Thianthrene monomer, holographic recording medium, preparation method and related device

Abstract

The invention discloses a thianthrene monomer, a holographic recording medium, a preparation method and a related device, the structural formula of the thianthrene monomer is shown as G1-G6, the refractive index of the thianthrene monomer is larger than 1.7 and smaller than 1.8, the diffraction efficiency can be remarkably improved, and further, the holographic recording medium can be applied to holographic recording. The thianthrene monomer with the structure is introduced into the photopolymer type holographic recording medium, so that the holographic recording medium with high sensitivity, high diffraction efficiency and high refractive index is obtained, and the invention further provides a preparation method of the holographic recording medium. The invention also provides a volume holographic grating, a holographic optical element and an optical device comprising the holographic recording medium.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of holographic material, and particularly relates to a thianthrene monomer, a holographic recording medium, a preparation method and a related device. BACKGROUND

[0002] Optical polymer with better performance usually requires that the film-forming resin has a lower refractive index, and the writing monomer has a higher refractive index, so as to increase the refractive index difference (Delta n) between the two.

[0003] However, the refractive index of the writing monomer currently available for the optical polymer is generally low (usually <1.6), resulting in a small refractive index difference (Delta n approximately equal to 0.1-0.2) between the writing monomer and the film-forming resin. Therefore, the refractive index modulation of the recording grating prepared thereby is low, which further leads to a reduced regulation ability of the grating to the incident light, a large light energy loss, a low diffraction efficiency of the optical device, and unclear imaging picture, and the like, and cannot meet the user demand. SUMMARY

[0004] Embodiments of the present application aim to provide a thianthrene monomer to solve the problem that the refractive index of the existing writing monomer is low, resulting in a small refractive index difference between the writing monomer and the film-forming resin, and the performance of the optical polymer is reduced.

[0005] In a first aspect, the present application provides a thianthrene monomer, the structural formula of which is shown in G1-G6:

[0006] In the formula, R1 represents hydrogen or methyl, n is a positive integer, and represents the number of methylene groups, n = 1-10.

[0007] As can be seen from the above technical solution, the thianthrene monomer provided in the first aspect of the present application comprises a thianthrene structure composed of two benzene rings and one sulfur-containing heterocycle, forming a large pi-conjugated system, which significantly enhances the absorption capacity of ultraviolet-visible light, and the presence of sulfur atoms increases the molecular polarizability, significantly improving the refractive index of the monomer, and the monomer is suitable for applications such as holographic storage which require high refractive index modulation.

[0008] In a second aspect, the present application provides a preparation method of the thianthrene monomer, and the preparation method comprises:

[0009] When the structural formula of the thianthrene monomer is G1, the preparation method comprises the following steps:

[0010] In step S101, the thianthrene is dissolved in a first solvent to obtain a first mixture, and the first mixture is subjected to a first treatment operation. A hydride reagent is added to the first mixture after the first treatment operation, to obtain a second mixture after reaction. The second mixture is subjected to a first treatment operation, and the second mixture after the first treatment operation is added dropwise with a compound M1, to obtain a third mixture after reaction. The third mixture is subjected to separation, to obtain a compound P1.

[0011] The first treatment operation at least includes a cooling operation and a stirring operation. The compound M1 is selected from one of N,N-dimethylformamide or piperidine-1-carboxaldehyde.

[0012] The compound P1 has the following structural formula:

[0013] In step S102, the second mixture after the first treatment operation is added dropwise with the compound P1, to obtain a fourth mixture after reaction. The fourth mixture is subjected to separation, to obtain a compound P2.

[0014] In step S103, the compound P2 and an acid-binding agent are dissolved in a second solvent, and a compound M2 is added for reaction, to obtain a fifth mixture after reaction. The fifth mixture is subjected to separation, to obtain the thianthrene monomer G1.

[0015] The compound M2 is acryloyl chloride or methacryloyl chloride. The compound P2 has the following structural formula:

[0016]

[0017] When the thianthrene monomer has a structural formula of G2 or G3, the following steps are included:

[0018] In step S201, the compound P2 is dissolved in a first solvent, and a hydride reagent is added for stirring for a first time duration, to obtain a sixth mixture. A compound M3 is added to the sixth mixture for reaction, to obtain a seventh mixture after reaction. The seventh mixture is subjected to separation, to obtain the thianthrene monomer G2 or G3.

[0019] The compound M3 is selected from a compound having any one of the following structural formulas:

[0020] When the thianthrene monomer has any one of structural formulas G4-G6, the following steps are included:

[0021] In step S301, a compound M4 is added to the sixth mixture for stirring for a certain time duration, to obtain a seventh mixture. The seventh mixture is subjected to separation, to obtain a compound P3.

[0022] Step S302, dissolving the compound P3 and an acid-binding agent in a second solvent, adding the compound M2 to react, obtaining an eighth mixture after reaction, and separating the eighth mixture to obtain the thianthrene monomer G4;

[0023] Step S303, dissolving the compound P3 in a first solvent, adding a hydrogenation agent to react, obtaining a ninth mixture after reaction, adding the compound M3 to the ninth mixture and stirring for a certain period of time to obtain a tenth mixture, and separating the tenth mixture to obtain the thianthrene monomer G5 or G6;

[0024] The compound M4 has the following structural formula: The compound P3 has the following structural formula:

[0025] n is a positive integer, and represents the number of methylene groups, n = 1-10.

[0026] It can be seen from the above technical solution that the preparation method of the thianthrene monomer provided in the second aspect of the present application has a simple synthesis method and high yield.

[0027] In a third aspect, the present application provides a photopolymer type holographic recording medium, the raw materials of which comprise the following components a)-component h):

[0028] Component a) is a compound having multiple isocyanate reactive functional groups;

[0029] Component b) is a polyisocyanate-based compound;

[0030] Component c) is a thianthrene monomer;

[0031] Component d) is a polymerizable monomer;

[0032] Component e) is a photosensitive initiation system;

[0033] Component f) is a chain transfer agent;

[0034] Component g) is an optional catalyst;

[0035] Component h) is an optional additive;

[0036] The thianthrene monomer is at least one of the aforementioned thianthrene monomers G1-G6.

[0037] From the above technical solution can be seen, the present application provides a photopolymer type holographic recording medium containing the above thianthrene monomer, by introducing the thianthrene monomer as one of the components of the writing monomer into the photopolymer type holographic recording medium, the writing monomer has higher refractive index, thereby effectively improving the refractive index difference between the recording monomer and the film forming resin, obtaining a high sensitivity, high diffraction efficiency holographic recording medium, specifically, the photopolymer holographic recording medium has a sensitivity greater than 100 cm / mJ, and the recording grating diffraction efficiency is greater than 95%, the exposure is less than 20 mJ / cm 2 and other excellent properties.

[0038] In a fourth aspect, the present application provides a preparation method of the above-mentioned photopolymer type holographic recording medium, comprising:

[0039] The compound having multiple isocyanate reactive functional groups, the polyisocyanate-based compound, the thianthrene monomer, the polymerizable monomer, the photosensitive initiation system, the chain transfer agent, the catalyst and the additive are weighed in a container, and fully stirred to dissolve to form a mixture solution;

[0040] The mixture solution is filtered using a filter membrane to obtain a first solution;

[0041] The first solution is coated on a substrate, and after drying, the photopolymer type holographic recording medium is obtained.

[0042] From the above technical solution can be seen, the present application provides a preparation method of the photopolymer type holographic recording medium, which is simple in operation and low in cost, can ensure uniform dispersion of each component, improve the light transmittance and refractive index modulation of the holographic recording medium, thereby enhancing the resolution and diffraction efficiency of the hologram. In addition, the filtering step can effectively remove impurities, reduce light scattering, and improve the storage stability and imaging quality of the holographic medium.

[0043] In a fifth aspect, the present application provides a volume holographic recording grating, wherein the photopolymer type holographic recording medium used by the volume holographic recording grating comprises the photopolymer type holographic recording medium as described above.

[0044] In a sixth aspect, the present application provides a holographic optical element, wherein the raw material of the holographic optical element comprises the photopolymer type holographic recording medium as described above.

[0045] In a seventh aspect, the present application provides an optical device comprising the holographic optical element as described above.

[0046] From the above solution, the present application also provides related devices prepared using the above-mentioned photopolymer holographic recording medium, and the photopolymer holographic recording medium has a sensitivity greater than 100 cm / mJ and an exposure less than 20 mJ / cm2 and the recording grating diffraction efficiency is greater than 95%, etc.

[0047] Further, based on the sensitivity being greater than 100 cm / mJ, therefore, only a very low exposure energy is required to form a stable grating, which can shorten the exposure time, reduce the laser power requirement, improve the recording speed and reduce the energy consumption efficiency, and is suitable for dynamic recording and low-power equipment. Based on the exposure amount being less than 20 mJ / cm 2 , therefore, a small amount of light energy can complete the curing and photopolymerization, avoid material deformation caused by high-energy exposure, and at the same time, low-energy exposure can also inhibit light scattering and improve the precision of micro-nano structures. Based on the diffraction efficiency being greater than 95%, it means that almost all of the incident light energy is diffracted by the grating to the target direction, thereby reducing the loss of light energy and making the imaging picture clearer.

