Storage density of shift-multiplexed holographic memory

The storage density of shift-multiplexed holographic memory is calculated a nd compared with experimentally achieved densities by use of photorefractiv e and write-once materials. We consider holographic selectivity as well as the recording material's dynamic range (M/#) and required diffraction effic iencies in formulating the calculations of storage densities, thereby takin g into account all major factors limiting the raw storage density achievabl e with shift-multiplexed holographic storage systems. We show that the M/# is the key factor in limiting storage densities rather than the recording m aterial's thickness for organic materials in which the scatter is relativel y high. A storage density of 100 bits/mum(2) is experimentally demonstrated by use of a 1-mm-thick LiNbO3 crystal as the recording medium. (C) 2001 Op tical Society of America.