1 Fine-grain silver halide emulsion layers are widely used for holographic recording by counterpropagating continuous laser beams. In the case of recording with nanosecond pulse radiation in such layers [1,2], a substantial decrease (by a factor of up to 20) in the diffraction efficiency and light sensitivity is observed. The effect of lowering the speed of silver halide photosensitive materials at short high-intensity exposures (reciprocity failure) is known and it has been described in some works [3][4][5][6].As we showed earlier [7,8], one of the possibilities of enhancing the sensitivity of photographic materials to pulse radiation is increasing the silver halide grain size. However, the diffraction efficiency considerably declines in this case. The determination of the optimal grain size is a complicated problem, since the light sensitivity and the diffraction efficiency are related not only to the size of grains but also to their concentration, physicochemical properties, and exposure and chemical-processing conditions.Previously [8], this problem was studied with the use of special fractional layers prepared for the purpose from the "Kurchatov Institute" emulsion. Five fractions were isolated in which the average grain size varied from 50 to 25 nm; i.e., in the range covering the dimensions of grains of standard holographic materials at 5-10 nm intervals. As a result of this study, we revealed the following.(1) The character of latent image in silver halidebased holographic layers depends on the time characteristics of writing beam and is related to the grain size. 1 (2) The efficiency of holographic recording by radiation with a pulse duration of the order of 10 -8 s increases with an increase in the silver halide grain size.(3) Monodispersity requirements imposed on emulsions are less strict in the case of pulsed exposures as compared with recording by continuous light.Thus, the requirements for materials and chemicalprocessing conditions in pulse holographic recording differ from those in the case of recording with continuous radiation. On the preparation of initial light-sensitive systems and final holographic structure, there is a possibility of enhancing the efficiency of contradirectional recording by pulsed radiation, including that of nanosecond pulse duration.In order to optimize the size of grains, it is necessary first of all to have an emulsion synthesis process that allows the grain size to be finely controlled.In this work, we studied the feasibility of preparation of photographic emulsions with various grain sizes using the process for the manufacturing of photographic emulsions with relatively large grains (up to 50 nm) for holographic recording in cocurrent beams. EXPERIMENTALThe synthesis was conducted using the double-jet emulsification process. Solutions of silver nitrate and halide salts were automatically fed in portions to a gelatin solution. The size of portions was controlled by compressed-air pressure. The stirrer speed was 1000 rpm. The emulsification time of such an emulsion wa...
In the article are studied the peculiarities of the registration of the colored holograms with the radiation of the pulsed laser, caused by the dimensions of the monocrystals of the silver haloide in the holographical layer and by the simultaneous registration on two wavelengths. Parameters of the materials for the colored registration and possibility of the object color reconstruction via two wavelengths (red and green) registration are evaluated.1. Investigation of the influence of the dimensions of the stals of the silver haloide onto the holographical parameters of the photolayer under the exposure by nano-and microsecond pulses.One of the problems of the registration of the reflective holograms with the help of the radiation with the nanosecond pulse duration is the aggravation of the holographical parameters of the silver haloide materials, which provide high resolution: the diffraction efficiency is diminished up to 20 times in comparison with the continuous or microsecond radiation. It may be caused by the small dimensions of the monocrystals of the silver haloide in these layers. In this work we were studying the influence of these monocrystals dimensions onto the diffraction efficiency of the reflective holograms, registered under the exposure of the ruby laser with the pulse durations 30 ns and 300 ts. We were studying the photolayers with the dimensions of the monocrystals in the layer from 20 to 50 nm; with the one (single fraction) or two (two fraction) dominating dimensions. It was find out that in the case of microsecond exposure the diffraction efficiency grows with the monocrystals diminishing, while in the case of the nanosecond exposure there is the optimal dimension, depending of the silver concentration in the layer and of the photo -chemical processing conditions (see fig.l). Diffraction efficiency in the case of two fraction layer is higher than in the case of single fraction (table 1). Table 1. Diffraction efficiency of the single and two fraction layers.
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