Holograms, recording

Figure 6. (Left) Schematic showing basic TEM configuration for off-axis electron holography and (b) photograph showing electron microscope suitably equipped for recording holograms of magnetic materials.

Polymers with photochromic phenoxynaphthacenequinone side groups were also used for recording holograms.49... 

The Battelle group found that photoisomerization of various indigo derivatives could be used to record holograms which had low (<0.2%) scattering efficiencies (36). Their refractive-index data yield nQ = 2.9 x 10 cm for an N,N -dibenzoylindigo derivative. These systems were reversible. The quantum yields of isomerization were much lower in poly(methyl methacrylate) or polystyrene than in fluid solution, in accord with arguments presented earlier. Concentration quenching was also observed in solution. 

Fig. 12.4 Schematic depiction of a set-up for recording holograms. SLM Spatial light modulator.

Study of volume light-sensitive media using recorded holograms... 

As a test object, we used hologram-gratings, which were theoretically analyzed with the help of coupled wave theory (Kogelnik, 1969). This theory is an indispensable tool in study of RM using recorded holograms, as it allows relating the measured hologram parameters with the amplitude of modulation of optical characteristics of a medium. 

The performed experiments have shown the quality of constructed holograms to be strongly affected by physical and mechanical properties of samples, which are determined by their hardness, and the most important holographic characteristic, determined by synthesis conditions for medium samples, to be the dependence of diffraction efficiency, of recorded holograms on post-exposure warm-up time. The data given on Fig. 8a, curve 1, show a typical dependence, which is specific for optimal synthesis conditions and can be approximated with two straight lines, as shown on the figure (dashed line). 

Fig. 8. a - dependence of diffraction efficiency t of holograms, recorded on samples of different synthesis, on post-exposure warm-up time (tch is characteristic warm-up time) curve 1 - optimal synthesis, curve 2 - soft synthesis, curve 3 - hard synthesis, spatial frequency of hologram 640 mm-i. b - dependences of relative hardness index Kh of samples (curve 1), deviations of synthesis temperature from the given one AT (curve 2), latent image hologram DE (curve 3) on characteristic warm-up time tch of recorded holograms. 

Fig. 16. The diffraction efficiency kinetics curves comparison of different kinds of polarization recording holograms in Fulgide/PMMA film written by Gaussian beams (a) Experimentally measured results (b) Theoretically calculated results...

Fig. 25. The reconstructed images of parallel linear polarized transmission hologram and reflection hologram (a) reconstructed image of transmission recording hologram (b) reconstructed image of reflection recording hologram...

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