[0048] Therefore, the target device (such as a volume holographic recording grating, an optical element and an optical device) prepared by using the photopolymer holographic recording medium has the optical performance of fast recording speed, low energy consumption efficiency and clear imaging, etc. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 Exposure characteristic curves of the photopolymer holographic recording medium 7-1 to 7-6 in Example 7 of the present application are shown;

[0050] Figure 2 Exposure characteristic curves of the ordinary photopolymer holographic recording medium in the comparative example of the present application are shown. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0052] It should be understood that, when used in the specification and the appended claims, the terms “comprise” and “include” indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or collections thereof.

[0053] It should also 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. As used in the specification and the appended claims of the present application, unless otherwise clearly indicated by the context, the singular forms “a”, “an” and “the” are intended to include the plural forms.

[0054] It should be further understood that the term "and / or" as used in the specification and in the claims, if any, means any one of the associated listed items, as well as all possible combinations of the items, and includes the items.

[0055] Some embodiments of the present application will be described in detail with reference to the drawings. The following embodiments and features of the embodiments can be combined with each other without conflict.

[0056] It should be understood that the photopolymer type holographic recording medium material for holographic recording is to realize holographic recording by using light to polymerize the writing monomer and form a refractive index modulated phase type holographic grating with the film-forming resin. The monomer in the coherent bright area is polymerized and consumed, and the concentration is reduced, while the monomer in the coherent dark area hardly reacts. The difference in monomer concentration between the bright area and the dark area promotes the monomer in the dark area to migrate to the bright area, and at the same time, the film-forming resin in the bright area is squeezed to the dark area. Finally, the refractive index of the bright area approaches the refractive index of the polymer, and the refractive index of the dark area approaches the refractive index of the film-forming resin, thereby forming a phase type volume holographic grating with refractive index modulation.

[0057] It should be noted that the photopolymer type holographic recording medium with better performance generally requires the film-forming resin to have a lower refractive index and the writing monomer to have a higher refractive index, so as to increase the refractive index difference (Δn) between the two.

[0058] It can be understood that increasing the refractive index difference between the writing monomer and the film-forming resin helps to improve the grating's regulation ability to incident light, reduce light energy loss, and further improve the diffraction efficiency of the optical device.

[0059] However, the refractive index of the writing monomer available for the photopolymer is generally low (usually <1.6), which results in a small refractive index difference (Δn≈0.1-0.2) between the writing monomer and the film-forming resin, limiting the performance improvement of the photopolymer.

[0060] Based on this, the present application provides a thianthrene monomer as a component of the writing monomer, which has a structure as shown in any one of G1-G6:

[0061] Wherein, R1 represents hydrogen or methyl, n is a positive integer, and represents the number of methylene groups, n=1-10.

[0062] In the embodiment, the thianthrene monomer has a structure composed of two benzene rings and one sulfur-containing heterocycle, forming a larger π-conjugated system, significantly enhancing the absorption capacity of ultraviolet-visible light, and the presence of sulfur atoms increases the molecular polarizability, significantly improving the refractive index of the monomer, so that the entire monomer molecule presents a very high refractive index, which is greater than 1.7 and less than 1.8, which can effectively match common photosensitive resin systems, reduce light scattering loss during holographic recording, and improve diffraction efficiency. At the same time, the high refractive index helps to enhance the optical anisotropy of the material, optimizing the resolution and storage capacity of the hologram.

[0063] The application also provides a preparation method of the thianthrene monomer, and the preparation method comprises the following steps:

[0064] When the structural formula of the thianthrene monomer is G1, the method comprises the following steps:

[0065] In step S101, the thianthrene is dissolved in a first solvent to obtain a first mixture, and the first mixture is subjected to a first treatment operation. A hydride reagent is added to the first mixture after the first treatment operation, to obtain a second mixture after reaction. The second mixture is subjected to a first treatment operation, and a compound M1 is added dropwise to the second mixture after the first treatment operation, to obtain a third mixture after reaction. The third mixture is separated to obtain the compound P1.

[0066] The first treatment operation at least comprises a cooling operation and a stirring operation, and the compound M1 is selected from one of N,N-dimethylformamide or piperidine-1-carbaldehyde. The structural formula of the compound P1 is as follows:

[0067] It can be understood that in step S101, the hydride reagent is used to abstract the proton hydrogen at the adjacent position of the sulfur atom in the thianthrene, so that the thianthrene is activated to form an intermediate I. The intermediate I further attacks the carbonyl carbon in the compound M1, and after hydrolysis, thianthrene-2-formaldehyde (i.e. the compound P1) is further generated.

[0068] The first treatment operation at least comprises a cooling operation and a stirring operation, and the cooling operation and the stirring operation can be performed simultaneously or staggered, for example, the stirring operation and the cooling operation can be performed simultaneously, or the stirring operation can be performed for a period of time and then the cooling operation is performed. The application does not make any limitation.

[0069] It can be understood that the hydride reagent includes but is not limited to organic metal bases, metal amine compounds, metal alkoxides, metal hydrides, inorganic bases and organic bases.

[0070] The organic metal base includes, but is not limited to, alkyl lithium reagent, aryl lithium reagent and amino lithium reagent. Generally, when the organic metal base and metal amine compound are used, the reaction needs to be controlled in anhydrous and anaerobic conditions, and generally needs to be added into the reaction system in batches at -78℃. Further, the alkyl lithium reagent includes at least n-butyllithium and tert-butyllithium, the aryl lithium reagent includes at least phenyllithium, the amino lithium reagent includes at least diisopropylaminolithium and hexamethyldisilylaminolithium, and the metal amine compound includes, but is not limited to, sodium amide, potassium amide, sodium bis(trimethylsilyl)amide. The metal alkoxide includes, but is not limited to, sodium methoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide, the metal hydride includes, but is not limited to, sodium hydride and potassium hydride, the inorganic base includes, but is not limited to, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate and potassium phosphate, and the organic base includes, but is not limited to, triethylamine, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene and tetramethylsilane triflate.

[0071] It should be further understood that when the deprotonation agent is used, it needs to be determined according to different types of deprotonation agent, the properties of the reaction substrate and other factors whether the reaction needs to be carried out in an inert environment, for example, protected by inert gas, which includes, but is not limited to, nitrogen and argon, in other words, the skilled in the art can carry out inert protection according to actual needs, which is not limited in the present application.

[0072] It should be noted that the deprotonation reaction generally needs to be carried out at low temperature (-80℃-0℃), and the selection of the reaction temperature is related to the selection of the deprotonation agent, the stability and activity of the reaction substrate, and the melting point of the reaction solvent. After the deprotonation reaction is completed, it can be selected according to actual needs (for example, the activity of the reaction substrate, the reaction rate, etc.) whether to increase the temperature. Specifically, when the deprotonation agent is an organic metal base and a metal amine compound (for example, n-butyllithium), the deprotonation reaction generally needs to be carried out at -30-80℃ and in an inert environment, so as to obtain a better reaction effect, inhibit the generation of side reactions and improve the regioselectivity of the reaction. When the deprotonation agent is a metal alkoxide and a metal hydride (for example, sodium hydride and sodium methoxide), the deprotonation reaction is generally carried out at 0℃ (i.e. under ice bath), and the deprotonation reaction time is generally 0.5h-10h. It can be understood that the deprotonation reaction time is related to the amount of the deprotonation agent and the activity of the reaction substrate, which is not limited in the present application.

[0073] It should be further noted that the deprotonation agent needs to be added into the reaction system in batches and slowly, so as to avoid violent reaction and cause material spraying and personal injury.

[0074] It can be further understood that the first mixture includes at least thianthrene, the second mixture includes at least the intermediate I formed after the deprotonation of thianthrene and the deprotonation agent, and the third mixture includes at least the compound M1 and the compound P1.

[0075] For example, 1 equivalent of thianthrene is dissolved in anhydrous tetrahydrofuran solvent, and the temperature is lowered to -30 to -80°C, then 1 to 1.5 equivalents of n-butyllithium solution is added dropwise into the reaction system, after the dropwise addition is completed, the reaction system is slowly warmed to room temperature and stirred for 0.5 to 3 hours. Then the temperature of the reaction system is lowered to -30 to -80°C again, and 1 to 1.5 equivalents of N,N-dimethylformamide or piperidine-1-carboxaldehyde is added dropwise, and the reaction is stirred for 1 to 5 hours. After the reaction is completed, sufficient water is added to the reaction system to quench the reaction, and the organic phase is extracted with dichloromethane, and the obtained organic phase is washed with water three times, and the organic phase is dried with anhydrous sodium sulfate, and the excess solvent is removed by rotary evaporation, and column chromatography is used to separate to obtain compound P1.

[0076] In some specific examples, in step S101, the molar ratio of thianthrene to the hydrogenation agent is 1:(1-1.5), and the molar ratio of thianthrene to compound M1 is 1:(1-1.5).

[0077] Typically but not limitedly, for example, the molar ratio of thianthrene to the hydrogenation agent can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, and the molar ratio of thianthrene to compound M1 can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5.

[0078] In addition, the first solvent includes but is not limited to one or more of petroleum ether, dichloromethane, trichloromethane, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, 1,4-dioxane, dimethoxyethane, N,N-dimethylformamide or dimethyl sulfoxide.

