Optimized spatial frequency response in silver halide sensitized gelatin

Abstract

Silver halide sensitized gelatin processing is optimized to increase the spatial frequency response in Agfa-Geυaert 8E75 HD emulsion; therefore a diffraction efficiency of 55% in reflection gratings of 5000 lines / mm is achieved.

Holographic 4x4 star coupler fabricated in silver-halide sensitized gelatin

“…An interesting observation reported in [6] is that the diffraction efficiency reached its maximum and remained constant with increased exposure, and only the stain increased. This contradicts the experiments in [7][8][9][10] where a relative slow fall towards higher exposures was observed. We observed an even stronger dependence on the exposure energy, as seen in Fig.…”

“…According to [8,9], the final efficiency strongly depends on the concentration ratio between the Cr and Br ions in the bleach bath. In [10], the authors have reported that eliminating the potassium bromide from the bleach had decreased the efficiency significantly. They believe that the potassium bromide controls the life span of the Cr ions and, hence, the diffraction efficiency.…”

“…It can operate in a large window of replay wavelength only by adjusting the corresponding Bragg angles. optimized for efficiency and spatial frequency response in their later works [8][9][10]. This is apparently due to the extreme high degree of hardening of the gelatin in Agfa plates.…”

“…[8], the maximum diffraction efficiency we achieved was about 50%. The aim of our formula is to provide an alternative rather than to challenge the results in [7][8][9][10]. We solved the problem of the high initial hardening by soaking the plates after fixing in hot water, t= 75°C, for 10 mm.…”

Silver halide sensitized gelatin derived from BB-640 holographic emulsion

“…The spatial-frequency response for SHSG holograms recorded in BB-640 plates is better than for Agfa 8E75 HD plates, since with the latter plates the diffraction efficiency falls rapidly when the spatial frequency is increased. 30 This rapid decrease in the diffraction efficiency observed with Agfa plates occurs because the grains are larger 31 than those of BB-640 plates, as we indicated in Subsection 2.B.…”