Photopolymer type holographic recording medium, grating and preparation method and equipment thereof

Abstract

The invention discloses a photopolymer type holographic recording medium, a volume holographic grating, a preparation method of the volume holographic grating and holographic equipment, and relates to the technical field of holographic materials. The photopolymer type holographic recording medium comprises film-forming resin, epoxy resin, a first photosensitive initiation system, a second photosensitive initiation system, a chain transfer agent and an additive, wherein the film-forming resin is subjected to a first polymerization reaction under the action of the first photosensitive initiation system under a first illumination condition, and the epoxy resin is subjected to a second polymerization reaction under the action of the second photosensitive initiation system under a second illumination condition; the absorption spectrum of the first photosensitive initiation system is different from the absorption spectrum of the second photosensitive initiation system. According to the photopolymer type holographic recording medium provided by the invention, the film forming time of the photopolymer can be shortened, and the production efficiency of the volume holographic grating is improved.

Description

Technical Field

[0001] The present application relates to the technical field of holographic materials, and in particular to a photopolymer holographic recording medium, a volume holographic grating and a preparation method thereof, and a holographic device. Background Art

[0002] Augmented Reality (AR) technology based on holographic waveguide systems has great application potential. The core optical element of holographic waveguide systems is volume holographic gratings. Photopolymers are the preferred recording medium for preparing volume holographic gratings.

[0003] In the related art, photopolymers are divided into volatile photopolymers and second-order reaction photopolymers. Volatile photopolymers are formed into films by solvent evaporation during the preparation process. The solvent evaporation process is slow and time-consuming, and it often takes several days to evaporate at room temperature. Second-order reaction photopolymers need to be polymerized under catalyst conditions, but the reaction time often also takes several days.

[0004] Although the preparation time of these two types of photopolymers can be shortened by heating, it still takes several hours to prepare the product. In addition, heating may also cause the film-forming resin to polymerize, thereby reducing the optical performance of the prepared volume holographic grating.

[0005] Therefore, existing volume holographic gratings have the problems of long preparation time, poor production efficiency and low optical performance. Summary of the invention

[0006] Based on this, the present application provides a photopolymer holographic recording medium, a volume holographic grating and a preparation method thereof, and a holographic device, which can reduce the film-forming time of the photopolymer and improve the production efficiency of the volume holographic grating.

[0007] In a first aspect, the present application provides a photopolymer holographic recording medium, the photopolymer holographic recording medium comprising: a film-forming resin, an epoxy resin, a first photosensitive initiation system, a second photosensitive initiation system, a chain transfer agent and an additive;

[0008] Among them, the film-forming resin undergoes a first polymerization reaction under the first lighting condition and the action of the first photosensitive initiator system, and the epoxy resin undergoes a second polymerization reaction under the second lighting condition and the action of the second photosensitive initiator system, and the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

[0009] In a second aspect, the present application provides a method for preparing a volume holographic grating, the method comprising:

[0010] The film-forming resin, the epoxy resin, the first photosensitive initiation system, the second photosensitive initiation system, the chain transfer agent and the additive are uniformly mixed to prepare a mixed solution of the photopolymer type holographic recording medium;

[0011] Evenly distributing the mixed solution of the photopolymer holographic recording medium on the surface of the substrate, and irradiating the mixed solution under a first illumination condition to cause the film-forming resin to undergo a first polymerization reaction with the first photosensitive initiation system;

[0012] The mixed solution is irradiated under a second illumination condition to cause a second polymerization reaction between the epoxy resin and the second photosensitive initiator system to produce a volume holographic grating; wherein the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

[0013] In a third aspect, the present application provides a volume holographic grating, wherein the photopolymer holographic recording medium used in the volume holographic grating includes the photopolymer holographic recording medium described above, or is prepared by the preparation method of the volume holographic grating described above.

[0014] The embodiments of the present application provide a photopolymer holographic recording medium, a volume holographic grating and a preparation method thereof, and a holographic device. The photopolymer holographic recording medium includes a film-forming resin, an epoxy resin, a first photosensitive initiator system, a second photosensitive initiator system, a chain transfer agent, and an additive. The film-forming resin undergoes a first polymerization reaction under a first illumination condition and under the action of a first photosensitive initiator system, and the epoxy resin undergoes a second polymerization reaction under a second illumination condition and under the action of a second photosensitive initiator system. The absorption spectrum of the first photosensitive initiator system is different from that of the second photosensitive initiator system. The photopolymer holographic recording medium provided in the present application includes two different reaction stages. In the first reaction stage, the film-forming resin can be polymerized into a film by light irradiation, and in the second reaction stage, a volume holographic grating can be formed by cationic ring-opening polymerization through interference exposure. Since the reaction speeds of the two reaction stages are very fast, the film-forming time of the photopolymer can be greatly improved. The film can be formed after 2-10 minutes of light irradiation, and the production efficiency of the volume holographic grating is improved. At the same time, since the volume holographic grating is quickly formed by cationic polymerization in the second reaction stage, the prepared volume holographic grating has high photosensitivity and the required exposure amount is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flowchart of the steps of a method for preparing a volume holographic grating provided in an embodiment of the present application;

[0016] Figure 2 A schematic diagram of the diffraction efficiency curves of Sample 1, Sample 3 and Sample 5 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0019] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present application, and have no special meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner.

[0020] In the related art, the volatile photopolymer forms a film by solvent volatilization during the preparation process. The solvent evaporates slowly and takes a long time. It often takes several days to evaporate at room temperature. The second-order reaction photopolymer needs to be polymerized under catalyst conditions, but the reaction time often takes several days. Although the preparation time of these two types of photopolymers can be shortened by heating, it still takes several hours to prepare the product. In addition, heating may also cause the film-forming resin to polymerize, thereby reducing the performance of the obtained material.

[0021] To solve the above problems, the embodiments of the present application provide a photopolymer holographic recording medium, a volume holographic grating and a preparation method thereof, and a holographic device. The photopolymer holographic recording medium has a short film-forming time, high production efficiency, high photosensitivity, and a small exposure amount.

