JPH06324614A - Hologram recording material and hologram recording element - Google Patents

Abstract

PURPOSE:To provide the hologram recording material and hologram recording element with which the space modulation of improved sensitivity and the real time hologram recording are possible by the material consisting of a mixture of a high-polymer compd. which is a high-polymer compsn. of a structure having a photoconductivity and without having an inversion symmeterical center and has a carbazoryl group not substd. with an electron acceptive substituent on the side chain and a high-polymer compd. having an intramolecular charge transfer type dye structure or the element formed by using the material as a recording layer. CONSTITUTION:The films consisting of a soln. prepd. by mixing an N-carbazoryl buthyl acrylate polymer, styrene p-(4-dicyanovinyl phenoxy-styrene copolymer and trinitrofluororenone are formed on two glass substrates with ITO and thereafter, these substrates are pressed to constitute a cell. Both surface sides of the recording layer 1 are provided with transparent electrode layers 2, 2', by which the hologram recording surface is subjected to poling from a direction 6 perpendicular thereto and the hologram is recorded by irradiating the hologram recording surface with light rays 7, 7' from both sides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photorefractive hologram recording material and a hologram recording element capable of performing spatial light modulation, real-time hologram recording, and optical amplification.

[0002]

2. Description of the Related Art Conventionally, as a material which produces a photorefractive effect which is expected to be used as a spatial light modulation, a real-time hologram recording, a phase conjugate element,
2 such as lithium niobate, barium titanate, strontium barium niobate, bismuth silicon oxide
There are inorganic crystals that give rise to non-linear optical phenomena, and research and development have been conducted exclusively on these.

On the other hand, organic materials which generate a second-order nonlinear optical phenomenon have been attracting attention in recent years, and since such organic materials are expected to have large nonlinear optical constants, laser light wavelength conversion elements and Pockels caused by the nonlinear optical effect are particularly important. As an electro-optic modulator based on the effect, it is actively researched for use. In particular, among organic crystals that have been known as second-order nonlinear optical materials, 2-cyclooctylamino-5-nitropyridine is added to tetracyanoquinoline (TCN).
It has been confirmed that the organic crystal doped with Q) is newly noticed, and that the photorefractive effect, which has been confirmed only in the inorganic crystal until now, is also expressed in the organic crystal (Solid State Communications, Vol. 74, 8th
No., 867-870).

Further, an epoxy resin prepared by using a nitroaniline derivative as a raw material and having a photoconductive substance, diethylaminobenzaldehyde diphenylhydrazone, dispersed therein is used to promote the orientation of the nitroaniline portion by applying an electric field, and at the same time, a long light amount of 13 W / cm 2 is applied. By performing time holographic exposure, diffracted light of 0.001% order is observed (Physical Review Letter, No. 66).
Volume 14, Issue 1846-1849, 1991.
Year).

Further, a polarized product of a copolymer of cyanovinylaniline-containing methacrylate and carbazolylethyl methacrylate was subjected to holographic exposure for a long time, and a diffracted light of 0.001% order was observed ( Proceedings of the 41st Symposium on Macromolecules, Vol. 41, No. 7
No., 2487, 1992).

Further, as an element utilizing the optical refraction property, an optical amplifying element as disclosed in US Pat. No. 4,999,809 has been proposed. Further, it has been proposed that a partially tricyanovinylated carbazolyl pentyl methacrylate polymer may become a photorefractive polymer (Applied Physics Letter Vol. 60, No. 15, No. 1).
803-1805, 1992).

[0007]

However, in the case of an inorganic material such as bismuth silicon oxide, it is difficult to obtain a large single crystal, so that it is difficult to produce a large area hologram recording element, and the production yield is high. However, there is a problem that the hologram recording element becomes expensive due to its low height.

On the other hand, in the case of an organic material, it is considered that there is a possibility that the hologram recording element may have a large area and a low price.
-Cyclooctylamino-5-nitropyridine has a problem that both hologram recording sensitivity and light diffraction efficiency are low. Furthermore, since this organic material does not function as a hologram recording element unless it is a single crystal, there is a problem that it is difficult to obtain a hologram recording element having a large area as in the case of an inorganic material.

