The Transfer of a Holographic Structure from Dihromated Gelatin Layers on a Polymethylmethacrylate Substrate

Gelatin as Photosensitive Material

“…Instead of the modulation of the intensity of UV radiation by a SI, we have here a variable layer tanning (Figure 1c), that modulates the destructive effect of short-wave UV radiation on gelatin in the upper layers. A significant decrease in the thickness of the DCG layer (Table 1, # 11, 12) [49,50] up to the values of the order of λ provides high values of the DE η1 that are close to the theoretical limit for thin holograms. In the case of ultra-thin DCG layer (T < 1 µm), for a sufficiently long UV irradiation time, gelatin-free "windows" appear.…”

“…Multiple repetition of the cycle "UV radiation -washing -air drying" for the layers with the thickness T < 3-6 µm leads to the same result. This fact allowed one to realize the effective transfer of holographic relief structures from the DCG layer onto a PMMA substrate [50]. In this case the sequential application of the DCG treatment and the resists processing are used ( nuclear physics and more.…”

Gelatin as a Photosensitive Material

“…Instead of the modulation of the intensity of UV radiation by a SI, we have here a variable layer tanning ( Figure 1 c), that modulates the destructive effect of short-wave UV radiation on gelatin in the upper layers. A significant decrease in the thickness of the DCG layer ( Table 1 , #11, 12) [ 51 , 52 ] up to the values of the order of λ provides high values of the DE that are close to the theoretical limit for thin holograms. In the case of ultra-thin DCG layer ( T < 1 µm), for a sufficiently long UV irradiation time, gelatin-free “windows” appear.…”

“…Table 1 presents the main parameters of the regular holographic structures on silver halide photoemulsions of different types and DCG layers, created in the laboratory, by the SWUV method [ 43 , 44 , 48 , 49 , 50 , 51 , 52 ].…”

“…According to the theory of light scattering on large-scale inhomogeneities in the Kirchhoff approximation, if the distribution of the relief height is described by the Gaussian function [ 53 ], the amplitude reflection coefficient of the non-scattered component is equal to: where k = 2π/λ is the wave number, λ is the wavelength of light, σ is standard deviation of the relief height and ψ is the slope angle of the beam. For transmission structures [ 52 ] at ψ = 90°, Formula (2) is converted to: where is the relative intensity of a zero-order beam as a percentage of the incident beam, n 0 is the mean refractive index of gelatin equal to 1.53 (for λ = 0.6328 µm). The small values of the relative intensity of the non-scattered component, for example, ≤ 0.1%, are achieved with values of the standard deviation of the surface relief height σ ≥ 0.5 µm.…”