Real-time holography

Photorefractive polymers are also being developed for use in both permanent and real-time holography (see section 5.6.3). 

Potential applications of photorefractive materials are manifold. To date, demonstrated effects include real time holography, correlation filtering, and various "novelty filter applications, one of which is the development of a microscope which distinguishes moving objects (such as living cells) from a stationary background.(149) The latter application employed BaTiC>3 as the active material. 

Birabassov R, et al. 1998. Thick dye doped poly (methyl methacrylate) films for real time holography. Appl Opt 37(35) 8264 8269. 

Chen, A. G. Brady, D. J. Real-time holography in azo-dye-doped liquid crystals. Opt. Lett. 1992,17, 441 43. 

See, for example, B. Fischer, M. Cronin-Golomb, J. O. White, and A. Yariv, Amplified reflection, transmission and self-oscillation in real-time holography, Opt. Lett., vol. 6, pp. 519-521, and references therein. 

Photoinduced conformational changes in azo-dye-doped liquid crystals have been used for real-time holography [65]. The orientation of azo dyes by an optical field, the Weigert effect [66], has been used to induce orientation of liquid crystals both in the bulk and in alignment layers [67, 68]. 

Ferroelectric liquid crystals are becoming increasingly promising for SHG devices and Pockels modulators [117]. The second harmonic intensity may be modulated [118]. A review of advanced liquid crystal polymers is given in Dubois [119]. Potential applications also include phase conjugation and real-time holography. 

Gruneisen, M. T., and J. M. Wilkes. 1997. Compensated imaging by real-time holography with optically addressed spatial light modulators. In Spatial Light Modulators. G. B. Bmdge and S. C. Esener (eds.). OSA TOPS Vol. 14. 

The purple membrane is harvested semiindustrially from halobacteria mutants which are bred in fermenters. The BR is then embedded into a polymeric matrix of poly(vinyl alcohol) or polyacrylamide. The BR films manufactured in this way are used for different applications, preferably in holography, for example, as a reversible transient data storage system for optical information processing (159). Another example is real-time interferometry by using the property of BR films to integrate over time (160). BR has been proposed also as a two-photon memory material because of its unusually large two-photon cross section. 

From the optical standpoint the outstanding properties of dynamic scattering are that it can be electrically controlled in two dimensions and the active motion of the scattering centers. By utilizing the property that dynamic scattering can be electrically controlled, it is possible to build electrooptic devices with transmission characteristics that can be controlled in two dimensions and as a function of time. Such devices can lead to new real time techniques in ultrasonic and microwave holography and in coherent optics data processing. 

Photorefractivity Real-time recording of optically encoded information, Holography... 

DFWM (Fisher 1983) is in fact a real-time variant of optical holography, which has been known since the sixties of the 19 century two laser beams (here, forward pump and object beam) are overlapped coherently imder a small angle 0. They induce in a nonlinear medium with susceptibility an interference pattern (grating), which contains information about the amplitude and phase relations between the contributing waves. This information is recovered via Bragg scattering using a third beam (backward pump) and gen-... 

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