[0079] It can be understood that the first solvent makes the reaction substrate fully dissolved in the reaction system to form a homogeneous reaction system, thereby improving the reaction efficiency. It is worth noting that the first solvent should be selected to be a solvent that does not react with the hydrogenation agent (such as n-butyllithium, sodium hydride, etc.) to avoid violent reaction, resulting in quenching or explosion.

[0080] It should be noted that the above-mentioned solvent is only an example, and the solvent that can be used in the present application is not limited thereto.

[0081] In step S102, compound P1 is added dropwise to the second mixture after the first treatment operation is completed, and a fourth mixture after reaction is obtained, and the fourth mixture is separated to obtain compound P2.

[0082] The structural formula of compound P2 is as follows:

[0083] It can be understood that, in step S102, the compound P1 is added dropwise to the second mixture in which the intermediate I (formed after the deprotonation of thianthrene) is generated to further obtain the compound P2. The compound P1 is added dropwise to the second mixture at -30 to -80°C, and the reaction has a better effect.

[0084] For example, 1 eq. of thianthrene is dissolved in anhydrous tetrahydrofuran solvent under a nitrogen environment. Then, 1 to 1.5 eq. of n-butyllithium solution is added dropwise to the reaction system at -30 to -80°C. After the dropwise addition is completed, the reaction system is slowly warmed to room temperature and continues to be stirred for 0.5 to 3 hours. Subsequently, 1 to 1.5 eq. of the compound P1 is added dropwise to the reaction system at -30 to -80°C. After the reaction is completed, a sufficient amount of H2O is added to the reaction system to quench the reaction, and the organic phase is extracted with dichloromethane. The obtained organic phase is washed with water three times and dried with anhydrous sodium sulfate. The excess solvent is removed by rotary evaporation, and the compound P2 is separated by column chromatography.

[0085] It can be understood that the second mixture at least includes the intermediate I (formed after the deprotonation of thianthrene), and the fourth mixture at least includes the compound P1 and the compound P2.

[0086] In some embodiments, the molar ratio of thianthrene (or the intermediate I) to the compound P1 is 1:(1 to 1.5). Typically but not limitedly, for example, the molar ratio of thianthrene (or the intermediate I) to the compound P1 can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, or 1:1.5.

[0087] It can be understood that the molar amount of the intermediate I obtained in step S102 can be calculated by the amount of thianthrene used in step S101.

[0088] In step S103, the compound P2 and the acid-binding agent are dissolved in a second solvent, and the compound M2 is added to react to obtain a fifth mixture. The thianthrene monomer G1 is obtained by separating the fifth mixture, and the compound M2 is acryloyl chloride or methacryloyl chloride.

[0089] It can be understood that, in some specific examples, the reaction is usually controlled to be carried out at 0°C (i.e., under ice bath). That is, the compound M2 is added dropwise to the mixed solution of the compound P2 and the acid-binding agent at 0°C to avoid local overheating or high concentration to cause side reactions. The reaction time is usually 0.5 to 3 hours, which has a better reaction effect.

[0090] It can also be understood that the fifth mixture at least includes the compound P2, the acid-binding agent, the compound M2, and the corresponding thianthrene monomer G1.

[0091] Exemplarily, compound P2 and triethylamine are dissolved in dichloromethane under ice bath, after stirring for 10 min, acryloyl chloride or methacryloyl chloride is added dropwise into the mixed solution of compound P2 and triethylamine at 0°C. After the reaction is completed, dilute hydrochloric acid is added dropwise to remove excess acryloyl chloride or methacryloyl chloride, and the organic phase is sequentially washed with saturated NaCl solution, saturated NaHCO3 solution and deionized water. After drying over anhydrous sodium sulfate, the excess solvent is removed by rotary evaporation, and column chromatography is used to separate to obtain the thianthrene monomer G1.

[0092] In addition, the acid-binding agent includes, but is not limited to, one or more of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium acetate, sodium hydroxide, potassium hydroxide, calcium oxide and potassium tert-butoxide.

[0093] The second solvent includes, but is not limited to, one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide. When the second solvent is one of dichloromethane, chloroform or ethyl acetate, the reaction has a better effect.

[0094] It should be further understood that, since compound M2 (i.e. acryloyl chloride or methacryloyl chloride) is a highly active acylating agent, side reactions are prone to occur, resulting in a decrease in the amount actually participating in the target reaction. Therefore, it is generally necessary to use an excess amount to compensate for the consumption of side reactions to ensure that sufficient acyl chloride reacts with the reaction substrate. In addition, since the acid-binding agent is required to neutralize the hydrochloric acid generated in the reaction to prevent the decomposition of the reaction substrate or product, the acid-binding agent also generally needs to be used in excess. Specifically, in some examples, the molar ratio of compound P2, compound M2 and the acid-binding agent is 1:(1-3):(1-4).

[0095] Typically but not limitedly, the molar ratio of compound P2, compound M2 and the acid-binding agent may be, for example, 1:3:4, 1:3:3, 1:2:3, 1:2.5:3.5, 1:2:4, etc.

[0096] When the structural formula of the thianthrene monomer is G2 or G3, the following steps are included:

[0097] Step S201, compound P2 is dissolved in a first solvent, and a hydrogen-abstracting agent is added and stirred for a first time period to obtain a sixth mixture. Compound M3 is added to the sixth mixture to react, and a seventh mixture after reaction is obtained. The seventh mixture is separated to obtain the thianthrene monomer G2 or G3.

[0098] Compound M3 is selected from a compound represented by any one of the following structural formulas:

[0099] It can be understood that, in step S201, after the hydroxyl hydrogen of compound P2 is removed by the hydride reagent, an alkoxy negative ion intermediate II is generated, and the intermediate II further attacks the carbonium ion in compound M3, and finally the thianthrene monomer G2 or G3 is obtained. Among them, the first time length is usually 0.5-10h, and it can be understood that the reaction time is usually related to the amount of reaction substrate and the activity of the reaction substrate.

[0100] It can also be understood that the sixth mixture at least includes the alkoxy negative ion intermediate II, and the seventh mixture at least includes the corresponding thianthrene monomer G2 or G3 and compound M3.

[0101] For example, compound P2 is dissolved in tetrahydrofuran, and sodium hydride is slowly added in batches at 0°C (i.e. under ice bath), and stirred for 0.5-10h, and then 3-bromopropene is added dropwise after the reaction is completed, and stirring is continued for 0.5-10h after the addition is completed. After the reaction is completed, the reaction is quenched by slowly adding dilute hydrochloric acid, and the excess solvent is removed by rotary evaporation, and column chromatography is used to separate to obtain the thianthrene monomer G2.

[0102] In some embodiments, the molar ratio of compound P2 to hydride reagent is 1:(1-1.5), and the molar ratio of compound P2 to compound M3 is 1:(1-2).

[0103] Typically but not limitedly, for example, the molar ratio of compound P2 to hydride reagent can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc. The molar ratio of compound P2 to compound M3 can be 1:1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:2, etc.

[0104] When the structural formula of the thianthrene monomer is any one of G4-G6, the following steps are included:

[0105] Step S301, compound M4 is added to the sixth mixture and stirred for a certain time to obtain the seventh mixture, and compound P3 is obtained by separating the seventh mixture. The structural formula of the compound M4 is: The structural formula of compound P3 is:

[0106] n is a positive integer and represents the number of methylene groups, n=1-10.

[0107] It can be understood that, in step S301, the alkoxy negative ion intermediate II generated from compound P2 further reacts with compound M4, and the seventh mixture at least includes sodium hydride, compound M4 and compound P3.

[0108] Therefore, in some embodiments, the molar ratio of compound P2 (intermediate II) to compound M4 is 1:(1-1.5) for better reaction effect.

[0109] For example, compound P2 is dissolved in tetrahydrofuran, and sodium hydride is slowly added in batches at 0°C (i.e. under ice bath), and the reaction is stirred for 0.5-10 hours. After the reaction is completed, compound M4 is added dropwise, and stirring is continued for 0.5-10 hours after the addition is completed. After the reaction is completed, dilute hydrochloric acid is slowly added to quench the reaction, and excess solvent is removed by rotary evaporation. Column chromatography is used to separate compound P3.

[0110] In step S302, compound P3 is dissolved in a second solvent with an acid binding agent, and compound M2 is added for reaction to obtain an eighth mixture. The eighth mixture is separated to obtain thianthrene monomer G4.

[0111] It can be understood that the eighth mixture at least includes the acid binding agent, compound M2 and thianthrene monomer G4. In some specific examples, the molar ratio of compound P3, compound M2 and the acid binding agent is 1:(1-3):(1-4), and the reaction is carried out at 0°C to have a better reaction effect.

[0112] It can also be understood that step S302 has the same reaction principle and applicable conditions as step S103, except that the reaction substrate is different (i.e. compound P3). Therefore, for related content, please refer to step S103, which will not be repeated here.

[0113] In step S303, compound P3 is dissolved in a first solvent with a deprotonating agent for reaction to obtain a ninth mixture. Compound M3 is added to the ninth mixture and stirred for a certain period of time to obtain a tenth mixture. The tenth mixture is separated to obtain thianthrene monomer G5 or G6.

[0114] It can be understood that in step S303, compound P3 first forms alkoxy negative ion intermediate III under the action of the deprotonating agent. Intermediate III further reacts with compound M3 to obtain thianthrene monomer G5 or G6. Therefore, the ninth mixture at least includes compound P3, the deprotonating agent and alkoxy negative ion intermediate III, and the tenth mixture at least includes compound M3 and thianthrene monomer G5 or G6.