Further, even in a polymer composition, in a polymer in which a photoconductive material having a low molecular weight as described above is dispersed, the photoconductive material agglomerates due to heating in the poling treatment or the passage of time, which results in light Since the conductivity is lost and scattering occurs, there is a problem that it cannot be used as a practical hologram recording material.

Further, even in the case of a copolymer type polymer material, if various elements are copolymerized, the photoconductivity is lowered as compared with a usual photoconductive polymer material, and the hologram recording performance is not improved. was there.

Further, since the change in the refractive index due to the photorefractive property is small, a large diffraction efficiency cannot be obtained unless the thickness of the recording layer is large, but a partially tricyanovinylated carbazolyl pentyl methacrylate polymer is used. , The tricyanovinylcarbazolyl group also serves as a photoconductive spectral sensitizer for long wavelengths and an element exhibiting secondary hyperpolarization. Therefore, in order to obtain a large Pockels effect, tricyanovinylcarbazolyl group is used. If a large amount of groups is contained, the optical density becomes too large, and even if the recording layer thickness is large, there is a problem in that diffracted light is hardly generated due to absorption.

In order to solve the above-mentioned problems, the present invention provides a hologram recording material having a high recording sensitivity, which is an organic material and a non-crystalline polymer composition, and a hologram recording element using the hologram recording material. The purpose is to provide.

[0013]

In order to solve the above-mentioned problems, the hologram recording material of the present invention comprises a photoconductive element and an element exhibiting secondary hyperpolarization, and has an inversion symmetry center. A hologram recording material, which is a polymer composition having a structure not having the polymer compound, wherein the polymer compound contains a polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent as a polymer unit. And a polymer compound containing a polymerizable monomer having a structure of an intramolecular charge transfer type dye as a polymerized unit.

In the above structure, the structure of the intramolecular charge transfer dye is preferably a carbazolyl group substituted with an electron-accepting substituent. Further, in the above configuration,
It is preferable to contain an electron accepting substance capable of forming a charge transfer type complex when coexisting with a compound containing a carbazolyl group.

Next, the hologram recording element of the present invention is a hologram recording in which transparent electrode layers are provided on both sides of a recording layer made of a polymer composition having a photoconductive property and having no center of inversion symmetry. A hologram recording material, which is a polymer composition having a structure in which the recording layer includes an element having photoconductivity and an element exhibiting secondary hyperpolarization and has no center of inversion symmetry, Polymerizing a polymer compound containing a polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent as a polymer unit and a polymerizable monomer having an intramolecular charge transfer dye structure It is characterized by being a mixture containing a polymer compound contained as a unit.

[0016]

According to the above construction, the hologram recording material and the polymer composition forming the recording layer of the hologram recording element are a mixture of a polymer having photoconductivity and a polymer exhibiting secondary hyperpolarization. What is molded into a plate,
In the process of heating to above the glass transition temperature and cooling,
By applying an electric field and performing a poling treatment (polarization treatment), the polymer composition has a structure having no center of inversion symmetry, and the Pockels effect is exhibited. In particular, a monomer or polymer having a large dipole moment in the ground state and a large second-order hyperpolarizability β produces a larger Pockels effect, so that the hologram recording sensitivity and the light diffraction efficiency can be improved.

In the present invention, since a polymer having a carbazolyl group which is not substituted with an electron-accepting substituent is used as a photoconductive polymer, it is difficult to form a trap having a low energy in the polymer chain. The decrease in photoconductivity, especially the carrier mobility is small, and the hologram recording sensitivity can be improved.

Further, since the polymer having the structure of the intramolecular charge transfer type dye is used as the element exhibiting the secondary hyperpolarization, there is almost no deterioration in the performance due to the orientation relaxation of the dipole.
Furthermore, when the structure of the intramolecular charge transfer dye is a carbazolyl group substituted with an electron-accepting substituent, even if it becomes a cation radical, it is energetically close to the cation radical of the unsubstituted carbazolyl group, It does not become a deep trap.

