A holographic plate, its preparation method and application

Abstract

This invention provides a holographic plate, its preparation method, and its application. The holographic plate comprises a substrate, a bottom layer, and a silver halide photosensitive layer. The silver halide photosensitive layer is adhered to the bottom layer via the bottom layer. Both the substrate and the bottom layer are hydrophilic. The silver halide photosensitive layer is formed from a transition metal-doped silver halide emulsion. This holographic plate exhibits ultra-high resolution, solves the high-illuminance reciprocity law failure problem, and improves the material's picosecond response to 355nm lasers. The resolution of this holographic plate at 355nm is higher than 2500 lp / mm.

Description

Technical Field

[0001] This invention relates to the field of laser holography. More specifically, it relates to a holographic plate, its preparation method, and its applications. Background Technology

[0002] Holography is a novel photographic technique that records all information about the amplitude and phase of the reflected waves from a photographed object. Ordinary photography records the light intensity distribution on the surface of an object, but it cannot record the phase information of the reflected light, thus losing its three-dimensional effect. Holography uses a laser as the illumination source, splitting the emitted light into two beams. One beam shines directly onto the photosensitive film, while the other beam, reflected by the object, shines onto a holographic plate. The two beams interfere with each other on the holographic plate, and the degree of light sensitivity at each point on the holographic plate varies not only with the intensity but also with the phase relationship between the two beams. Therefore, holography records not only the intensity of reflected light on the object but also its phase information. Optical holography is expected to find wide applications in stereoscopic films, television, exhibitions, microscopy, interferometry, projection lithography, underwater exploration, internal metal exploration, preservation of precious historical artifacts and works of art, information storage, remote sensing, and the study and recording of rapidly changing instantaneous phenomena and processes (such as explosions and combustion). Holographic plates are crucial for recording rapidly changing instantaneous phenomena, requiring rapid responses to nanoseconds or even picoseconds and high resolution to capture the instantaneous state of the illuminated object. Existing technologies include, for example, the ultraviolet I and II holographic plates from Tianjin Nuorexinda Technology Co., Ltd., which use very fine and uniform silver halide crystal particles with a photosensitive range of 2500 Å-5000 Å in the blue-ultraviolet region. Tianjin Weiyou Instrument Co., Ltd.'s silver halide holographic plates have a photosensitive wavelength of 632.8 nm and a resolution greater than or equal to 3000 lines / mm. The 11th Research Institute of the Ministry of Electronics Industry has disclosed an "ultra-fine particle" plate preparation process, using silver chloride-bromide mixed crystals to prepare the "ultra-fine particle" plate, with a resolution measured by laser interferometry as >3300 lines / mm. Shipley, Inc. of the United States produces photoresist-based recording materials suitable for the 441.6 nm wavelength of He-Cd lasers. The DMP series products developed by Polaroid in the United States are sensitive to blue (441.6nm), green (514.5nm), and red (632.8nm) light, respectively; while Slavich in Lithuania produces laser interference recording materials for 632.8nm and 532nm. However, none of the above holographic plates specify their resolution under picosecond laser exposure, let alone achieve a sub-nanosecond to picosecond response at 355nm. Therefore, providing a holographic plate with high resolution under picosecond laser exposure is of great significance. Summary of the Invention

[0003] The first objective of this invention is to provide a holographic plate that has high resolution, a 355nm sub-nanosecond to picosecond response, and when the holographic plate is used in the field of laser interferometric imaging, the resulting image has high resolution and high imaging density.

[0004] The second objective of this invention is to provide a method for preparing a holographic dry plate.

[0005] The third objective of this invention is to provide an application of a holographic dry plate.

[0006] To achieve the first objective mentioned above, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a holographic plate comprising a substrate, a bottom layer, and a silver halide photosensitive layer, wherein the silver halide photosensitive layer is adhered to the substrate via the bottom layer, and both the substrate and the bottom layer are hydrophilic; the silver halide photosensitive layer is formed by an emulsion of silver halide doped with transition metals.

[0008] The substrate supports the silver halide photosensitive layer. Furthermore, this invention discovers that the silver halide photosensitive layer formed by the silver halide emulsion doped with transition metals can utilize the transition metal doping into the silver halide lattice to form shallow electron traps of different energy levels. The synergistic effect with the silver halide improves the response sensitivity of the holographic plate to picoseconds.

