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.