Furthermore, in the case of containing an electron-accepting substance capable of forming a charge transfer complex when coexisting with a compound containing a carbazolyl group, the absorption wavelength of the carbazolyl group substituted with the electron-accepting substituent is Since the photoconductive sensitivity wavelength range can be set on the longer wavelength side, the carbazolyl group substituted with the electron-accepting substituent can be contained at a high concentration.

By providing transparent electrode layers on both sides of the recording layer made of such a polymer composition, an electric field can be applied in the thickness direction of the recording layer, and therefore, a direction perpendicular to the recording surface can be obtained. Therefore, it becomes possible to record an optical phase grating parallel to the recording surface, that is, a reflection hologram.

[0021]

EXAMPLES Examples of the hologram recording material and hologram recording element of the present invention will be described below.

FIG. 1 is a perspective view of an embodiment of the hologram recording element of the present invention, and FIG. 2 is a sectional view taken along the line AA '. In this recording element, transparent electrode layers 2 and 2'are provided on both sides of a recording layer 1 made of a polymer composition having photoconductivity and having no center of inversion symmetry.

The hologram material of the present invention, which is also a polymer composition having a photoconductive property which constitutes the recording layer of the hologram recording element of the present invention and has no inversion symmetry center,
Polymer Compound Containing Polymerizable Monomer Having Carbazolyl Group Not Substituted by Electron-Accepting Substituent as Polymerized Unit and Polymer Containing Polymerizable Monomer Having Intramolecular Charge Transfer Dye Structure as Polymerized Unit It can be obtained by subjecting a mixture containing a compound to a poling treatment in which an electric field is applied in a state of being heated to a glass transition temperature or higher. In particular, in order to generate a larger Pockels effect, the dipole moment in the ground state is large and 2
It is preferable to use a polymer compound containing as a polymerized unit a polymerizable monomer having the structure of an intramolecular charge transfer type dye having a large hyperpolarizability β as follows.

The carbazolyl group not substituted with an electron-accepting substituent is a π-conjugated system substituent such as a nitro group, a phenylazo group substituted with a nitro group, or a phenylvinyl group,
A carbazolyl group that is not substituted with a π-conjugated substituent such as a vinyl group substituted with one or more cyano groups, or a phenylazo group or a phenylvinyl group substituted with a vinyl group substituted with one or more cyano groups. And the N position may be substituted with alkyl or alkylene, and the sites other than the N position may be substituted with an alkyl group, an alkoxyl group, an alkylamino group, a halogen atom or the like.

As the polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent, various polymerizable monomers represented by the following formula (Formula 1) can be mentioned. A polymerizable monomer for forming a condensation polymer represented by the formula (Formula 2) can also be mentioned.

[0026]

[Chemical 1]

However, A is a hydrogen atom or a methyl group, B is a bond such as carbonyloxyalkylene, carbonylaminoalkylene, phenyleneoxyalkylene, and R ¹ and R ² are a hydrogen atom, a halogen atom, an alkyl group, an alkoxyl group. And R ³ is an optionally substituted alkyl group, a hydrogen atom or the like.

[0028]

[Chemical 2]

Wherein R is an optionally substituted alkyl group or a hydrogen atom, R ¹ and R ² are amino groups,
Examples thereof include aminoalkyl group, hydroxyl group, hydroxyalkyl group, carboxylalkyl group and glycidyl group.

In order to obtain a polymer compound containing the above-mentioned polymerizable monomers as polymerized units, these polymerizable monomers are homopolymerized, or (meth) acrylic acid and its ester, styrene and its It may be copolymerized with a derivative, an addition-polymerizable monomer such as vinyl acetate, or with a condensation-polymerizable monomer such as various diamines, various diols, and various hydroxyl group-substituted carboxylic acids.

