VOLUME HOLOGRAPHIC STORAGE IN HYDROGEN TREATED GERMANO-SILICATE GLASS

Strong permanent gratings (index change Delta n similar to 3 X 10(-3)) have been formed in bulk hydrogen treated germane-silicate glass with 242 nm exposure. Diffraction efficiencies of 6% and initial sensitivity (Delta n/incident energy density) of 2 X 10(-5) cm(2)/J have been obtained. The observed sensitivity is comparable to the values achieved in other holographic storage materials such as LiNbO3. It is estimated that by more uniform hydrogen loading of the sample, diffraction efficiencies of 100% can be obtained in 3 mol % GeO2 samples of only 175 mu m thickness. These materials are potentially useful as fast access time (sub-mu s), high capacity (similar to 0.8 Tbits), robust, inexpensive write-one-read-many storage media, narrow (subangstrom) linewidth optical filters, and other optical components.