[0022] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0023] The embodiment of the present application provides a photopolymer holographic recording medium, which includes: a film-forming resin, an epoxy resin, a first photosensitive initiator system, a second photosensitive initiator system, a chain transfer agent and an additive; wherein the film-forming resin undergoes a first polymerization reaction under a first light condition and under the action of a first photosensitive initiator system, and the epoxy resin undergoes a second polymerization reaction under a second light condition and under the action of a second photosensitive initiator system, and the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

[0024] It should be noted that the photopolymer holographic recording medium material generally comprises a film-forming resin with a low refractive index and a writing monomer with a high refractive index. In the embodiment of the present application, the epoxy resin is equivalent to the writing monomer.

[0025] Epoxy resin is a high molecular polymer with the molecular formula (C 11 H 12 O 3 ) n Epoxy resin is a general term for a class of polymers containing two or more epoxy groups in the molecule. It is the polycondensation product of epichlorohydrin and bisphenol A or polyol. Due to the chemical activity of the epoxy group, it can be opened by a variety of compounds containing active hydrogen, and cured and cross-linked to form a network structure. The refractive index of epoxy resin is greater than 1.5.

[0026] In an embodiment of the present application, the first photosensitive initiation system is used to initiate a first polymerization reaction of the film-forming resin under a first illumination condition. The second photosensitive initiation system is used to initiate a second polymerization reaction of the epoxy resin under a second illumination condition. The absorption spectrum of the first photosensitive initiation system is different from the absorption spectrum of the second photosensitive initiation system. Therefore, under the first illumination condition, the film-forming resin will undergo a first polymerization reaction, while the epoxy resin will not undergo a second polymerization reaction. Under the second illumination condition, the epoxy resin will undergo a second polymerization reaction, while the film-forming resin will not undergo the first polymerization reaction. Therefore, by changing different illumination conditions, the film-forming resin and the epoxy resin can undergo polymerization reactions one after another, thereby greatly improving the film-forming time of the photopolymer and improving the production efficiency of the volume holographic grating. At the same time, since the second polymerization reaction is to quickly form a volume holographic grating through cationic polymerization, the prepared volume holographic grating also has high photosensitivity and requires a small exposure amount.

[0027] In some embodiments, the mass ratio of film-forming resin, epoxy resin, first photosensitive initiator system, second photosensitive initiator system, chain transfer agent and additives is (10-60): (30-70): (0.1-4): (0.1-4): (0.1-3): (0.1-7).

[0028] The raw materials of each component in the photopolymer holographic recording medium are described below by taking parts by weight as an example.

[0029] Exemplarily, the film-forming resin may be 10 parts to 60 parts, such as 10 parts, 20 parts, 40 parts, 50 parts, or 60 parts.

[0030] Exemplarily, the epoxy resin may be 30 parts to 70 parts, such as 30 parts, 40 parts, 50 parts, 60 parts, or 70 parts.

[0031] Exemplarily, the first photosensitive initiator system may be 0.1 parts to 4 parts, such as 0.1 parts, 1 parts, 2.5 parts, 3 parts, or 4 parts.

[0032] Exemplarily, the second photosensitive initiator system may be 0.1 parts to 4 parts, such as 0.1 parts, 1 parts, 2.5 parts, 3 parts, or 4 parts.

[0033] Exemplarily, the chain transfer agent may be 0.1 parts to 3 parts, such as 0.1 parts, 1 parts, 2 parts, 2.5 parts, or 3 parts.

[0034] Exemplarily, the additive may be 0.1 parts to 7 parts, such as 0.1 parts, 1 parts, 3 parts, 5.5 parts, or 7 parts.

[0035] It is understandable that the present application can achieve full synergistic effect of the components by reasonably controlling the addition amount of each component, and will not cause the holographic performance of the final photopolymer holographic recording medium to deteriorate due to too much or too little of a certain component, thereby ensuring that the comprehensive holographic performance of the final photopolymer holographic recording medium is better.

[0036] Exemplarily, the holographic performance may include optical performance parameters such as exposure, diffraction efficiency, and sensitivity.

[0037] For example, by controlling the film-forming resin at 10 to 60 parts and the first photosensitive initiator system at 0.1 to 4 parts, the film-forming resin can undergo a first polymerization reaction to form a film under the first light conditions and the action of the first photosensitive initiator system, thereby providing support for other components.

[0038] For example, by controlling the epoxy resin at 30 to 70 parts and the second photosensitive initiator system at 0.1 to 4 parts, the epoxy resin can form a writing monomer with a higher refractive index, and the epoxy resin can undergo a second polymerization reaction under the second lighting conditions and the action of the second photosensitive initiator system to form a volume holographic grating with a refractive index modulation.

[0039] For example, by controlling the chain transfer agent to 0.1 to 3 parts, the polymer chain length can be controlled within a certain reasonable range and the degree of polymerization can be effectively prevented, thereby ensuring that the final holographic recording medium has the required optical properties and diffraction efficiency.

[0040] For example, controlling the additive to 0.1 to 7 parts, taking the additive as a leveling agent as an example, can effectively improve the uniformity of the mixed liquid, improve fluidity, and reasonably control costs.

[0041] In some embodiments, the film-forming resin is at least one of an acrylate monomer, a methacrylate monomer, and an allyl ether monomer; wherein the refractive index of the acrylate monomer, the methacrylate monomer, and the allyl ether monomer is less than 1.5.

[0042] Exemplarily, the film-forming resin may be composed of any one of an acrylate monomer, a methacrylate monomer, and an allyl ether monomer, or any two of an acrylate monomer, a methacrylate monomer, and an allyl ether monomer, or an acrylate monomer, a methacrylate monomer, and an allyl ether monomer, and is not specifically limited here. However, since the acrylate monomer, the methacrylate monomer, and the allyl ether monomer are film-forming resins, the refractive index of the acrylate monomer, the methacrylate monomer, and the allyl ether monomer is less than 1.5.

[0043] In some embodiments, the acrylate monomer can be selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, β-carboxyethyl acrylate, ethyl acrylate-β-carboxyethyl acrylate, butyl acrylate-β-carboxyethyl acrylate, octyl acrylate-β-carboxyethyl acrylate, dodecyl acrylate-β-carboxyethyl acrylate, hexadecyl acrylate-β-carboxyethyl acrylate, cyclohexyl acrylate-β-carboxyethyl acrylate, phenyl acrylate-β-carboxyethyl acrylate, tetrahydrofurfuryl ethyl acrylate, glycidyl acrylate, and β-carboxyethyl acrylate.