[0009] Furthermore, the transition metal is selected from one or more of chromium, manganese, cobalt, nickel, copper, zinc, yttrium, zirconium, ruthenium, rhodium, palladium, cadmium, osmium, iridium, and platinum.

[0010] Preferably, the transition metal is selected from one or more of iridium, rhodium, and osmium. More preferably, the transition metal is iridium, rhodium, and osmium. These three transition metals can form traps at different energy levels in the silver halide lattice, resulting in a superior synergistic effect.

[0011] According to a specific embodiment of the present invention, the substrate is a glass sheet or film that has undergone hydrophilic treatment. The hydrophilic treatment can be performed by means of ultraviolet light or plasma treatment to enhance the hydrophilicity of its surface.

[0012] Furthermore, in the transition metal-doped silver halide emulsion, the molar ratio of the transition metal to silver halide is 10. -6 -10 -1 1. Preferably, in the transition metal-doped silver halide emulsion, the molar ratio of the transition metal to silver halide is 10:1. -6 -10 -3 :1.

[0013] Furthermore, the thickness of the silver halide photosensitive layer is 1-10 μm. If the thickness of the silver halide photosensitive layer exceeds this range, the resolution of the holographic plate will decrease.

[0014] Secondly, the present invention provides a method for preparing the above-mentioned holographic plate, comprising the following steps:

[0015] 1) Add silane coupling agent and film-hardening agent to gelatin aqueous solution, and then use extrusion coating method to uniformly coat one surface of the substrate to obtain the bottom layer that adheres to the substrate;

[0016] 2) Mix silver salt solution, chlorobromoiodine solution containing transition metal ions and gelatin solution containing surfactant to obtain a mixture, then carry out an emulsification reaction, and then let it stand at 0-4℃ to obtain crude latex.

[0017] 3) The crude latex is washed to remove impurities, and purified latex is obtained;

[0018] 4) The purified latex is chemically sensitized, and then a surfactant is added and coated onto the bottom layer surface that is adhered to the substrate to obtain the final product.

[0019] The microstructure of the silver halide photosensitive layer in the holographic plate prepared by the method is granular, with a particle size of 10-100 nm. If the particle size exceeds this range, the resolution of the holographic plate will decrease.

[0020] Furthermore, in the above method, in step 2), the mass concentration of the silver salt solution is 1%-20%.

[0021] In step 2), the molar ratio of chloride ions, bromide ions and iodide ions in the chlorobromoiodine solution containing transition metal ions is 20-80:15-55:5.

[0022] In step 2), the molar ratio of silver ions, transition metal ions, and bromide ions in the mixture is 1:10. -6 -10 -1 0.5-10.

[0023] In step 1), the amount of gelatin aqueous solution added is not particularly limited in principle in this invention. Those skilled in the art can select and adjust it according to the actual situation and the requirements of the holographic plate. In order to better ensure the mechanical properties of the holographic plate, the mass concentration of the gelatin aqueous solution is preferably 0.1%-10%.

[0024] In step 1), the amount of silane coupling agent added is not particularly limited in principle in this invention. Those skilled in the art can select and adjust it according to the actual situation and the requirements of the holographic plate. In order to better ensure the mechanical properties of the holographic plate, the preferred amount of silane coupling agent added is 0.01%-1% of the mass of the gelatin aqueous solution.

[0025] In step 1), the hardening agent is selected from ethylene or aldehyde compounds. In principle, the present invention does not impose any particular limitation on its amount; those skilled in the art can select and adjust it according to the actual situation and the requirements of the holographic plate. To better ensure the mechanical properties of the holographic plate, the present invention preferably uses an amount of hardening agent of 0.1%-10%.

[0026] In step 2) or step 4), the surfactant is a fluorocarbon surfactant, anionic surfactant, or nonionic surfactant. Preferably, the surfactant includes fluorocarbon 203, sodium diisooctyl succinate sulfonate, or polyvinylpyrrolidone.

[0027] In step 2), the emulsification reaction takes 0.5 min to 30 min.