[0115] Since the deprotonating agent is used for deprotonation reaction, the reaction is usually carried out at low temperature for deprotonation. After the deprotonation reaction is completed, the temperature can be selected as needed. For specific reaction conditions, please refer to the foregoing corresponding content (including the selection of the deprotonating agent), which will not be repeated here.

[0116] Exemplarily, 1 equivalent of compound P3 is dissolved in tetrahydrofuran, 1-1.5 equivalents of sodium hydride is slowly added under ice bath (0°C), the reaction is stirred for 0.5-10 hours, then 1-1.5 equivalents of compound M3 is added dropwise, after the addition is completed, the stirring is continued for 0.5-10 hours. After the reaction is completed, dilute hydrochloric acid is slowly added to the reaction system to quench the reaction, the excess solvent is removed by rotary evaporation, and column chromatography is used to separate to obtain thianthrene monomer G5 or G6.

[0117] In some embodiments, the molar ratio of compound P3 to the hydrogenation agent is 1:(1-1.5), and the molar ratio of compound P3 to compound M3 is 1:(1-2).

[0118] Typically but not limitedly, for example, the molar ratio of compound P3 to the hydrogenation agent can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc. The molar ratio of compound P3 to compound M3 can be 1:1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:2, etc.

[0119] In the present embodiment, the thianthrene monomer synthesis method is simple, and the thianthrene monomer prepared by the preparation method has high yield.

[0120] The present application also provides a photopolymer type holographic recording medium, which comprises a writing monomer, and the writing monomer comprises a (meth)acrylate monomer and a polymerizable monomer.

[0121] Further, in some embodiments, the raw material of the photopolymer type holographic recording medium comprises components a)-h) as follows:

[0122] Component a) a compound having multiple isocyanate-reactive functional groups,

[0123] Component b) a polyisocyanate-based compound,

[0124] Component c) at least one of the aforementioned thianthrene monomers G1-G6,

[0125] Component d) a polymerizable monomer,

[0126] Component e) a photosensitive initiation system,

[0127] Component f) a chain transfer agent,

[0128] Component g) an optional catalyst,

[0129] Component h) an optional additive,

[0130] The compound having multiple isocyanate-reactive functional groups and the polyisocyanate-based compound form a film-forming resin.

[0131] In the present embodiment, thianthrene monomers with high refractive index are used as the component of the writing monomer, so that the writing monomer and the film-forming resin have a greater refractive index difference, to form a photopolymer type holographic recording material with high sensitivity and high diffraction efficiency, and other excellent properties. Specifically, in some examples, the photopolymer type holographic recording medium has a photosensitive sensitivity greater than 100 cm / mJ, an exposure amount less than 20 mJ / cm 2 and a recording grating diffraction efficiency greater than 95%, and other excellent properties.

[0132] More specifically, in some examples, the composition and content of the photopolymer type holographic recording medium are as follows:

[0133] Component a) compound with multiple isocyanate reactive functional groups 10-50 wt%,

[0134] Component b) polyisocyanate-based compound 10-50 wt%,

[0135] Component c) thianthrene monomer 1-30 wt%,

[0136] Component d) polymerizable monomer 10-40 wt%,

[0137] Component e) photosensitive initiation system 0.1-3 wt%,

[0138] Component f) chain transfer agent 0.1-3 wt%,

[0139] Component g) catalyst 0.1-5 wt%,

[0140] Component h) additive 0.1-10 wt%.

[0141] In the present embodiment, by reasonably controlling the composition and proportion of the components of the photopolymer type holographic recording medium, the components can fully synergize, and the holographic performance of the final photopolymer type holographic recording medium will not be affected by too much or too little of a certain component. The overall holographic performance of the final photopolymer type holographic recording medium is good, to achieve high resolution, high diffraction efficiency, and long-term stability.

[0142] In some embodiments, the content of thianthrene monomers in the entire photopolymer type holographic recording medium is 0.1-30 wt%.

[0143] Typically but not limited to, the content of thianthrene monomers in the entire photopolymer type holographic recording medium can be 0.1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, or a range value composed of any two numerical values.

[0144] In the present embodiment, the content of the thianthrene monomer is in the range of 0.1-30wt%, which ensures that sufficient active monomers are provided to participate in photopolymerization, so that the formed writing monomers can have sufficient concentration to achieve the concentration difference between the bright area and the dark area after the reaction under light.

[0145] In some embodiments, the isocyanate-reactive functional group is a hydroxyl group. The compound having multiple isocyanate-reactive functional groups includes a compound having a refractive index less than or equal to a first refractive index threshold and having two or more hydroxyl functional groups, the first refractive index threshold being any value between 1.5 and 1.55. Alternatively, the polyisocyanate-based compound includes a compound having a refractive index less than or equal to a second refractive index threshold and having two or more isocyanate groups, the second refractive index threshold being any value between 1.5 and 1.55.

[0146] Typically but not limited to, the first refractive index threshold can be 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, or any value between any two of the values, and the second refractive index threshold can be 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, or any value between any two of the values.

[0147] In the present embodiment, the compound having multiple isocyanate-reactive functional groups with a refractive index less than or equal to 1.5-1.55 and the polyisocyanate-based compound with a refractive index less than or equal to 1.5-1.55 form a low-refractive-index film-forming resin, and the low-refractive-index film-forming resin and the high-refractive-index recording monomer (i.e., the thianthrene monomer described above has a refractive index of 1.7-1.8) form a significant refractive index difference (Δn≥0.1), which can enhance the diffraction efficiency of the holographic grating while avoiding the increase in background noise due to the high refractive index of the substrate itself.

[0148] In some embodiments, the isocyanate-reactive functional group is a hydroxyl group, and the molar ratio of the hydroxyl group to the isocyanate functional group is 1:1, i.e., the molar ratio of the hydroxyl group in the compound having multiple isocyanate-reactive functional groups in component a) to the isocyanate functional group in the polyisocyanate-based compound in component b) in the film-forming resin forming the photopolymer type holographic recording medium is 1:1.

[0149] Further, in some examples, the compound having multiple isocyanate-reactive functional groups can be one or more of tetraethylene glycol, trimethylol ethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200-2000, polycarbonate polyol, and polyether polyol, but is not limited thereto.

[0150] Polyisocyanate-based compounds include, but are not limited to, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)- triyl)tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate.

[0151] In some examples, the polymerizable monomer is selected from at least one of an alkenyl naphthalene compound, an alkenyl anthracene compound, an alkenyl benzene compound, an acrylic compound, a methacrylic compound, an acrylate compound, a methacrylate compound, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazole, N-vinylindole, N-vinylpyrrolidone, trans-N-3-alkynylbutenylcarbazole.

[0152] In specific examples, the alkenyl benzene compound includes, but is not limited to, styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene.

[0153] Exemplary methacrylic compounds can be methacrylic acid and derivatives thereof. For example, the methacrylate compound can be selected from 2-phenoxyethyl methacrylate, benzyl methacrylate, p-bromophenyl methacrylate, p-chlorophenyl methacrylate, 2,4,6-trichlorophenyl methacrylate, pentabromophenyl methacrylate, pentachlorophenyl methacrylate, phenoxyethyl methacrylate, phenoxyethoxyethyl methacrylate, 1,4-di(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate, and the like.

[0154] In specific examples, the acrylate compound includes, but is not limited to, pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-di(2-thionaphthyl) 2-butyl acrylate, phenoxyethoxyethyl acrylate, bisphenol A diacrylate, tetrabromobisphenol A diacrylate, 2-phenoxyethyl acrylate, benzyl acrylate, p-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate, p-bromophenyl acrylate, 2,4,6-tribromophenyl acrylate, propane-2,2-diyl bis[(2,6-dibromo-4,1-phenylene)oxy(2-{[3,3,3-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate.

[0155] In specific examples, the vinyl anthracene compound can be selected from 2-vinyl anthracene, 9-vinyl anthracene, and the like.

[0156] In specific examples, the vinyl naphthalene compound can be selected from 1-vinyl naphthalene, 2-vinyl naphthalene, and the like.

[0157] In some embodiments, the photosensitive initiation system is composed of a photosensitizer and a photoinitiator in cooperation, and a wide-spectrum response visible light initiation system is constructed through the cooperation of the two. The photosensitizer can selectively absorb laser energy of a specific wavelength (such as 532 nm or 633 nm) and activate the photoinitiator through an energy transfer mechanism, thereby significantly expanding the photosensitive wavelength range of the system, and thus different wide-band responses can be achieved by adjusting the type of photosensitizer. Under the irradiation of light in a specific wavelength range, the photosensitizer in the photosensitive initiation system is activated by the corresponding light, and absorbs light energy, which is then transferred to the photoinitiator, so that the photoinitiator can be activated under more frequency light radiation. The activated photoinitiator efficiently produces active free radicals, rapidly initiates monomer polymerization reaction, realizes the construction of holographic grating structure, improves the photosensitive sensitivity of the photopolymer type holographic recording medium, and enhances the compatibility with different wavelength lasers, providing a more flexible light source selection scheme for holographic storage.

