CHOLESTERIC LIQUID-CRYSTAL BASED MULTILAYER OPTICAL STORAGE TECHNOLOGY

A novel approach to optical storage based on layering of cholesteric l iquid crystal (CLC) media has been proposed. CLC media have been chose n due to their unique property of selective reflection, wherein a CLC film reflects light of its characteristic wavelength and polarization handedness at near-zero loss while transmitting all other light. High contrast data patterns are created by selectively crosslinking 1 mu m size ''1'' and ''0'' data marks in the planar and the isotropic states , respectively. Recording ''1'' marks is accomplished by scanning a mo dulated UV laser beam over the CLC disk which is heated to 90 degrees C. The ''0'' marks are then crosslinked in the isotropic state. Up to 400 CLC layers can potentially be stacked on a single disk, which lead s ultimately to a single disk capacity of one terabyte. The novel conc ept has been demonstrated in a 6-layer experiment.