[0028] Step 4) includes the following steps:

[0029] The pH of the purified latex is adjusted to 4-8, and then a chemical sensitizer is added, and the reaction is carried out at 40-60°C; wherein the chemical sensitizer is selected from one or more of Na2S2O3, HAuCl4 and NH4SCN.

[0030] Thirdly, the present invention provides an application of the above-mentioned holographic plate in the field of laser interferometric imaging.

[0031] Furthermore, unless otherwise specified, all raw materials used in this invention are commercially available. Any range described in this invention includes endpoints, any values ​​between endpoints, and any sub-ranges formed by endpoints or any values ​​between endpoints. Unless otherwise specified, all percentages are mass percentages, and all solutions are aqueous solutions.

[0032] The beneficial effects of this invention are as follows:

[0033] The photosensitive layer of the holographic plate provided by this invention is formed using a photosensitive emulsion doped with transition metal elements. This photosensitive layer improves the response sensitivity of the holographic plate to picosecond lasers, fully utilizes the synergistic effect of silver halide and transition metals, and enables the holographic plate to achieve outstanding imaging performance. It solves the problem of reciprocity law failure under high illumination and improves the material's response to 355nm laser picosecond lasers. The resolution reaches 2500 lp / mm in 355nm laser interferometric imaging.

[0034] The method for preparing holographic dry plates provided by this invention is simple, low-cost, and can be mass-produced, with broad application prospects. Attached Figure Description

[0035] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0036] Figure 1 The image shown is a scanning electron microscope (SEM) image of the transition metal-doped silver halide emulsion from Example 1.

[0037] Figure 2 The spectral range diagram of the holographic plate of Example 1 is shown.

[0038] Figure 3 The picosecond response curve of the holographic dry plate of Example 1 is shown.

[0039] Figure 4 A comparison graph showing the picosecond response curves of the holographic dry plate of Example 2 and Comparative Example 1 is presented. Detailed Implementation

[0040] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1

[0042] A holographic plate, the preparation method of which includes the following steps:

[0043] (a) Preparation of transition metal-doped silver halide emulsions

[0044] 1) Weigh 37.5g of AgNO3 and dissolve it in 220.5mL of deionized water to form a silver salt solution;

[0045] 2) Weigh 7.71g KBr, 9.41g NaCl, and 2.39g KI and dissolve them in 240mL deionized water to form a chlorobromoiodine solution. Then add 0.45mL of 10... -2 Potassium iridate at mol / L, 0.45 mL 10 -2 Potassium rhodium at mol / L and 0.45 mL of 10 -2 Potassium osmium tetroxide (mol / L) was used to prepare a chlorobromoiodine solution containing transition metals.

[0046] 3) Weigh 90g of gelatin and dissolve it in 1800mL of deionized water to form a gelatin solution. Add 13g of polyvinylpyrrolidone to the solution to obtain a gelatin solution containing a surfactant.

[0047] 4) Using a computationally controlled dual-injection emulsifier, the silver salt solution, the chlorobromoiodine solution containing transition metals, and the gelatin solution containing surfactant were added at a feeding rate of 88 mL / min. After mixing and reacting for 5 min, the product was bagged and frozen in a refrigerator (0-4℃) to obtain crude latex. After freezing, the emulsion was washed with 2.5% sodium sulfate solution to remove impurities such as salt, obtaining purified latex.

[0048] 5) Weigh 40g of purified latex, adjust the pH to 6.0 with 10% HAc, add 0.33mL of 0.1% sodium thiosulfate and 5.0mL of 0.0167% chloroauric acid, and perform chemical sensitization for 60min to obtain the final product.

[0049] (II) Preparation of Holographic Plates

[0050] 1) Use ultraviolet light to perform surface hydrophilic treatment on the glass substrate;

[0051] 2) Add 0.35 mL of silane coupling agent W-78 and 1.0 mL of formaldehyde to 1000 mL of 0.45% gelatin solution, and then use an extrusion coating method to evenly coat one surface of the substrate to obtain the bottom layer that adheres to the substrate.

[0052] 3) Weigh 20g of transition metal-doped silver halide emulsion, then add 0.0125g of fluorocarbon 203, coat it onto the bottom surface of the substrate, and after drying, a holographic dry plate is obtained, wherein the thickness of the silver halide photosensitive layer is 5μm.

