-photon absorption. The liquid crystals, which have optical anisotropy, exhibit an alignment-based fluorescence feature that depends on the polarization state of an excitation field. Such a polarization sensitivity can be confined to the small focal region under two-photon excitation, allowing the stable recording of a 3D bit array. A 3D data density of 204.8 Gbits/cm3 is achieved using ultrashort pulsed illumination at a wavelength of 900 nm. It is also demonstrated that the recorded data can be erased in bulk or as single bits and then rerecorded.