However, when the content of the monomer other than the polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent increases, the carrier mobility decreases, so that the electron-accepting substituent is used. The content mole fraction of the polymerizable monomer having an unsubstituted carbazolyl group is preferably 80% or more.

The structure of the intramolecular charge transfer dye means an electron-donating group or an electron-donating moiety and an electron-accepting group or an electron-accepting moiety in a π-conjugated system such as a double bond, a triple bond or an aromatic ring. And specifically, a π-conjugated skeleton represented by the following formula (Formula 3) or a combination thereof, with an amino group, an alkyl or arylamino group, an alkoxyl group, a phenoxy group, and a hydroxyl group. Base,
An electron-donating group such as a quinone moiety or an electron-donating moiety, a nitro group, a formyl group, a cyano group, a carbonyl group,
Examples thereof include those in which an electron-accepting group or an electron-accepting moiety such as a carboxyl group, a sulfone moiety, or a phosphone moiety is substituted.

[0033]

[Chemical 3]

However, n is a positive integer, and A and B are carbon or nitrogen atoms. Further, as the structure of the intramolecular charge transfer dye, a carbazolyl group substituted with an electron-accepting substituent is particularly preferable.

The structure of the intramolecular charge transfer type dye can serve as a trap in the carrier transport of the photoconductive polymer to some extent, but if this is a carbazolyl group substituted with an electron-accepting substituent, it may be temporary. This is because even if it becomes a trap, it is thermally re-excited and easily contributes again as a carrier.

The polymerizable monomer having the structure of the intramolecular charge transfer dye is a polymerizable functional group such as vinyl group or methacryloyl group, or a condensable functional group such as hydroxyl group, amino group or carboxyl group as an alkyl group. , An intramolecular charge transfer type dye having a substituent through an aryl group or the like,
Specifically, a structure represented by the following formula (Formula 4) can be given.

[0037]

[Chemical 4]

However, A is a hydrogen atom or a methyl group, B is a bond such as carbonyloxy, carbonyloxyalkylene, amide, carbonylaminoalkylene, phenyleneoxyalkylene, oxyalkylene, and R ¹ and R ² are amino groups. , Aminoalkyl groups, hydroxyl groups, hydroxyalkyl groups, carboxylalkyl groups, glycidyl groups and the like.

In order to obtain a polymer compound containing the above-mentioned polymerizable monomers as polymerized units, these polymerizable monomers are homopolymerized, or (meth) acrylic acid and its ester, styrene and its It may be copolymerized with a derivative, an addition-polymerizable monomer such as vinyl acetate, or with a condensation-polymerizable monomer such as various diamines, various diols, and various hydroxyl group-substituted carboxylic acids.

Further, a polymer compound containing as a polymerized unit a polymerizable monomer having an intramolecular charge transfer type dye,
Regarding the wavelength for recording and reproducing the hologram, one that absorbs less light is preferable.

In general, the absorption wavelength tends to shift to a longer wavelength as it has a larger second-order hyperpolarizability β, but alkoxybenzylidene malononitrile, α- (4-alkoxyphenyl) -β-cyanoacrylic acid derivative, etc. Is
5 despite the very small absorption in the visible range
Since it has a secondary hyperpolarizability β similar to that of nitroanilines having absorption up to about 00 nm, it is preferable to use polymers having them, for example, an argon laser having a wavelength of 488 nm can be used as a recording light source. Become.

The inclusion of an electron-accepting substance capable of forming a charge-transfer complex when coexisting with a compound containing a carbazolyl group makes the photoconductive sensitivity wavelength longer or the quantum yield. This is a preferable configuration for increasing the rate.

The light absorption wavelength region of the charge transfer type complex is usually wide and the molecular extinction coefficient is not large, and the structure of the intramolecular charge transfer type dye does not need to also serve as the photoconductive spectral sensitization. By adjusting the addition amount of the electron-accepting substance, the optical density at the recording wavelength of the hologram can be easily adjusted.

