Polarization-multiplexed optical memory with urethane-urea copolymers

We present a polarization-multiplexed optical memory with urethane-urea copolymers. The side chains of the urethane-urea copolymers induce cis-trans isomerization by illumination of blue or green light, and they align perpendicular to the linear polarization of the illuminated light, thus producing optical anisotropy. We found that the material showed selective anisotropy for the particular direction that was perpendicular to that of the recording beam polarization. By use of the anisotropic property three different data pages were multiplexed at the same spot of the medium. Erasure of the recorded bit data is also demonstrated.