Recording of Holograms

Volume-phase holography often makes use of the difiiision of unreacted monomer in a monomer/polymer mixture towards the exposed areas where monomer has been 

Alternatively, a mixture of two monomers, having different reactivities and yielding polymers with different refractive indices, may be used In a further refine- 

Other workers have reported on the use of urethane (meth)acrylates for the recording of holograms. In some cases, thermal postcuring of an epoxide was used for fixation. This work has been reviewed in Ref. 

Volume phase holography using photopolymers has been reported to provide the highest information density in man-made systems, especially if unit volume is considered instead of unit area (Fig. 12) 

Another interesting application of holographic recording is the faceted disc used in laser scanners for read-out of universal product codes such as the bar code on, for example grocery products 

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In diffraction-limited recording of hologram, the size of particle image in transverse pd and longitudinal di pi) directions is given by [5]... 

Fig. 7. a - absorption spectra of PQ (curve 1) and photopa-oduct (curve 2) in polymeric matrix, b - diagram to explain hologram construction process in polymeric medium with diffusion enhancement distribution of molecules of PQ (O) and photoproduct ( ) across the sample bulk in the initial state (1), after recording of hologram-grating (2), after warmup (3), after fixation (4). 

Kakichashvili, Sh.D. (1974). Method of Polarization Recording of Holograms. Kvantovaja Electron (Quant Electr.), vol.l, N 6, pp.1435-1441, (Russian). 

It is also feasible to measure both droplet size and velocity simultaneously with the holographic method. Such a measurement system has been developed by Murakami and Ishikawa. 65()l They used two pulse lasers of different wavelengths to record two holograms on two different films, separated by an appropriate time interval. The displacements of moving particles were measured on a superimposed picture of the two films to determine the velocities of the particles. 

Figure 5.23 Schematic of two-beam recording of a hologram and laser beam visualisation of image.

Figure 7. Light-in-flight recording of a set of spheres illuminated by a 3-ps laser pulse. The light source (A) and the point of observation at the hologram plate (B) were close together and far from the object. Thus, the intersecting ellipsoidal light slice can be approximated into a spheroidal light slice with a large radius and a thickness of 0.5 mm.

Photochromic films of this type are suitable for recording polarization holograms because of the Veigert effect and oriented photodichroism.63... 

Figure 2. Recording and readout of hologram gratings, (a) During recording two plane waves interfere to produce sinusoidal interference fringes with period A. (b) During readout one incident plane wave produces various diffracted plane waves.

Figure 7. Holographic optical scanner, (a) A series of holograms is recorded in the coating on the inside of the glass ring, (b) In use, a hologram focuses an illuminating beam on the object to be scanned. As the ring is rotated, the hologram causes the focused beam to scan across the object. (See ref. 11 for further details.)...

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