Some Aspects of a Large Capacity Holographic Memory

Abstract

Specifications of a holographic memory suitable for a capacity of 10(8) bit are presented. Mathematical calculations show the influence of various system parameters. The storage density is derived as a function of the maximum spatial frequency in the storage material, the aspect ratio of the data input mask, and the crosstalk. In addition, optimizations of the storage density and the optical efficiency of the system are discussed.

<title>Holographic memory with speckle-wave volume hologram</title>

“…In the same way the SNR value for angular multiplexed holograms with speckle angular selectivity can be presented as: SNR = N ID(m) (9) exp[(p6OA _ AO)2]…”

Cascaded Phase Fourier Holograms

“…Corresponding intensity distributions are shown in figure 11 . Because of the randomness of 0(1, m) [16], the second term in equation (1) (2) in the hologram area, and to =exp (Apo ) elsewhere . The value of the constant phase shift measured in the experiment is b=hDo +hy log E0 , and tp o is the phase shift of light which passes through the unexposed but bleached emulsions, h=D(p/OD is a linear coefficient representing the ratio between the phase shift of the light in a bleached emulsion and the change in the optical density of the emulsion brought about by bleaching, Do is a mean optical density, y is the slope of the linear part of the HaD curve, Eo is a mean exposure and I is the intensity normalized in such a way that the intensity of the reference wave Iref=B 2 =1 The complex amplitude transmittance given by equation (2) can be expressed as [13] to =exp (i')IZ, (3) where z=ihy/ln 10 .…”

Fabrication of Modified Random Phase Masks with Phase Modulation Elements Exhibiting Gaussian Profiles Using Molecular Migration under Photopolymerization

“…This trend is inevitably linked to a requirement of increased storage capacity for memory devices. Hologram memory is a promising candidate for this purpose because of the use of parallel data processing for recording and the reconstruction of page data at high densities [1][2][3]. Therefore, numerous related technologies have been studied for optical systems, including recording media [4][5][6][7][8][9][10][11][12][13].…”