[0044] In some embodiments, the methacrylate monomer can be selected from methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, 2-methylbutyl methacrylate, 3-methylbutyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, methyl ... One or more of hexadecyl methacrylate, heptadecyl methacrylate, octadecyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-propoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-phenoxyethyl methacrylate, and 2-benzyloxyethyl methacrylate.

[0045] In some embodiments, the allyl ether monomer can be selected from allyl methyl ether, allyl ethyl ether, allyl propyl ether, allyl butyl ether, allyl isobutyl ether, allyl amyl ether, allyl hexyl ether, allyl heptyl ether, allyl octyl ether, allyl nonyl ether, allyl decyl ether, allyl undecyl ether, allyl dodecayl ether, allyl tridecyl ether, allyl tetradecyl ether, allyl pentadecyl ether, allyl hexadecyl ether, allyl heptadecayl ether, allyl octadecyl ether, allyl isobornyl ether, allyl cyclohexyl ether, allyl phenyl ether, allyl One or more of benzyl ether, allyl 2-ethylhexyl ether, allyl lauryl ether, allyl stearyl ether, allyl 2-hydroxyethyl ether, allyl 2-hydroxypropyl ether, allyl 2-methoxyethyl ether, allyl 2-ethoxyethyl ether, allyl 2-propoxyethyl ether, allyl 2-butoxyethyl ether, allyl 2-phenoxyethyl ether, allyl 2-benzyloxyethyl ether, allyl tetrahydrofurfuryl ether, allyl tetrahydrofuroate ether, allyl tetrahydrofuran ether, and allyl-β-carboxyethyl ether.

[0046] In some embodiments, the epoxy has a refractive index greater than 1.5.

[0047] Preferably, the refractive index of the epoxy resin is generally greater than 1.55.

[0048] In some embodiments, the epoxy resin can be selected from bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, glycerol triglycidyl ether, n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butanediol diglycidyl ether, pentanediol diglycidyl ether, glycerol triglycidyl ether, 3,4-epoxycyclohexene methyl -3,4-Epoxycyclohexene ester, polyethylene glycol diglycidyl ether, diglycidyl ether, diethylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, furfuryl glycidyl ether, 2-biphenyl glycidyl ether, pentaerythritol glycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, 1,4-butanediol glycidyl ether, trimethylolethane triglycidyl ether, 2-ethoxy phenyl glycidyl ether, 1,2-cyclohexanediol diglycidyl ether, tetrabromobisphenol A epoxy resin, diglycidyl phthalate, glycidyl p-toluenesulfonate, glycidyl butyrate, glycidyl decanoate, glycidyl octanoate, glycidyl oleate, glycidyl stearate, glycidyl laurate, glycidyl acrylate, glycidyl versatate, glycidyl palmitate, glycidyl linolenate, glycidyl linoleate, triglycidyl isocyanurate , diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, glycidyl 4-tert-butylbenzoate, 1-benzyl-4-glycidyl piperazine, triglycidyl isocyanurate (S,S,S), diglycidyl 4,5-epoxytetrahydrophthalate, 4-hydroxybutyl acrylate glycidyl ether, 3-glycidylpropyl (dimethoxy)methylsilane, triglycidylamino-meta-cresol, triglycidyl p-aminophenol.

[0049] In some embodiments, the first photosensitive initiator system includes a first photoinitiator, which can be activated by visible light and initiate a first polymerization reaction of the film-forming resin; the second photosensitive initiator system includes a photosensitizing dye, a second photoinitiator and a third photoinitiator, which can initiate a second polymerization reaction of the epoxy resin under ultraviolet light, and the photosensitizing dye can activate the second photoinitiator and the third photoinitiator by energy transfer or electron transfer under ultraviolet light.

[0050] Visible light refers to the part of the electromagnetic spectrum that can be perceived by the human eye. The visible spectrum does not have a precise range. The frequency of electromagnetic waves that can be perceived by the average human eye is between 380 and 750 THz, and the wavelength is between 780 and 400 nm. However, some people can perceive electromagnetic waves with a frequency of approximately 340 to 790 THz and a wavelength of approximately 880 to 380 nm.

[0051] Ultraviolet (UV) can refer to the general term for radiation with a frequency of 750THz to 30PHz in the electromagnetic spectrum, corresponding to a wavelength of 400nm to 10nm in a vacuum, which cannot cause human vision.

[0052] Exemplarily, the photosensitizing dye is a dye having a high electron transfer efficiency under light, including but not limited to cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, benzylcycloalkane ketone compounds, or any mixture of these compounds in any proportion.

[0053] Exemplarily, the first photoinitiator is a photoinitiator that can be activated by visible light, the second photoinitiator and the third photoinitiator are photoinitiators that can be activated by ultraviolet light, the second photoinitiator can be a free radical initiator, and the third photoinitiator can be an ultraviolet photoinitiator that can initiate cationic ring-opening polymerization in epoxy resin.

[0054] In some embodiments, the photosensitizing dye has no light energy absorption in the wavelength range of 400-410 nm, or the absorbance of the photosensitizing dye in the wavelength range of 400-410 nm is less than 100 nm. -1 cm -1 .

[0055] By controlling the photosensitizing dye to have no light absorption in the wavelength range of 400-410nm or the absorbance in the wavelength range of 400-410nm is less than 100M -1 cm -1 , so that the photosensitizer dye will not activate the second photoinitiator and the third photoinitiator under visible light irradiation, and will activate the second photoinitiator and the third photoinitiator under ultraviolet light irradiation. And because the absorbance of the photosensitizer dye in the wavelength range of 400-410nm is controlled to be lower than 100M -1 cm -1 , even if the photosensitizing dye activates the second photoinitiator and the third photoinitiator under visible light irradiation, the second photoinitiator and the third photoinitiator will not be activated in large quantities to initiate the cationic ring-opening polymerization reaction.