[0158] It can be understood that when a photoinitiator with an adaptive wavelength is selected in the raw material of the photopolymer type holographic recording medium, the photosensitizer can not be added. For example, when the photoinitiator is titanium complex (Irgacure 784), the photosensitizer can not be added. It is an orange solid photoinitiator with extremely high reactivity, which can initiate the polymerization reaction of unsaturated resin under the action of visible light or ultraviolet light.

[0159] In some examples, the mass ratio of the photosensitizer and the photoinitiator is (0.001-1):(0.1-3). Typically but not limitedly, the mass ratio of the photosensitizer and the photoinitiator can be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, or 1:3, etc.

[0160] By adjusting the ratio of the photosensitizer and the photoinitiator within the above range, the energy transfer efficiency of the photosensitizer and the free radical yield of the photoinitiator can be balanced, the energy waste caused by excessive photosensitizer or the side reactions caused by excessive initiator can be avoided, the polymerization reaction can be efficiently started, and the reaction speed of the polymerization reaction can be controlled within a reasonable range, so that the speed of grating formation can be controlled within a certain range, the light transmittance of the photopolymer type holographic recording medium can be ensured, and excellent diffraction efficiency can be obtained.

[0161] wherein the photosensitizer is a dye with high electron transfer efficiency under light, including but not limited to cyanine dye, fluorescein dye, coumarin ketone dye, nitrogen-containing aromatic heterocyclic compound, aromatic amine compound, benzylidene cycloalkanone compound.

[0162] Exemplarily, the photosensitizer can be one or more of neomethylene blue, thionine, basic yellow, chlorinated pinacyanol, rhodamine 6G, malachite cyanine, 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, brilliant green, pyri11lium I, azure A, crystal violet white nitrile, malachite green white nitrile, etc.

[0163] The photoinitiator is an initiator capable of being activated by photochemical radiation and initiating polymerization of the corresponding polymerizable group, including but not limited to aromatic ketone compounds, benzoin and its derivatives, benzil ketone, acyl phosphine oxide, aryl borate ammonium, chromium salt, aryl diazonium salt, onium salt, organic metal compound.

[0164] Specifically, the photoinitiator can be one or more of benzophenone, alkyl benzophenone, 4,4'-bis(dimethylamino) benzophenone, anthrone and halogenated benzophenone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, bisacyl phosphine oxide, phenyl dihydroxyacetate, camphorquinone, a-aminoalkyl phenone, a,a-dialkoxyacetophenone, a-hydroxyalkyl phenone, tetrabutylammonium triphenylhexyl borate, tetrabutylammonium tri-(3-fluorophenyl) hexyl borate, tetrabutylammonium tri-(3-chloro-4-methylphenyl) hexyl borate, ferrocenyl compound, iodonium salt, sulfonium salt, hexaaryl bisimidazole, etc.

[0165] As a chain transfer agent, the chain transfer agent can control the polymer chain length within a certain reasonable range, effectively prevent the polymerization degree from being too high, and ensure that the final holographic recording medium has the required optical performance and diffraction efficiency.

[0166] In some embodiments, the chain transfer agent can be a thiol compound, for example, can be one or more of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, etc., but not limited thereto.

[0167] It can be understood that the molecular weight of the thianthrene monomer after polymerization with the polymerizable monomer can be controlled by using the amount of the photosensitive initiator system and the chain transfer agent, and the amount of use thereof can be appropriately adjusted according to the type thereof.

[0168] As a catalyst, the catalyst can effectively increase the reaction rate of the related components, increase the consumption rate of the related components after exposure, and thus quickly form the concentration difference of the monomers of the bright area and the dark area, so as to realize the phase-type volume holographic grating of refractive index modulation.

[0169] In some embodiments, the catalyst can be tertiary amine catalysts and organometallic catalysts, such as triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropylenediamine, N,N-bis(dimethylaminopropyl) isopropanolamine, dibutyl tin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts, but not limited thereto.

[0170] For example, as the defoaming agent, the defoaming agent includes silicone defoaming agents and non-silicone polymer defoaming agents, which are mainly used to eliminate or inhibit the bubbles generated in the material preparation and photocuring process to ensure the high resolution, high diffraction efficiency, and structural uniformity of the hologram.

[0171] Specifically, the defoaming agent can be selected from BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, BYK-1760 produced by BYK Company, DC65, AFE-7820 produced by Dow Corning Company, or any proportion mixture of these defoaming agents, but not limited thereto. Among them, the BYK series of defoaming agents have excellent defoaming performance, good compatibility with other components, and good dispersibility. BYK-011, BYK-012, BYK-014, and BYK-051N are non-silicone polymer defoaming agents. DC65 is a water-based ink, which has fast drying, good printing effect, and is not easy to fall off. AFE-7820 has high-efficiency defoaming performance. The content of the defoaming agent in the photopolymer type holographic recording medium is less than or equal to 3wt%. Typically but not limitedly, the content of the defoaming agent in the photopolymer type holographic recording medium can be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, etc.

[0172] In a specific example, the leveling agent is a silicone surface aid, and the content of the leveling agent in the photopolymer type holographic recording medium is less than or equal to 3wt%. Typically but not limitedly, the content of the leveling agent in the photopolymer type holographic recording medium can be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, etc.

[0173] The leveling agent can be selected from the BYK series of leveling agents produced by BYK Company, such as BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566, or any proportion mixture of these surface auxiliaries, but not limited to.

[0174] As a plasticizer, the plasticizer weakens the intermolecular stress by inserting between the polymer molecular chains, increases the mobility of the molecular chains, and reduces the crystallinity, thereby increasing the plasticity of the polymer. In specific examples, the plasticizer can be selected from one or more of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate, but not limited to. The content of the plasticizer in the photopolymer type holographic recording medium is less than or equal to 3wt%. Typically but not limited to, the content of the plasticizer in the photopolymer type holographic recording medium can be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, etc.

[0175] It can be understood that the residual moisture in the photopolymer type holographic recording medium can cause the hydrolytic failure of the photosensitive initiation system (such as a photoinitiator), reduce the photosensitivity, and at the same time, the moisture can have a side reaction with the isocyanate group (-NCO) involved in forming the film-forming resin, generate urea bonds and release CO2, resulting in bubbles or microstructure defects. Therefore, by adding a water scavenger, maintaining the system dry through the water scavenger, the efficiency of the photopolymerization reaction can be ensured, thereby improving the uniformity of the holographic grating and the storage life of the medium.

[0176] As a water scavenger, the water scavenger includes but is not limited to p-methylbenzenesulfonylisocyanate, triethyl orthoformate, CUWR-WB20 water scavenger produced by Guangzhou Yourun Synthetic Material Co., Ltd., ALT-201 water scavenger produced by Anxiang Ailite Chemical Co., Ltd., PCCI water scavenger produced by Shanghai Lur Chemical Co., Ltd., etc.

[0177] In some embodiments, the content of the water scavenger in the photopolymer type holographic recording medium is less than or equal to 3wt%. Typically but not limited to, the content of the water scavenger in the photopolymer type holographic recording medium can be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, etc.

[0178] The present application also provides a preparation method of the photopolymer type holographic recording medium, which includes:

[0179] The components of component a), component b), component c), component d), component e), component f), component g) and component h) are weighed into a container and stirred sufficiently to dissolve to form a mixture solution. The mixture solution is filtered using a filter membrane to obtain a first solution, which is coated onto a substrate to obtain the photopolymer type holographic recording medium after drying.

[0180] For example, the drying is performed in a dark room with humidity of 10% to 85% and temperature of 20°C to 50°C.

[0181] Further, the application provides a volume holographic recording grating, and the photopolymer type holographic recording medium used by the volume holographic grating includes the photopolymer type holographic recording medium described in any of the foregoing embodiments.

[0182] It can be understood that the volume holographic recording grating is prepared by exposing the photopolymer type holographic recording medium using the interference principle of light, and thus the holographic optical performance of the photopolymer type holographic recording medium determines the quality of the volume holographic recording grating.

[0183] Therefore, the photopolymer type holographic recording medium provided by the application has excellent performance, such as a sensitivity greater than 100 cm / mJ, an exposure amount less than 20 mJ / cm 2 , and a recording grating diffraction efficiency greater than 95%.

[0184] It can be understood that the sensitivity greater than 100 cm / mJ indicates that only a very low exposure energy is required to form a stable grating, which can shorten the exposure time, reduce the laser power requirement, improve the recording speed and reduce the energy consumption efficiency, and is suitable for dynamic recording and low-power equipment. Based on the exposure amount less than 20 mJ / cm 2 , only a small amount of light energy is required to complete the curing and photopolymerization, which avoids material deformation caused by high-energy exposure, and the low-energy exposure also inhibits light scattering and improves the precision of the micro-nano structure. Based on the diffraction efficiency greater than 95%, it indicates that almost all the incident light energy is diffracted to the target direction by the grating, so as to reduce the light energy loss and make the imaging picture clearer.

[0185] Therefore, the volume holographic recording grating prepared using the photopolymer type holographic recording medium has optical performance such as fast recording speed, low energy consumption efficiency and clear imaging.

[0186] The application also provides a holographic optical element, and the raw material of the holographic optical element includes the photopolymer type holographic recording medium described above. The holographic optical element includes but is not limited to a volume holographic grating and a holographic lens.