[0053] Performance testing:

[0054] a. The latex obtained in step 1) was observed using a scanning electron microscope and found to be in the form of latex particles, with a particle size of approximately 80 nm (e.g., ...). Figure 1 (As shown).

[0055] b. The holographic plate was tested using a spectral sensitivity meter, with a test range of 340nm-465nm. The image density at different wavelengths was measured to obtain the spectral range of the holographic plate (e.g., ...). Figure 2 (As shown).

[0056] c. Exposure was performed using 355nm laser pulses with nanosecond and picosecond pulses, respectively, with different laser energy densities set. After exposure, development and fixing processes were carried out, and the density was measured using a transmission densitometer. A graph was plotted with the lg value of the exposure amount on the x-axis and the density value on the y-axis, which is the picosecond response curve of the holographic plate in this embodiment (e.g., Figure 3 (As shown). By Figure 3 It can be seen that the holographic dry plate in this implementation has a very good response at picoseconds.

[0057] d. Using interference to replicate a 2500 lp / mm untilted holographic grating, the diffraction efficiency of the holographic grating under different exposure levels was measured. The results showed that the diffraction efficiency of the holographic plate in this embodiment was above 0.1%, indicating that the resolution of the holographic plate could reach 2500 lp / mm.

[0058] Example 2

[0059] A holographic dry plate, the preparation method of which is the same as in Example 1, the only difference being that steps 1) and 2) in the method for preparing the transition metal-doped silver halide emulsion in step (a) are different, specifically:

[0060] 1) Weigh 37.5g of AgNO3 and dissolve it in 220.5mL of deionized water to form a silver salt solution;

[0061] 2) Weigh 7.71g KBr, 9.41g NaCl, and 2.39g KI and dissolve them in 240mL deionized water to form a chlorobromoiodine solution. Then add 1.35mL of 10... -2 Potassium iridate at mol / L yields a chlorobromoiodine solution containing transition metals.

[0062] Comparative Example 1

[0063] A holographic dry plate, prepared in the same way as in Example 1, except that the method for preparing the transition metal-doped silver halide emulsion in step (a) is different. Specifically:

[0064] 1) Weigh 37.5g of AgNO3 and dissolve it in 220.5mL of deionized water to form a silver salt solution;

[0065] 2) Weigh 7.71g KBr, 9.41g NaCl and 2.39g KI and dissolve them in 240mL deionized water to form a chlorobromoiodine solution;

[0066] 3) Weigh 90g of gelatin and dissolve it in 1800mL of deionized water to form a gelatin solution. Add 13g of polyvinylpyrrolidone to the solution to obtain a gelatin solution containing a surfactant.

[0067] 4) Using a computationally controlled dual-injection emulsifier, the silver salt solution and chlorobromoiodine solution were added at a feeding rate of 88 mL / min. After reacting for 5 minutes, the product was bagged and frozen in a refrigerator (0-4℃) to obtain crude latex. After freezing, the emulsion was washed with 2.5% sodium sulfate solution to remove impurities such as salt, obtaining purified latex.

[0068] 5) Weigh 40g of the purified latex, adjust the pH to 6.0 with 10% HAc, add 0.33mL of 0.1% sodium thiosulfate and 5.0mL of 0.0167% chloroauric acid, and perform chemical sensitization for 60min to obtain the final product.

[0069] Comparative Example 2

[0070] A holographic dry plate, the preparation method of which is the same as in Example 1, the only difference being that steps 1) and 2) in the method for preparing the transition metal-doped silver halide emulsion in step (a) are different, specifically:

[0071] 1) Weigh 37.5g of AgNO3 and dissolve it in 220.5mL of deionized water to form a silver salt solution;

[0072] 2) Weigh 7.71g KBr, 9.41g NaCl, and 2.39g KI and dissolve them in 240mL deionized water to form a chlorobromoiodine solution. Then add 1.35mL of 10... -2 Ferric thiocyanate at mol / L yields a chlorobromoiodine solution containing transition metals.