[0056] In some embodiments, the first photoinitiator can be selected from one or more of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), ethyl 1-(6-o-methylbenzoyl-N-ethylcarbazole)-1-ethanone oxime, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0057] In some embodiments, the second photoinitiator can be selected from one or more of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylpropane-1-one, ethyl p-dimethylaminobenzoate, phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, 2,2-dimethoxy-phenylacetophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0058] In some embodiments, the third photoinitiator can be one or more of diaryliodonium salts or triarylsulfonium salts.

[0059] Exemplary diaryliodonium salts include, but are not limited to, diaryliodonium tetrafluoroborate, diaryliodonium hexafluorophosphate, diaryliodonium trifluoromethanesulfonate, diphenyliodonium salt, dinaphthyliodonium salt, biphenyliodonium salt, phenylnaphthyliodonium salt, di(4-methylphenyl)iodonium salt, di(4-chlorophenyl)iodonium salt, di(4-bromophenyl)iodonium salt, di(4-methoxyphenyl)iodonium salt, di(4-ethoxyphenyl)iodonium salt, di(4-hydroxy ... (4-nitrophenyl)iodonium salt, bis(4-aminophenyl)iodonium salt, bis(4-hydroxyphenyl)iodonium salt, bis(4-carboxyphenyl)iodonium salt, bis(3-methylphenyl)iodonium salt, bis(3-chlorophenyl)iodonium salt, bis(2-methylphenyl)iodonium salt, bis(2-chlorophenyl)iodonium salt, bis(2-nitrophenyl)iodonium salt, bis(benzyl)iodonium salt, bis(α-naphthyl)iodonium salt, bis(β-naphthyl)iodonium salt, and the like.

[0060] Exemplary, triarylsulfonium salts include, but are not limited to, triphenylsulfonium hexafluorophosphate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium trifluoromethanesulfonate, 4-chlorophenyldiphenylsulfonium hexafluorophosphate, 3-nitrophenyldiphenylsulfonium hexafluorophosphate, 4-acetamidophenyldiphenylsulfonium hexafluorophosphate, 3-benzoylphenyldiphenylsulfonium hexafluorophosphate, 4-tolyldiphenylsulfonium hexafluorophosphate, and the like.

[0061] In some embodiments, the photosensitizing dye can be selected from one or more of new methylene blue, thionine, basic yellow, pinacol chloride, rhodamine 6G, gallocyanine, ethyl violet, Victoria blue R, lapis lazuli blue, methylene blue, Astrazon Orange G, Darrow red, pyrrole red Y, basic red 29, quinaldine red, crystal violet, ethyl violet, brilliant green, pyri11lium I, azure A, crystal violet white nitrile, and malachite green white nitrile.

[0062] In some embodiments, the chain transfer agent is a thiol compound, including but not limited to one or more of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, and 4-methyl-4H-1,2,4-triazole-3-thiol. Controlling a certain amount of the chain transfer agent can control the polymer chain length within a certain reasonable range and effectively prevent excessive polymerization, thereby ensuring that the final holographic recording medium has the desired optical properties and diffraction efficiency.

[0063] In some embodiments, the additive includes one or more of a defoamer, a leveling agent, a plasticizer, a UV absorber, a light stabilizer, and an antioxidant.

[0064] Exemplarily, when the additive includes a defoaming agent, the content of the defoaming agent is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0065] Exemplarily, when the additive includes a leveling agent, the content of the leveling agent is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0066] Exemplarily, when the additive includes a plasticizer, the content of the plasticizer is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0067] Illustratively, when the additive includes an ultraviolet absorber, the content of the ultraviolet absorber is no more than 3% based on the total mass of the photopolymer type holographic recording medium.

[0068] Exemplarily, when the additive includes a light stabilizer, the content of the light stabilizer is no more than 3% based on the total mass of the photopolymer type holographic recording medium.

[0069] Exemplarily, when an antioxidant is included in the additive, the content of the antioxidant is no more than 3% based on the total mass of the photopolymer-type holographic recording medium.

[0070] Exemplarily, the defoaming agent is a silicone defoaming agent, such as BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, BYK-1760 produced by BYK, DC65, AFE-7820 produced by Dow Corning, or a mixture of these defoaming agents in any proportion.

[0071] Exemplarily, the leveling agent is an organosilicon surface additive, such as BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566 produced by BYK, or a mixture of these surface additives in any proportion.

[0072] Exemplarily, the plasticizer is toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate or a mixture of these compounds in any ratio.

[0073] Exemplary ultraviolet absorbers include, but are not limited to, 2-hydroxy-4-n-octyloxybenzophenone, 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol, N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-oxalamide, 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol, 2-(2H-benzotriazol-2)-4,6-di(1-methyl-1-phenylethyl)phenol, or mixtures of these absorbers in any proportion.

[0074] Exemplarily, the light stabilizer includes, but is not limited to, light stabilizer 944, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, light stabilizer 622, or a mixture of these stabilizers in any ratio.

[0075] Exemplary antioxidants include, but are not limited to, Irganox 1010, Irganox 168, Irganox 1076, Irganox 1098, Irganox MD1024, Irganox 1035, BASF liquid antioxidant 1135, Irganox B225, Irganox PS800 (DLTP), Irganox B900, Irganox 3114, Irganox 245, Irganox B215, Irganox PS-802FL, Irganox Borchors Ascinin@Special, Irganox Borchors Ascinin@P, or any mixture of these antioxidants in any proportion.

[0076] In some embodiments, the photopolymer holographic recording medium may further include a solvent, and the weight percentage of the solvent in the photopolymer holographic recording medium is less than or equal to 3 parts.

[0077] In a specific embodiment, the solvent can be selected from at least one of dichloromethane, ethyl acetate, petroleum ether, n-hexane, toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, ether, pentane, acetone, dichloroethane, chloroform, methanol, tetrahydrofuran, trichloroethane, carbon tetrachloride, ethanol, butanone, benzene, cyclohexane, acetonitrile, isopropanol, ethylene glycol dimethyl ether, propionitrile, heptane, pyridine, butanol, ethylene glycol-methyl ether, octane, butyl acetate, chlorobenzene, ethylene glycol-ethyl ether, cyclohexanone, and dimethyl sulfoxide. These solvents have good compatibility with other components, so that each component is fully dissolved, and the solvent is convenient for subsequent drying and removal.