[0187] It can be understood that the holographic optical element provided in the present application has the advantages of the photopolymer type holographic recording medium provided in the present application, and has the optical properties of fast recording speed, low energy consumption efficiency, and clear picture, because the holographic optical element provided in the present application comprises the photopolymer type holographic recording medium provided in the present application.

[0188] The present application also provides an optical device comprising the holographic optical element as described above. The optical device includes but is not limited to a head-up display device (HUD), an augmented reality device (AR device), a virtual reality device (VR device), a photopolymer type holographic storage optical disc, etc. The photopolymer type holographic storage optical disc can realize erasable and rewritable and real-time recording, and is suitable for storing a large amount of data and has very fast data transmission speed.

[0189] As can be seen from the above, the optical device provided in the present application has the advantages of the holographic optical element provided in the present application, and has excellent optical performance, clear picture, and can store a large amount of data, because the optical device comprises the holographic optical element provided in the present application.

[0190] The thianthrene monomer, the preparation method of the thianthrene monomer, and the photopolymer type holographic recording medium containing the thianthrene monomer provided in the present application will be described below in combination with specific embodiments.

[0191] Example 1

[0192] Synthesis of thianthrene monomer G1

[0193]

[0194] Under nitrogen protection, thianthrene (10 mmol) was dissolved in anhydrous tetrahydrofuran solvent, and a solution of n-butyllithium (15 mmol) was added dropwise to the reaction system at -30 to -80°C. After the addition was completed, the reaction system was slowly warmed to room temperature and stirred for 0.5 to 3 hours. Then N,N-dimethylformamide (15 mmol) was added dropwise at -30 to -80°C and the reaction was stirred for 1 to 5 hours. After the reaction was completed, sufficient H2O was added to the reaction system to quench the reaction, and the organic phase was extracted with dichloromethane. The obtained organic phase was washed with water three times and dried with anhydrous sodium sulfate. The excess solvent was removed by rotary evaporation, and the compound P1 was separated by column chromatography.

[0195]

[0196] Under nitrogen protection, thianthrene (10 mmol) was dissolved in anhydrous tetrahydrofuran solvent, and n-butyllithium solution (15 mmol) was added dropwise to the reaction system at -30 to -80 °C. After the addition was completed, the reaction system was slowly warmed to room temperature and stirred for 0.5 to 3 h. Then compound P1 (15 mmol) was added dropwise at -30 to -80 °C and stirred for 1 to 5 h. After the reaction was completed, sufficient H2O was added to the reaction system to quench the reaction, and the organic phase was extracted with dichloromethane. The obtained organic phase was washed with water three times and dried with anhydrous sodium sulfate. The excess solvent was removed by rotary evaporation, and the compound P2 was separated by column chromatography.

[0197]

[0198] At 0 °C, compound P2 (10 mmol) and triethylamine (30 mmol) were dissolved in ethyl acetate, and after stirring for 10 min, acryloyl chloride (30 mmol) was added dropwise to the reaction system for reaction. After the reaction was completed, dilute hydrochloric acid was added to remove excess acryloyl chloride. The organic phase was washed with saturated NaCl solution, saturated NaHCO3 solution and deionized water in turn, and then dried with anhydrous sodium sulfate. The excess solvent was removed by rotary evaporation, and the thianthrene monomer G1 of the application was separated by column chromatography. The yield of G1 was 95.8%.

[0199] The characterization data are as follows:

[0200] 1 H NMR (600 MHz, CDCl3) δ 7.39 (t, J = 7.5 Hz, 2H), 7.34-7.29 (m, 3H), 7.32-7.21 (m, 10H), 7.02 (s, 1H), 6.16-6.07 (m, 1H), 5.90 (dd, J = 13.4, 0.9 Hz, 2H).

[0201] 13 C NMR (151 MHz, CDCl3) δ 166.23, 137.41, 135.67, 135.00, 134.38, 133.33, 131.66, 129.00, 127.70, 127.59, 127.41, 127.32, 126.98, 126.78, 126.55, 126.25, 74.99.

[0202] Example 2

[0203] Synthesis of thianthrene monomer G2

[0204]

[0205] Compound P2 (10 mmol) was dissolved in acetonitrile under ice bath, and sodium hydride (13 mmol) was slowly added in batches and stirred for 0.5-10 h, then 3-bromopropene (12 mmol) was added dropwise into the reaction system, and the reaction was continued to stir for 0.5-10 h after the dropwise addition was completed, after the reaction was completed, the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain thianthrene monomer G2, and the yield of G2 was 97%.

[0206] The characterization data are as follows:

[0207] 1 H NMR (600 MHz, CDCl3) δ 7.38 (dd, J = 8.0, 6.9 Hz, 2H), 7.34-7.29 (m, 2H), 7.31-7.26 (m, 6H), 7.29-7.21 (m, 4H), 5.85 (s, 1H), 5.88-5.77 (m, 1H), 5.24 (dt, J = 13.4, 1.0 Hz, 2H), 4.24 (dt, J = 6.2, 1.1 Hz, 2H).

[0208] 13 C NMR (151 MHz, CDCl3) δ 138.63, 135.14, 135.00, 134.38, 133.99, 133.56, 127.59, 127.41, 127.30, 126.77, 126.63, 126.49, 117.55, 78.53, 70.07.

[0209] Example 3

[0210] Synthesis of thianthrene monomer G3

[0211]

[0212] Compound P2 (10 mmol) was dissolved in acetonitrile under ice bath, and sodium hydride (13 mmol) was slowly added in batches and stirred for 0.5-10 h, then 3-bromopropene (12 mmol) was added dropwise into the reaction system, and the reaction was continued to stir for 0.5-10 h after the dropwise addition was completed, after the reaction was completed, the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain thianthrene monomer G2, and the yield of G2 was 97%.

[0213] The characterization data are as follows:

[0214] 1H NMR (600 MHz, CDC13) δ 7.45 (dd, J = 7.5, 1.8 Hz, 2H), 7.38 (t, J = 7.4 Hz, 2H), 7.34 - 7.21 (m, 10H), 5.94 (s, 1H), 4.34 (d, J = 2.9 Hz, 2H), 2.33 (t, J = 3.0 Hz, 1H).

[0215] 13 C NMR (151 MHz, CDC13) δ 138.71, 135.14, 135.00, 134.39, 134.00, 127.65, 127.42, 127.41, 127.29, 126.77, 126.63, 126.49, 79.43, 78.02, 75.10, 57.44.

[0216] Example 4

[0217] Synthesis of thianthrene monomer G4

[0218]

[0219] Compound P2 (10 mmol) was dissolved in tetrahydrofuran under ice bath, and sodium tert-butoxide (11 mmol) was slowly added in batches and stirred for 0.5-10 h, then 2-bromoethanol (12 mmol) was added dropwise into the reaction system, and the reaction was continued to stir for 0.5-10 h after the dropwise addition was completed. After the reaction was completed, dilute hydrochloric acid was slowly added dropwise to quench the reaction, and the excess solvent was removed by rotary evaporation. Compound P3-1 was separated by column chromatography.

[0220]

[0221] Compound P3-1 (10 mmol) and pyridine (30 mmol) were dissolved in ethyl acetate under ice bath, and after stirring for 10 min, methacryloyl chloride (30 mmol) was added dropwise into the mixed solution of compound P3 and pyridine at 0°C. After the reaction was completed, dilute hydrochloric acid was added to remove excess methacryloyl chloride. The organic phase was successively washed with saturated NaCl solution, saturated NaHCO3 solution and deionized water, and then dried over anhydrous sodium sulfate. The excess solvent was removed by rotary evaporation, and thianthrene monomer G4 was separated by column chromatography. The yield of G4 was 98%.

[0222] The characterization data are as follows:

[0223] 1H NMR (600 MHz, CDC13) δ 7.51 - 7.45 (m, 2H), 7.39 (t, J = 7.4 Hz, 2H), 7.34 - 7.21 (m, 11H), 5.95 (dq, J = 2.0, 1.0 Hz, 1H), 5.89 (d, J = 0.9 Hz, 1H), 5.61 (dq, J = 2.0, 1.0 Hz, 1H), 4.30 (t, J = 7.1 Hz, 2H), 3.94 (t, J = 7.1 Hz, 2H), 1.94 (t, J = 1.0 Hz, 3H).

[0224] 13 C NMR (151 MHz, CDC13) δ 167.09, 139.02, 135.86, 135.05, 134.39, 134.00, 128.02, 127.87, 127.68, 127.20, 127.02, 126.75, 126.68, 126.48, 125.91, 78.88, 66.63, 65.36, 18.23.

[0225] Example 5

[0226] Synthesis of thianthrene monomer G5

[0227]

[0228] Compound P2 (10 mmol) was dissolved in tetrahydrofuran under ice bath, and sodium tert-butoxide (11 mmol) was slowly added in batches and stirred for 0.5-10 h, then 5-bromo-1-pentanol (15 mmol) was added dropwise into the reaction system, after the addition was completed, the reaction was continued to stir for 0.5-10 h, after the reaction was completed, dilute hydrochloric acid was slowly added to quench the reaction, and the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain compound P3-2.

[0229]

[0230] Compound P3-2 (10 mmol) was dissolved in tetrahydrofuran under ice bath, and sodium hydride (12 mmol) was slowly added in batches and stirred for 0.5-10 h, then 3-bromopropene (15 mmol) was added dropwise into the reaction system, after the addition was completed, the reaction was continued to stir for 0.5-10 h, after the reaction was completed, the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain thianthrene monomer G5, and the yield of G5 was 97%.

