Theory of holograms formed using a coded reference beam

Holographic Data Storage Systems

“…In contrast to angular multiplexing, the grating vector spectra for each hologram overlap; what distinguished each hologram are the phase relationships among the recorded holograms. Krile et al [39], [40] and Morozov [41] have independently outlined this procedure for thin holograms, for which there is no Bragg selectivity. Because of its simplicity, we examine this procedure to illustrate basic properties of phase encoding.…”

“…In general, the details of the crosstalk will depend on the details of the speckle pattern and the architecture of the HDSS. We can refer to (41) to estimate the upper bound of SNR. In particular, (41) shows that crosstalk decreases as the number of resolvable reference beam wave vectors in the dimension associated with the speckle pattern increases.…”

“…We can refer to (41) to estimate the upper bound of SNR. In particular, (41) shows that crosstalk decreases as the number of resolvable reference beam wave vectors in the dimension associated with the speckle pattern increases. For speckle multiplexing geometries, is given by (45) By engineering the magnitude and the correlation function of the phase mask, the decorrelation distance is modified.…”

Overloaded phase-code multiplexing for volume holographic storage

“…So far several implementation concepts of phase-code multiplexing have been discussed. Owing to its straightforward implementation a popular method has been random phase encoding, which utilizes random phase distributions in the reference wave (e.g., [7]). It can be realized by means of a collimated laser beam that illuminates a (1-D) random phase plate in the reference arm.…”

Holographic random access memory (HRAM)

“…When the hologram is subsequently illuminated with one of the original reference beams, light is diffracted from the grating in such a way that the signal beam is reproduced. Many holograms can be multiplexed within the same volume of the material by angle [6], [7], fractal [8], wavelength [9], [10], phase code [11]- [13], peristrophic [14], and shift [15], [16] multiplexings.…”