[0078] The following describes a method for preparing a volume holographic grating provided in the present application.

[0079] like Figure 1 As shown, the embodiment of the present application also provides a method for preparing a volume holographic grating, comprising the following steps:

[0080] S101, uniformly mixing a film-forming resin, an epoxy resin, a first photosensitive initiation system, a second photosensitive initiation system, a chain transfer agent and an additive to obtain a mixed solution of a photopolymer type holographic recording medium;

[0081] S102, uniformly distributing a mixed solution of a photopolymer holographic recording medium on a surface of a substrate, and irradiating the mixed solution under a first illumination condition, so that a first polymerization reaction occurs between the film-forming resin and the first photosensitive initiation system;

[0082] S103, irradiating the mixed solution under a second illumination condition to cause a second polymerization reaction between the epoxy resin and the second photosensitive initiator system to produce a volume holographic grating; wherein the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

[0083] It should be noted that the relevant embodiments of the film-forming resin, epoxy resin, first photosensitive initiator system, second photosensitive initiator system, chain transfer agent and additives can refer to the above embodiments and will not be repeated here.

[0084] For example, all components of the photopolymer holographic recording medium are mixed uniformly, filtered through a filter membrane to obtain a mixed solution of the photopolymer holographic recording medium, and the mixed solution is evenly distributed on the surface of the substrate by inkjet printing, scraping, spin coating, etc., and then illuminated by a 405nm LED lamp (5-100mW / cm 2) for 2-10 minutes (first illumination condition) to initiate a first polymerization reaction between the film-forming resin and the first photosensitive initiator system to obtain a photopolymer film. Two beams of light are used for coherent exposure. After the exposure, the photopolymer film is irradiated with ultraviolet light (second illumination condition) to cause cationic ring-opening polymerization. After the polymerization is completed, a volume holographic grating can be obtained.

[0085] The photopolymer holographic recording medium provided in the embodiment of the present application has a fast photopolymerization reaction speed and can form a film after only 2-10 minutes of light exposure, thereby significantly shortening the film formation time of the photopolymer. The photosensitivity of the prepared photopolymer holographic recording medium is greater than 100cm 2 / mJ, only less than 30mJ / cm 2 An exposure amount of can produce a transmission / reflection volume holographic grating with a diffraction efficiency higher than 95%.

[0086] As can be seen from the above, the preparation method of the photopolymer holographic recording medium proposed in the present application has a photopolymer holographic recording medium with fewer preparation steps, simple operation, easy implementation conditions and shorter film-forming time.

[0087] The embodiment of the present application further provides a volume holographic grating, wherein the photopolymer holographic recording medium used in the volume holographic grating includes the photopolymer holographic recording medium described in any of the above embodiments or is prepared by the preparation method of the volume holographic grating described in any of the above embodiments.

[0088] As can be seen from the above, the volume holographic grating proposed in this application has a short film-forming time, high production efficiency, and high photosensitivity, with a sensitivity greater than 100cm 2 / mJ, and the required exposure is small, only less than 30mJ / cm 2 An exposure amount of can produce a transmission / reflection volume holographic grating with a diffraction efficiency higher than 95%.

[0089] An embodiment of the present application provides a volume holographic optical waveguide, wherein the volume holographic optical waveguide includes the volume holographic grating as described above.

[0090] An embodiment of the present application provides a holographic device, which includes the volume holographic optical waveguide as described above.

[0091] The photopolymer holographic recording medium and volume holographic grating of the present invention are described below with reference to specific embodiments.

[0092] Example 1

[0093] In this embodiment, the photopolymer holographic recording medium 1-1 includes the following raw materials of various components in parts by weight:

[0094] The first component: 25 parts of film-forming resin, the film-forming resin includes an acrylate monomer, and the acrylate monomer is 25 parts of methyl acrylate.

[0095] The second component: 40 parts of epoxy resin; the epoxy resin is bisphenol A type epoxy resin.

[0096] The third component: 3 parts of the first photosensitive initiation system; the first photosensitive initiation system includes a first photoinitiator, and the first photoinitiator is ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

[0097] The fourth component: 2 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, the third photoinitiator is 0.3 parts of diaryliodonium tetrafluoroborate, and the photosensitizing dye is 1.4 parts of pinacol cyanol chloride.

[0098] The fifth component: 0.3 parts of chain transfer agent; the chain transfer agent is 0.3 parts of mercaptoethanol.

[0099] The sixth component: 3 parts of additives. The additives include defoamers and leveling agents, wherein the defoamer is 1.5 parts of BYK-011 and the leveling agent is 1.5 parts of BYK-302.

[0100] Example 2

[0101] In this embodiment, the photopolymer holographic recording medium 1-2 includes the following raw materials of various components in parts by weight:

[0102] The first component: 30 parts of film-forming resin, the film-forming resin includes acrylate monomer and methacrylate monomer, the acrylate monomer is 10 parts of propyl acrylate, and the methacrylate monomer is 20 parts of ethyl methacrylate.

[0103] The second component: 45 parts of epoxy resin; the epoxy resin is glycerol triglycidyl ether.

[0104] The third component: 2.5 parts of the first photosensitive initiator system; the first photosensitive initiator system includes a first photoinitiator, and the first photoinitiator is 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime).

[0105] The fourth component: 2.5 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.5 parts of 2,2-dimethoxy-phenylacetophenone, the third photoinitiator is 0.5 parts of di(4-methoxyphenyl)iodonium salt, and the photosensitizing dye is 1.5 parts of ethyl violet.

[0106] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of dodecyl mercaptan.

[0107] The sixth component: 6 parts of additives. The additives include defoamer, leveling agent, plasticizer, UV absorber, light stabilizer and antioxidant, wherein the defoamer BYK-085 is taken in 1 part, the leveling agent BYK-329 is taken in 1 part, the plasticizer phthalate is taken in 1 part, the UV absorber 2-hydroxy-4-n-octyloxybenzophenone is taken in 1 part, the light stabilizer 944 is taken in 1 part, and the antioxidant Irganox1010 is taken in 1 part.