[0231] The characterization data are as follows:

[0232] 1H NMR (600 MHz, CDC13) δ 7.41 - 7.35 (m, 2H), 7.34 - 7.27 (m, 4H), 7.30 - 7.21 (m, 9H), 5.92 - 5.80 (m, 2H), 5.24 (ddt, J = 13.4, 2.2, 1.0 Hz, 1H), 5.16 (ddt, J = 13.4, 2.2, 1.0 Hz, 1H), 3.97 (dt, J = 6.1, 0.9 Hz, 2H), 3.56 (t, J = 7.0 Hz, 2H), 3.38 (t, J = 6.9 Hz, 2H), 1.71 - 1.63 (m, 2H), 1.66 - 1.57 (m, 2H), 1.60 - 1.55 (m, 1H), 1.57 - 1.50 (m, 2H).

[0233] 13 C NMR (151 MHz, CDC13) δ 137.85, 135.05, 134.39, 133.99, 128.02, 127.87, 127.63, 127.20, 127.02, 126.78, 126.67, 126.48, 117.27, 79.16, 71.72, 70.29, 69.33, 29.80, 23.61.

[0234] Example 6

[0235] Synthesis of thianthrene monomer G6

[0236]

[0237] Compound P2 (10 mmol) was dissolved in tetrahydrofuran under ice bath, and sodium hydride (11 mmol) was slowly added in batches and stirred for 0.5-10 h, then 10-bromo-1-decanol (15 mmol) was added dropwise into the reaction system, after the addition was completed, the reaction was continued to stir for 0.5-10 h, after the reaction was completed, dilute hydrochloric acid was slowly added to quench the reaction, and the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain compound P3-3.

[0238]

[0239] Compound P3-3 (10 mmol) was dissolved in tetrahydrofuran under ice bath, and sodium hydride (12 mmol) was slowly added in batches and stirred for 0.5-10 h, then 3-bromopropynyl (15 mmol) was added dropwise into the reaction system, after the addition was completed, the reaction was continued to stir for 0.5-10 h, after the reaction was completed, the excess solvent was removed by rotary evaporation, and column chromatography was used to separate to obtain thianthrene monomer G6, and the yield of G6 was 97.3%.

[0240] The characterization data are as follows:

[0241] 1 H NMR (600 MHz, CDC13) δ 7.38 (t, J = 7.4 Hz, 1H), 7.34 - 7.26 (m, 2H), 7.29 - 7.21 (m, 4H), 4.15 (d, J = 2.9 Hz, 1H), 3.59 - 3.52 (m, 1H), 3.48 (t, J = 7.1 Hz, 1H), 2.45 (t, J = 2.9 Hz, 0H), 1.61 (dp, J = 12.9, 7.0 Hz, 2H), 1.40 - 1.27 (m, 2H), 1.30 - 1.21 (m, 4H).

[0242] 13 C NMR (151 MHz, CDC13) δ 137.25, 135.34, 134.06, 133.88, 129.66, 129.58, 127.22, 126.98, 126.88, 126.58, 126.50, 126.40, 77.99, 75.04, 70.74, 69.82, 57.74, 30.39, 30.02, 29.87, 29.63, 29.59, 29.54, 26.61, 26.52.

[0243] Example 7

[0244] Photopolymer type holographic recording mediums 7-1 to 7-6 were prepared using the thianthrene monomers in Examples 1 to 6 by mixing all components uniformly, filtering using a filter, and then coating the obtained filtrate onto a substrate and drying in a dark room with humidity of 10% to 85% and temperature of 20°C to 50°C to obtain the photopolymer type holographic recording medium. The specific components of the photopolymer type holographic recording mediums 7-1 to 7-6 are shown in Tables 1 to 6.

[0245] Table 1 Photopolymer type holographic recording medium 7-1

[0246]

[0247] Table 2 Photopolymer type holographic recording medium 7-2

[0248]

[0249]

[0250] Table 3 Photopolymer type holographic recording medium 7-3

[0251]

[0252] Table 4 Photopolymer type holographic recording medium 7-4

[0253]

[0254]

[0255] Table 5 Photopolymer type holographic recording medium 7-5

[0256]

[0257] Table 6 Photopolymer type holographic recording medium 7-6

[0258]

[0259]

[0260] Comparative Example

[0261] The components of the photopolymer type holographic recording medium 7-1 in Example 7 were substantially the same, except that the thianthrene monomer G1 was not added in the comparative example, and the content of 4-bromostyrene was increased to 37 wt%, thereby obtaining a common photopolymer type holographic recording medium.

[0262] Test Example

[0263] (1) The refractive index of the thianthrene monomers synthesized in Test Examples 1 to 6 was tested, and the results are shown in Table 7.

[0264] (2) The performance of the photopolymer type holographic recording medium 7-1 to 7-6 containing the thianthrene monomer of Example 7 and the common photopolymer holographic recording medium of the comparative example was tested, and the results are shown in Table 8.

[0265] In the test, each holographic recording medium in Example 7 was exposed to laser light of different wavelengths according to the different photosensitive systems, and the exposure intensity was 3 mW / cm 2 .

[0266] The detection light source was a 785 nm wavelength solid-state laser that did not react with the recording medium. The detection light was incident on the exposed area from the Bragg angle, and the transmitted light and the diffracted light were monitored in real time by a photodetector, and the single grating diffraction efficiency (η) of the photopolymer type holographic recording medium and the photosensitive sensitivity (S) of the photopolymer type holographic recording medium were calculated by Formulas (1) to (3).

[0267]

[0268] In the formula, η is the diffraction efficiency, η max is the highest diffraction efficiency, I d is the diffracted light, I tS represents transmitted light, S represents photosensitivity, E represents exposure energy, and ΔE represents the exposure energy required to achieve the highest diffraction efficiency.

[0269] Table 7 Refractive indices of the monomers synthesized in Examples 1-6

[0270]

[0271]

[0272] Table 8. Holographic performance parameters of the holographic recording media of Example 7 and the comparative example.

[0273]

[0274] like Figure 1 , Figure 2 As shown in Table 8, the exposure of the ordinary photopolymer holographic recording medium in the comparative example is 90.41 mJ / cm. 2 The sensitivity was 7.19 cm / mJ, and the diffraction efficiency was 42.2%, while the exposure of the photopolymer holographic recording medium obtained in Example 7 was less than 20 mJ / cm. 2 The sensitivity is greater than 100 cm / mJ, and the diffraction efficiency is greater than 95%.

[0275] Experimental results demonstrate that the photopolymer-based holographic recording medium provided in this application represents a breakthrough improvement over ordinary media: the exposure dose is increased from 90.41 mJ / cm². 2 Reduced to 20 mJ / cm 2 The sensitivity was improved from 7.19 cm / mJ to over 100 cm / mJ, and the diffraction efficiency increased from 42.2% to over 95%. Furthermore, the thiaanthracene monomers in Examples 1-6 of this application have a refractive index greater than 1.7, which, after polymerization with the polymerizable monomers, effectively increases the refractive index of the writing monomer and further enhances the refractive index difference between the writing monomer and the film-forming resin. It is understood that increasing the refractive index difference between the writing monomer and the film-forming resin helps improve the grating's ability to control incident light, reduces light energy loss, and further improves the diffraction efficiency of the optical device. This means that the photopolymer-type holographic recording medium provided by this application has high recording speed, excellent imaging quality, and other holographic properties.

[0276] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A thianthrene monomer characterized in that, The structure of the thianthrene monomer is as shown in any one of the following general formulae: Wherein, R1 represents hydrogen or methyl, n is a positive integer, and represents the number of methylene groups, n = 1-10.

2. A process for the preparation of a thianthrene monomer according to claim 1, characterized in that, When the structure of the thianthrene monomer is G1, the method comprises the following steps: Step S101, dissolve thianthrene in a first solvent to obtain a first mixture, and perform a first treatment operation on the first mixture, add a hydride reagent to the first mixture after the first treatment operation is completed, obtain a second mixture after reaction, perform a first treatment operation on the second mixture, and add a compound M1 to the second mixture after the first treatment operation is completed, obtain a third mixture after reaction, separate the third mixture, and obtain a compound P1; Wherein, the first treatment operation at least includes a cooling operation and a stirring operation, and the compound M1 is selected from one of N,N-dimethylformamide or piperidine-1-carbaldehyde; The structural formula of the compound P1 is as follows: Step S102, add the compound P1 to the second mixture after the first treatment operation is completed, obtain a fourth mixture after reaction, and separate the fourth mixture to obtain a compound P2; Step S103, dissolve the compound P2 and an acid binding agent in a second solvent, and add a compound M2 for reaction to obtain a fifth mixture after reaction, and separate the fifth mixture to obtain the thianthrene monomer G1; Wherein, the compound M2 is acryloyl chloride or methacryloyl chloride, and the structure of the compound P2 is as shown in the following formula: When the structure of the thianthrene monomer is G2 or G3, the method comprises the following steps: Step S201, dissolve the compound P2 in a first solvent, add a hydride reagent and stir for a first time period to obtain a sixth mixture, add a compound M3 to the sixth mixture for reaction, obtain a seventh mixture after reaction, and separate the seventh mixture to obtain the thianthrene monomer G2 or G3; wherein the compound M3 is selected from a compound represented by any one of the following structural formulae: When the structure of the thianthrene monomer is any one of G4-G6, the method comprises the following steps: Step S301, add a compound M4 to the sixth mixture and stir for a certain time period to obtain a seventh mixture, and separate the seventh mixture to obtain a compound P3; Step S302, dissolve the compound P3 and an acid binding agent in a second solvent, and add a compound M2 for reaction to obtain an eighth mixture after reaction, and separate the eighth mixture to obtain the thianthrene monomer G4; Step S303, dissolve the compound P3 in a first solvent, add a hydride reagent for reaction to obtain a ninth mixture after reaction, add a compound M3 to the ninth mixture and stir for a certain time period to obtain a tenth mixture, and separate the tenth mixture to obtain the thianthrene monomer G5 or G6; The structural formula of the compound M4 is as follows: The structural formula of the compound P3 is as follows: n is a positive integer and represents the number of methylene groups, n = 1 to 10.