[0073] Performance Testing: Different holographic plates were exposed using a picosecond pulsed 355nm laser with varying laser energy densities. After exposure, development and fixing processes were performed, and the density was measured using a transmission densitometer. A graph was plotted with laser energy density on the x-axis and image density on the y-axis. The results show that, under picosecond laser exposure, the image density of the holographic plate in this comparative example does not increase with increasing laser energy density. This result also indicates that only doping with specific transition metals can improve the picosecond responsivity of the holographic plate.

[0074] Experimental Example 1

[0075] The picosecond response of the holographic plates prepared in Comparative Example 2 and Comparative Example 1 were compared using the following steps:

[0076] Different holographic plates were exposed using a picosecond pulsed 355nm laser with varying laser energy densities. After exposure, development and fixing processes were performed, and the density was measured using a transmission densitometer. A graph was plotted with laser energy density on the x-axis and image density on the y-axis (results are shown below). Figure 4 (As shown).

[0077] Depend on Figure 4 It can be seen that, under picosecond laser exposure, the image density of the holographic plate prepared in Comparative Example 1 does not increase with the increase of laser energy density. However, under picosecond laser exposure, the image density of the holographic plate prepared in Example 2 increases to a certain extent with the increase of laser energy density. This result also indicates that doping with specific transition metals can improve the picosecond responsivity of the holographic plate.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a holographic plate, characterized in that, The holographic plate comprises a substrate, a bottom layer, and a silver halide photosensitive layer. The silver halide photosensitive layer is adhered to the substrate through the bottom layer. Both the substrate and the bottom layer are hydrophilic. The silver halide photosensitive layer is formed by an emulsion of silver halide doped with transition metals. The method for preparing the holographic plate includes the following steps: 1) Add silane coupling agent and film-hardening agent to gelatin solution, and then use extrusion coating method to uniformly coat one surface of the substrate to obtain the bottom layer that adheres to the substrate; 2) Mix silver salt solution, chlorobromoiodine solution containing transition metal ions and gelatin solution containing surfactant to obtain a mixture, then carry out an emulsification reaction, and then let it stand at 0-4℃ to obtain crude latex. 3) The crude latex is washed to remove impurities, and purified latex is obtained; 4) The purified latex is chemically sensitized, and then a surfactant is added and coated onto the bottom layer surface that is adhered to the substrate to obtain the final product.

2. The method for preparing a holographic plate according to claim 1, characterized in that, The transition metal is selected from one or more of chromium, manganese, cobalt, nickel, copper, zinc, yttrium, zirconium, ruthenium, rhodium, palladium, cadmium, osmium, iridium, and platinum.

3. The method for preparing a holographic plate according to claim 1, characterized in that, In the transition metal-doped silver halide emulsion, the molar ratio of the transition metal to silver halide is 10. -6 -10 -1 :

1.

4. The method for preparing a holographic plate according to claim 1, characterized in that, The thickness of the silver halide photosensitive layer is 1-10 μm.

5. The method for preparing a holographic plate according to claim 1, characterized in that, In step 2), the mass concentration of the silver salt solution is 1%-20%.

6. The method for preparing a holographic plate according to claim 1, characterized in that, In step 2), the molar ratio of chloride ions, bromide ions and iodide ions in the chlorobromoiodine solution containing transition metal ions is 20-80:15-55:

5.

7. The method for preparing a holographic plate according to claim 1, characterized in that, In step 2), the molar ratio of silver ions, transition metal ions, and bromide ions in the mixture is 1:

10. -6 -10 -1 0.5-10.

8. The method for preparing a holographic plate according to claim 1, characterized in that, In step 1), the hardening agent is an ethylene-based or aldehyde-based agent.

9. The method for preparing a holographic plate according to claim 1, characterized in that, In step 2) or step 4), the surfactant is a fluorocarbon surfactant, anionic surfactant, or nonionic surfactant.

10. The method for preparing a holographic plate according to claim 1, characterized in that, In step 2), the emulsification reaction takes 0.5 min to 30 min.

11. The method for preparing a holographic plate according to claim 1, characterized in that, In step 4), the chemical sensitization treatment includes the following steps: The pH of the purified latex is adjusted to 4-8, a chemical sensitizer is added, and the reaction is carried out at 40-60 °C; wherein the chemical sensitizer is selected from one or more of Na2S2O3, HAuCl4, and NH4SCN.

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