[0108] Example 3

[0109] In this embodiment, the photopolymer holographic recording medium 1-3 includes the following raw materials of various components in parts by weight:

[0110] The first component: 35 parts of film-forming resin, the film-forming resin includes methacrylate monomer and allyl ether monomer, the methacrylate monomer is 20 parts of undecyl methacrylate, and the allyl ether monomer is 15 parts of allyl ethyl ether.

[0111] The second component: 42 parts of epoxy resin; the epoxy resin is n-butyl glycidyl ether.

[0112] The third component: 3.5 parts of the first photosensitive initiation system; the first photosensitive initiation system includes a first photoinitiator, and the first photoinitiator is 1-(6-o-methylbenzoyl-N-ethylcarbazole)-1-ethanone oxime ethyl ester.

[0113] The fourth component: 2 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.8 parts of phenyl (2,4,6-trimethylbenzoyl) lithium phosphate, the third photoinitiator is 0.7 parts of di (4-aminophenyl) iodonium salt, and the photosensitizing dye is 0.5 parts of lapis lazuli blue.

[0114] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of hexanethiol.

[0115] The sixth component: 5 parts of additives. The additives include defoamers, leveling agents, plasticizers, ultraviolet absorbers, light stabilizers and antioxidants, wherein the defoamer BYK-1610 is taken in 0.8 parts, the leveling agent BYK-333 is taken in 1 part, the plasticizer dimethylacetamide is taken in 0.8 parts, the ultraviolet absorber 2-(5-chloro-2H-benzotriazole-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol is taken in 0.5 parts, the light stabilizer bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate is taken in 1 part, and the antioxidant Irganox 168 is taken in 0.9 parts.

[0116] Example 4

[0117] In this embodiment, the photopolymer holographic recording medium 1-4 includes the following raw materials of various components in parts by weight:

[0118] The first component: 45 parts of film-forming resin, which includes acrylate monomer, methacrylate monomer and allyl ether monomer. The acrylate monomer is 15 parts of heptadecaned acrylate, the methacrylate monomer is 15 parts of hexyl methacrylate and the allyl ether monomer is 15 parts of allyl isobornyl ether.

[0119] The second component: 40 parts of epoxy resin; the epoxy resin is ethylene glycol diglycidyl ether.

[0120] The third component: 2.8 parts of the first photosensitive initiation system; the first photosensitive initiation system includes a first photoinitiator, and the first photoinitiator is (2,4,6-trimethylbenzoyl) diphenylphosphine oxide.

[0121] The fourth component: 2.5 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 1 part of ethyl p-dimethylaminobenzoate, the third photoinitiator is 1 part of triphenylsulfonium hexafluorophosphate, and the photosensitizing dye is 0.5 parts of methylene blue.

[0122] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol.

[0123] The sixth component: 5.5 parts of additives. The additives include defoamers, leveling agents, plasticizers, ultraviolet absorbers, light stabilizers and antioxidants, wherein the defoamer BYK-1707 is taken in 1 part, the leveling agent BYK-356 is taken in 0.8 parts, the plasticizer glycerin is taken in 1 part, the ultraviolet absorber N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-oxalamide is taken in 1 part, the light stabilizer 622 is taken in 0.8 parts, and the antioxidant Irganox 1076 is taken in 0.9 parts.

[0124] Example 5

[0125] In this embodiment, the photopolymer holographic recording medium 1-5 includes the following raw materials of various components in parts by weight:

[0126] The first component: 50 parts of film-forming resin, which includes acrylate monomer, methacrylate monomer and allyl ether monomer. The acrylate monomer is 20 parts of benzyl acrylate, the methacrylate monomer is 15 parts of hexadecyl methacrylate and the allyl ether monomer is 15 parts of allyl heptadecadecyl ether.

[0127] The second component: 35 parts of epoxy resin; the epoxy resin is pentanediol diglycidyl ether.

[0128] The third component: 2.2 parts of the first photosensitive initiation system; the first photosensitive initiation system includes a first photoinitiator, and the first photoinitiator is phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide.

[0129] The fourth component: 3.5 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.8 parts of 2-hydroxy-2-methylphenylpropane-1-one, the third photoinitiator is 0.8 parts of triphenylsulfonium trifluoromethanesulfonate, and the photosensitizing dye is 1.9 parts of pyrrole red Y.

[0130] The fifth component: 1.2 parts of chain transfer agent; the chain transfer agent is 1.2 parts of 4-methyl-4H-1,2,4-triazole-3-thiol.

[0131] The sixth component: 4.5 parts of additives. The additives include defoamer, leveling agent, plasticizer, UV absorber, light stabilizer and antioxidant, wherein the defoamer BYK-1740 is taken in 0.5 parts, the leveling agent BYK-358 is taken in 0.8 parts, the plasticizer glycerin is taken in 0.5 parts, the UV absorber 2-(2H-benzotriazole-2)-4,6-bis(1-methyl-1-phenylethyl)phenol is taken in 1 parts, the light stabilizer 622 is taken in 0.8 parts, and the antioxidant Irganox MD1024 is taken in 0.9 parts.

[0132] Example 6

[0133] In this embodiment, the photopolymer holographic recording medium 1-6 includes the following raw materials of various components in parts by weight:

[0134] The first component: 42 parts of film-forming resin, the film-forming resin includes acrylate monomer, methacrylate monomer, and allyl ether monomer. The acrylate monomer is 18 parts of cyclohexyl acrylate, the methacrylate monomer is 17 parts of cyclohexyl methacrylate, and the allyl ether monomer is 7 parts of allyl 2-methoxyethyl ether.

[0135] The second component: 46 parts of epoxy resin; the epoxy resin is glycidyl linoleate.

[0136] The third component: 1.5 parts of the first photosensitive initiation system; the first photosensitive initiation system includes a first photoinitiator, and the first photoinitiator is phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide.

[0137] The fourth component: 2.6 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.7 parts of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, the third photoinitiator is 0.9 parts of di(2-chlorophenyl)iodonium salt, and the photosensitizing dye is 1 part of quinaldine red.

[0138] The fifth component: 0.9 parts of chain transfer agent; the chain transfer agent is 0.9 parts of hexanethiol.