3. The production method according to claim 2, characterized by, The first solvent at least includes one of petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide; And / or, the second solvent at least includes one of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide; And / or, the acid-binding agent at least includes one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium acetate, sodium hydroxide, potassium hydroxide, calcium oxide and potassium tert-butoxide; And / or, the hydride agent at least includes one of n-butyllithium, tert-butyllithium, phenyllithium, sodium hydride, potassium hydride, sodium amide, potassium amide, sodium bis(trimethylsilyl)amide, lithium diisopropylamide, potassium hydroxide, sodium hydroxide, sodium methoxide, sodium tert-butoxide, potassium tert-butoxide, triethylamine, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, tetramethylsilane triflate, potassium phosphate, potassium carbonate, sodium carbonate and sodium bicarbonate.

4. The production method according to claim 2, characterized by, In step S101, the molar ratio of the thianthrene to the hydride agent is 1:(1-1.5), and the molar ratio of the thianthrene to the compound M1 is 1:(1-1.5); And / or, in step S102, the molar ratio of the thianthrene to the compound P1 is 1:(1-1.5); And / or, in step S103, the molar ratio of the compound P2, the compound M2 and the acid-binding agent is 1:(1-3):(1-4); And / or, in step S201, the molar ratio of the compound P2 to the hydride agent is 1:(1-1.5), and the molar ratio of the compound P2 to the compound M3 is 1:(1-2); And / or, in step S302, the molar ratio of the compound P3, the compound M2 and the acid-binding agent is 1:(1-3):(1-4); And / or, in step S303, the molar ratio of the compound P3 to the hydride agent is 1:(1-1.5), and the molar ratio of the compound P3 to the compound M3 is 1:(1-2).

5. The preparation method according to claim 2, characterized in that, In step S101, the hydride agent is n-butyllithium, and the cooling operation includes setting the reaction temperature to -30 to -80℃; And / or, in step S102, the cooling operation includes setting the reaction temperature to -30 to -80℃; And / or, in step S103, the reaction temperature of the compound P2, the compound M2 and the acid-binding agent is 0℃; And / or, in step S201, the reaction temperature of the compound P2, the hydride agent and the compound M3 is 0℃; And / or, the reaction temperature in step S301 is 0℃; And / or, in step S302, the reaction temperature of the compound P3, the compound M2 and the acid-binding agent is 0℃; And / or, in step S303, the reaction temperature of the compound P3, the hydride agent and the compound M3 is 0℃.

6. A photopolymer type holographic recording medium, characterized by, The raw material thereof comprises the following components a)-component h); Component a) compound having multiple isocyanate reactive functional groups; Component b) polyisocyanate-based compound; Component c) thianthrene monomer; Component d) polymerizable monomer; Component e) photoinitiating system; Component f) chain transfer agent; Component g) optional catalyst; Component h) optional additive; The thianthrene monomer is at least one of the thianthrene monomers G1-G6 according to claim 1.

7. The photopolymer type holographic recording medium according to claim 6, wherein The composition and content of the photopolymer type holographic recording medium are as follows: Component a) compound having multiple isocyanate reactive functional groups 10-50 wt%; Component b) polyisocyanate-based compound 10-50 wt%; Component c) thianthrene monomer 1-30 wt%; Component d) polymerizable monomer 10-40 wt%; Component e) photosensitive initiator system 0.1-3 wt%; Component f) chain transfer agent 0.1-3 wt%; Component g) catalyst 0.1-5 wt%; Component h) additive 0.1-10 wt%.

8. The photopolymer type holographic recording medium according to claim 6, wherein The content of the thianthrene monomer in the entire photopolymer type holographic recording medium is 0.1-30 wt%; And / or, the isocyanate reactive functional group is a hydroxyl group, and the molar ratio of the hydroxyl group in the component a) compound having multiple isocyanate reactive functional groups to the isocyanate functional group in the component b) polyisocyanate-based compound is 1:

1.

9. The photopolymer type holographic recording medium according to claim 6, wherein, The isocyanate reactive functional group is a hydroxyl group; the compound having multiple isocyanate reactive functional groups includes a compound having a refractive index less than or equal to a first refractive index threshold and two or more hydroxyl functional groups, and the first refractive index threshold is any value between 1.5 and 1.55; And / or, the polyisocyanate-based compound includes a compound having a refractive index less than or equal to a second refractive index threshold and two or more isocyanate groups; the second refractive index threshold is any value between 1.5 and 1.55; And / or, the polymerizable monomer is at least one of an alkenyl naphthalene compound, an alkenyl anthracene compound, an alkenyl benzene compound, an acrylic acid compound, a methacrylic acid compound, an acrylate compound, a methacrylate compound, an N-vinyl pyrrole, an N-vinyl carbazole, an N-vinyl imidazole, an N-vinyl indole, an N-vinyl pyrrolidone, and a trans N-3-alkynyl butenyl carbazole; And / or, the photosensitive initiator system includes a photosensitizer and a photoinitiator; And / or, the chain transfer agent is a thiol compound; And / or, the catalyst is a tertiary amine catalyst and an organic metal catalyst; And / or, the additive includes at least one of a defoaming agent, a leveling agent, a plasticizer, and a water removal agent.

10. The photopolymer type holographic recording medium according to claim 9, wherein, The compound having multiple isocyanate reactive functional groups includes at least one of tetraethylene glycol, trimethylol ethane, glycerol, triethanolamine, a polyester polyol with a molecular weight of 200-2000, a polycarbonate polyol, and a polyether polyol; And / or, the polyisocyanate-based compound includes at least one of hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl) tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexyl methane diisocyanate. and / or, the chain transfer agent includes at least one of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol; and / or, the catalyst includes at least one of triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropylenediamine, N,N-bis(dimethylaminopropyl) isopropanolamine, dibutyl tin dilaurate, stannous octoate, potassium carboxylate catalyst, and bismuth carboxylate catalyst.

11. The photopolymer type holographic recording medium according to claim 9, wherein, The photosensitizer includes at least one of cyanine dye, fluorescein dye, coumarin ketone dye, nitrogen-containing aromatic heterocyclic compound, aromatic amine compound, benzylidene cycloalkanone compound; The photoinitiator includes at least one of aromatic ketone compound, benzoin and its derivatives, benzil ketals, acyl phosphine oxide, aryl borate ammonium, chromium salt, aryl diazonium salt, onium salt, organometallic compound, or these compounds; The mass ratio of the photosensitizer and the photoinitiator is (0.001-1):(0.1-3).

12. The photopolymer type holographic recording medium according to claim 9, wherein, The defoaming agent is an organosilicon defoaming agent and / or a polymer defoaming agent without organosilicon, and the content of the defoaming agent in the photopolymerizable holographic recording medium is less than or equal to 3wt%; and / or, the leveling agent is an organosilicon surface additive, and the content of the leveling agent in the photopolymerizable holographic recording medium is less than or equal to 3wt%; and / or, the plasticizer is at least one of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate, and the content of the plasticizer in the photopolymerizable holographic recording medium is less than or equal to 3wt%; and / or, the water removal agent includes at least one of p-toluenesulfonylisocyanate and triethyl orthoformate, and the content of the water removal agent in the photopolymerizable holographic recording medium is less than or equal to 3wt%.

13. A method for preparing the photopolymerizable holographic recording medium according to any one of claims 6-12, characterized in that, The compound having a plurality of isocyanate-reactive functional groups, the polyisocyanate-based compound, the thianthrene monomer, the polymerizable monomer, the photosensitive initiation system, the chain transfer agent, the catalyst, and the additive are weighed in a container, and are fully stirred to dissolve to form a mixture solution; The mixture solution is filtered using a filter membrane to obtain a first solution; The first solution is coated on a substrate, and after drying, the photopolymerizable holographic recording medium is obtained.

14. The method of claim 13, wherein, Drying is performed in a dark room with humidity of 10%-85% and temperature of 20°C-50°C.

15. A volume holographic recording grating, characterized by The photopolymerizable holographic recording medium used by the volume holographic recording grating includes the photopolymerizable holographic recording medium according to any one of claims 6-12.

16. A holographic optical element, characterized by The raw material includes the photopolymerizable holographic recording medium according to any one of claims 6-12.

17. An optical device, characterized by The holographic optical element includes the holographic optical element according to claim 16.

Images