Volume hologram

Fig. 6. Volume hologram recording where (a) is the transmission, and (b) the reflection.

Because the losses tend to be excessive in volume absorption gratings, volume holograms are realized in most cases using index (phase) gratings. 

Dichromated gelatin. This material is particularly sensitive to light in the blue and UV regions, but not the red. They are used to produce volume holograms that approach the theoretical limit in diffraction efficiencies. 

Photoreduction of Eosin, Erythrosin, and Rose Bengal with amines has been employed for a number of years to initiate polymerization of monomers in the absence of solvent. Examples of recent applications include the production of volume holograms [181], color images on plain paper [182], printing plates [183-185], and, in the presence of suitable peroxides, manufacture of coatings for glass fibers [186]. 

Electron transfer to the xanthenes, particularly reduction with amines, has been used for a number of years to initiate acrylate polymerization. A typical system is that reported to form volume holograms—lithium or zinc acrylate, triethanolamine and Eosin, Erythrosin, or Rose Bengal [290], Similar mixtures are used to form printing plates photoreducible dye, phenylac-ridine, and acrylate monomer [292], A recent patent application discloses aryl iodonium salts, Rose Bengal, and oxidizable triazines such as 2-methyl-4,6-bis(trichloromethyl)-s-triazine to polymerize acrylates [292],... 

Volume holograms have been produced using MB/TEOA coin-initiated polymerization of acrylamide (90). These compositions have successfully recorded and reproduced digital information from laser output, but at a low signal to noise ratio (14 dB). The scattering efficiency was, however, quite high for these systems (-65%) and the resolution obtained was near 1500 lines/ mm (90). 

Spiropyrans show promise for optical recording, three-dimensional optical memories,214 and holography.215 The dyes currently under study for these applications very probably will not be used merely dissolved in a bulk polymer matrix, but will be oriented in films and membranes, or adsorbed or vapor deposited on solid substrates to take advantage of the nonlinear optical properties of the colored forms. For example, thick (0.5 mm) PMMA films of 6-nitro-thiaBIPS can be used to record wavelength-multiplexed volume holograms with an infrared diode laser. This system is impractical at present because of fatigue and poor diffraction efficiencies.216... 

These photopolymer systems were found to contain both volume refractive-index modulation and thickness modulation the latter constitutes a thin hologram. The volume hologram was shown to be present by removing one glass cover and covering the surface with the same monomer mixture. Upon uniform overall exposure, the... 

Light-Sensitive Media-Composites for Recording Volume Holograms Based on Porous... 

Light-sensitive media for volume hologram recording Basic requirements and principles of design... 

The interest to static volume holograms with thickness of several millimeters is due, mainly, to their use in research and in creation of holographic optical elements (HOE) of various purposes with unique parameters (Sukhanov et al., 1984 Ludman at al., 1997 Popov, et al., 2000 Luo, at al., 2008). Requirements to materials for recording of such holograms are rather specific and cannot be met when using traditional light-sensitive materials. 

Recording media for construction of static 3D-volume holograms should have the following properties ... 

Specifics of parameter measurements of high-seiectivity volume holograms... 

Gulanyan, E.K., Dorosh, I.R., Iskin, V.D., Mikaelyan, A.L., Maiorchuk, M.A. (1979). Nondestructive readout of holograms in iron-dop>ed lithium niobate crystals. Soviet Journal of Quantum Electronics, Vol. 9, No. 5, pp.647-649 KiUich, H.C. (1987). A new ap>proach to read volume holograms at different wavelengths. 

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