[0139] The sixth component: 4 parts of additives. The additives include defoamer, leveling agent, plasticizer, UV absorber, light stabilizer and antioxidant, wherein the defoamer BYK-1760 is taken in 0.6 parts, the leveling agent BYK-378 is taken in 0.8 parts, the plasticizer phthalate is taken in 0.6 parts, the UV absorber 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol is taken in 0.7 parts, the light stabilizer 622 is taken in 0.8 parts, and the antioxidant Irganox PS-802FL is taken in 0.5 parts.

[0140] Example 7

[0141] In this embodiment, the photopolymer holographic recording medium 1-7 includes the following raw materials of various components in parts by weight:

[0142] The first component: 38 parts of film-forming resin, which includes acrylate monomer, methacrylate monomer and allyl ether monomer. The acrylate monomer is 12 parts of butyl acrylate-β-carboxyethyl ester, the methacrylate monomer is 14 parts of 2-propoxyethyl methacrylate, and the allyl ether monomer is 12 parts of allyl tetrahydrofuran ether.

[0143] The second component: 47 parts of epoxy resin; the epoxy resin is 4-hydroxybutyl acrylate glycidyl ether.

[0144] The third component: 1 part of the first photosensitive initiator system; the first photosensitive initiator system includes a first photoinitiator, and the first photoinitiator is 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime).

[0145] The fourth component: 2.2 parts of the second photosensitive initiator system; the second photosensitive initiator system includes a second photoinitiator, a third photoinitiator and a photosensitizing dye, wherein the second photoinitiator is 0.8 parts of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, the third photoinitiator is 0.9 parts of di(2-nitrophenyl)iodonium salt, and the photosensitizing dye is 0.5 parts of ethyl violet.

[0146] The fifth component: 0.9 parts of chain transfer agent; the chain transfer agent is 0.9 parts of phenylethyl mercaptan.

[0147] The sixth component: 3.5 parts of additives. The additives include defoamers, leveling agents, plasticizers, ultraviolet absorbers, light stabilizers and antioxidants, wherein the defoamer BYK-012 is taken in 0.6 parts, the leveling agent BYK-3455 is taken in 0.5 parts, the plasticizer phthalate is taken in 0.7 parts, the ultraviolet absorber 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol is taken in 0.6 parts, the light stabilizer 944 is taken in 0.6 parts, and the antioxidant Irganox245 is taken in 0.5 parts.

[0148] Example 8

[0149] In this example, a volume holographic grating is prepared using the photopolymer holographic recording medium provided in Examples 1-7.

[0150] Comparative Example

[0151] In this embodiment, a volume holographic grating is prepared using a photopolymer holographic recording medium provided by related technology.

[0152] Test example

[0153] The stability of the gratings after recording the gratings on the holographic recording media of Examples 1-7 and the comparative example was tested. The results are shown in Table 1.

[0154] The test method includes the following steps:

[0155] Grating preparation: Solid-state lasers with wavelengths of 633nm, 457nm, and 532nm are used as light sources. After passing through a beam expander, beam splitter, and half-wave plate, two beams with the same light intensity and a diameter of 8mm are obtained. The two beams intersect in the prepared holographic recording medium for exposure, and the light intensity is 3mW / cm 2 The detection light source is a 785nm wavelength solid laser that does not react with the recording medium. The detection light is incident on the exposure area from the Bragg angle. The transmitted light and diffracted light are monitored in real time by the photodetector, and the single grating diffraction efficiency (η) of the photopolymer holographic recording medium is calculated by formula (1).

[0156]

[0157] Where η is the diffraction efficiency, I d is the diffracted light, I t is the transmitted light, S is the photosensitivity, E is the exposure energy, and ΔE is the exposure energy when the highest diffraction efficiency is achieved.

[0158] Table 1

[0159]

[0160] It should be noted that Samples 1 to 7 are all samples made from the photopolymer holographic recording media provided in Examples 1 to 7.

[0161] Table 2

[0162]

[0163] It should be noted that Samples 1 to 7 are samples made from the photopolymer holographic recording media provided in Examples 1 to 7, and Sample 8 is a sample made from the photopolymer holographic recording medium provided in the comparative example (ie, the prior art).

[0164] In summary, refer to Table 1, Table 2 and Figure 2 The photopolymer holographic recording medium of the embodiment of the present invention has a short film-forming time and a high production efficiency, which is much higher than that of the comparative example. At the same time, the photopolymer holographic recording medium of the embodiment of the present invention also has a high photosensitivity and requires a small exposure amount, which is only less than 30 mJ / cm 2 An exposure amount of can produce a transmission / reflection volume holographic grating with a diffraction efficiency higher than 95%.

[0165] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0166] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0167] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A photopolymer holographic recording medium, characterized in that: The photopolymer holographic recording medium comprises: a film-forming resin, an epoxy resin, a first photosensitive initiation system, a second photosensitive initiation system, a chain transfer agent and an additive; Among them, the film-forming resin undergoes a first polymerization reaction under the first lighting condition and the action of the first photosensitive initiator system, and the epoxy resin undergoes a second polymerization reaction under the second lighting condition and the action of the second photosensitive initiator system, and the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

2. The photopolymer holographic recording medium according to claim 1, wherein: The mass ratio of the film-forming resin, the epoxy resin, the first photosensitive initiation system, the second photosensitive initiation system, the chain transfer agent and the additive is (10-60): (30-70): (0.1-4): (0.1-4): (0.1-3): (0.1-7).

3. The photopolymer holographic recording medium according to claim 1, wherein: The film-forming resin is at least one of an acrylate monomer, a methacrylate monomer, and an allyl ether monomer; Wherein, the refractive index of the acrylate monomer, the methacrylate monomer and the allyl ether monomer is less than 1.

5.

4. The photopolymer holographic recording medium according to claim 3, characterized in that: The acrylic acid ester monomer is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, β-carboxyethyl acrylate, ethyl acrylate-β-carboxyethyl acrylate, butyl acrylate-β-carboxyethyl acrylate, octyl acrylate-β-carboxyethyl acrylate, dodecyl acrylate-β-carboxyethyl acrylate, hexadecyl acrylate-β-carboxyethyl acrylate, cyclohexyl acrylate-β-carboxyethyl acrylate, phenyl acrylate-β-carboxyethyl acrylate, tetrahydrofurfuryl ethyl acrylate, glycidyl acrylate, and β-carboxyethyl acrylate; The methacrylate monomer is methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, 2-methylbutyl methacrylate, 3-methylbutyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, methacrylic acid ester, methyl methacrylate ... At least one of hexadecyl methacrylate, heptadecyl methacrylate, octadecyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-propoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-phenoxyethyl methacrylate, and 2-benzyloxyethyl methacrylate; The allyl ether monomer is allyl methyl ether, allyl ethyl ether, allyl propyl ether, allyl butyl ether, allyl isobutyl ether, allyl pentyl ether, allyl hexyl ether, allyl heptyl ether, allyl octyl ether, allyl nonyl ether, allyl decyl ether, allyl undecyl ether, allyl dodecayl ether, allyl tridecayl ether, allyl tetradecayl ether, allyl pentadecyl ether, allyl hexadecyl ether, allyl heptadecayl ether, allyl octadecyl ether, allyl isobornyl ether, allyl cyclohexyl ether, allyl phenyl ether, allyl benz ...phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl ether, allyl phenyl At least one of propyl 2-ethylhexyl ether, allyl lauryl ether, allyl stearyl ether, allyl 2-hydroxyethyl ether, allyl 2-hydroxypropyl ether, allyl 2-methoxyethyl ether, allyl 2-ethoxyethyl ether, allyl 2-propoxyethyl ether, allyl 2-butoxyethyl ether, allyl 2-phenoxyethyl ether, allyl 2-benzyloxyethyl ether, allyl tetrahydrofurfuryl ether, allyl tetrahydrofuroate ether, allyl tetrahydrofuran ether, and allyl-β-carboxyethyl ether.

5. The photopolymer holographic recording medium according to claim 1, wherein: The refractive index of the epoxy resin is greater than 1.

5.

6. The photopolymer holographic recording medium according to claim 5, characterized in that: The epoxy resin is bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, glycerol triglycidyl ether, n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butanediol diglycidyl ether, pentanediol diglycidyl ether, glycerol triglycidyl ether, 3,4-epoxycyclohexenemethyl-3,4-cyclohexene Oxycyclohexene ester, polyethylene glycol diglycidyl ether, diglycidyl ether, diethylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, furfuryl glycidyl ether, 2-biphenyl glycidyl ether, pentaerythritol glycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, 1,4-butanediol glycidyl ether, trimethylolethane triglycidyl ether, 2-ethoxyphenyl glycidyl ether Glycidyl ether, 1,2-cyclohexanediol diglycidyl ether, tetrabromobisphenol A epoxy resin, diglycidyl phthalate, glycidyl p-toluenesulfonate, glycidyl butyrate, glycidyl decanoate, glycidyl octanoate, glycidyl oleate, glycidyl stearate, glycidyl laurate, glycidyl acrylate, glycidyl tert-butyl carbonate, glycidyl palmitate, glycidyl linolenate, glycidyl linoleate, triglycidyl isocyanurate, At least one of hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, 4-tert-butylbenzoic acid glycidyl ester, 1-benzyl-4-glycidyl piperazine, isocyanuric acid (S,S,S) triglycidyl ester, 4,5-epoxytetrahydrophthalic acid diglycidyl ester, 4-hydroxybutyl acrylate glycidyl ether, 3-glycidylpropyl (dimethoxy)methylsilane, triglycidylamino-meta-cresol, and triglycidylpara-aminophenol.

7. The photopolymer holographic recording medium according to claim 1, wherein: The first photosensitive initiation system includes a first photoinitiator, which can be activated by visible light and initiate a first polymerization reaction of the film-forming resin; The second photosensitive initiation system includes a photosensitizing dye, a second photoinitiator and a third photoinitiator. The second photoinitiator and the third photoinitiator can initiate a second polymerization reaction of the epoxy resin under ultraviolet light irradiation. The photosensitizing dye can activate the second photoinitiator and the third photoinitiator through energy transfer or electron transfer under ultraviolet light irradiation.

8. The photopolymer holographic recording medium according to claim 7, characterized in that: The photosensitizer has no light energy absorption within the wavelength range of 400-410 nm, or the absorbance of the photosensitizer within the wavelength range of 400-410 nm is less than 100 nm. -1 cm -1 .

9. The photopolymer holographic recording medium according to claim 7, wherein: The first photoinitiator is at least one of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), ethyl 1-(6-o-methylbenzoyl-N-ethylcarbazole)-1-ethanone oxime, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; The second photoinitiator is at least one of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylpropane-1-one, ethyl p-dimethylaminobenzoate, phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, 2,2-dimethoxy-phenylacetophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone; The third photoinitiator is a diaryl iodonium salt or a triaryl sulfonium salt; The photosensitizing dye is at least one of new methylene blue, thionine, basic yellow, pinacol chloride, rhodamine 6G, gallocyanine, ethyl violet, Victoria blue R, lapis lazuli blue, methylene blue, Astrazon Orange G, Darrow red, pyrrole red Y, basic red 29, quinaldine red, crystal violet, ethyl violet, brilliant green, pyri11lium I, azure A, crystal violet white nitrile, and malachite green white nitrile.

10. A method for preparing a volume holographic grating, characterized in that: The method comprises: The film-forming resin, the epoxy resin, the first photosensitive initiation system, the second photosensitive initiation system, the chain transfer agent and the additive are uniformly mixed to prepare a mixed solution of the photopolymer type holographic recording medium; Evenly distributing the mixed solution of the photopolymer holographic recording medium on the surface of the substrate, and irradiating the mixed solution under a first illumination condition to cause the film-forming resin to undergo a first polymerization reaction with the first photosensitive initiation system; The mixed solution is irradiated under a second illumination condition to cause a second polymerization reaction between the epoxy resin and the second photosensitive initiator system to produce a volume holographic grating; wherein the absorption spectrum of the first photosensitive initiator system is different from the absorption spectrum of the second photosensitive initiator system.

11. A volume holographic grating, characterized in that: The photopolymer holographic recording medium used in the volume holographic grating includes the photopolymer holographic recording medium described in any one of claims 1 to 9, or is prepared by the method for preparing a volume holographic grating described in claim 10.

12. A holographic device, characterized in that: The holographic device comprises the volume holographic grating of claim 11.

Images