Specific examples of such an electron accepting substance include trinitrofluorenone, tetranitrofluorenone, trinitrofluoridene malononitrile, terephthalonitrile, tetracyanobenzene, tetracyanoethylene and the like. By adding these, photoconductive sensitivity is obtained not only for blue light but also for yellow light and red light. When these additive substances have a reactive functional group, they can be copolymerized as a comonomer.

There are roughly two methods for processing the above-mentioned polymer composition into a plate shape. The first method is a method of melting and molding, which can be processed into various thicknesses or shapes by using a kneading extruder, a hot press machine, an injection molding machine or the like.

The second method is a method of molding in a solution state, which can be formed into a thin film or a plate by a dip method, a cast method, a spin coating method or the like.
These methods generally tend to be difficult to form thick ones, but among them, the casting method of molding a high-concentration solution using a doctor knife and dropping the high-concentration solution through a slit from both sides The dry casting method is preferred.

Further, a method combining the above methods, that is, a method in which a relatively thin film is once formed from a solution state, and then the films are laminated and melted by a hot press machine or the like is possible.

The transparent electrode layers 2, 2'formed on both sides of the recording layer 1 made of a polymer composition having photoconductivity and producing the Pockels effect have wavelengths of light used for hologram recording or reproduction. The transparent electrode material such as ITO (Indium-Tin Oxide Alloy) or SnO ₂ can be used as long as it has good light transmittance. The thickness of the transparent electrode layers 2 and 2'is preferably excluded from the interference condition determined by the wavelength of light used for recording or reproduction or the incident angle of light.

FIG. 3 is a sectional view of another embodiment of the hologram recording element of the present invention. In this recording element, transparent electrode layers 2 and 2'are provided on both sides of a recording layer 1 made of a polymer composition having photoconductivity and having no center of inversion symmetry, and further insulation protection is provided on the surface. Forming layers 3, 3 '. By providing the insulating protective layers 3 and 3'on the surfaces of the transparent electrode layers 2 and 2'in this way, the transparent electrode layers can be protected.

FIG. 4 is a sectional view of another embodiment of the hologram recording element of the present invention. This recording element has a transparent substrate 5
A first transparent electrode layer 2'is provided on the first transparent electrode layer 2 '
A recording layer 1 made of a polymer composition having a photoconductive property and having no center of inversion symmetry is provided on the above, and a second transparent electrode layer 2 is provided on the recording layer 1. By thus forming the basic structure of the hologram recording element on the transparent substrate or the like, the mechanical strength is improved.

The transparent substrate 5 may be any one as long as it has a good light transmittance with respect to the wavelength of light used for hologram recording or reproduction, and a quartz plate or various glass substrates can be used as the transparent substrate material. The thickness of the transparent substrate 5 is preferably about 50 μm or more in order to prevent optical interference from occurring in the substrate. In order to effectively utilize the amount of light used for hologram recording or reproduction, it is also preferable to provide an antireflection coating for preventing surface reflection on the side of the transparent substrate 5 where the transparent electrode layer is not provided.

As a method for forming the transparent electrode layers 2, 2'on the recording layer 1 or the transparent substrate 5 made of the above polymer composition, a vacuum film forming method such as vacuum deposition or sputtering can be used. . The transparent substrate 5 such as quartz or glass
As a method of forming the transparent electrode layers 2 and 2 ′ on the above, a wet film forming method such as a spray pyrolysis method can be used.

Next, the poling treatment for imparting the property of producing the Pockels effect to the polymer composition constituting the recording layer 1 will be described. As described above, the polymer composition having the transparent electrode layers 2 and 2'formed on both sides thereof is subjected to a poling treatment in which an electric field is applied in a state of being heated to a glass transition temperature or higher, whereby a part of the monomer or polymer is obtained. As a result, the dipole is oriented and polarized. When cooled below the glass transition temperature in such a polarized state, the molecular orientation is fixed and the structure does not have an inversion symmetry center. A Pockels effect occurs in a substance having such a structure.

The electric field is applied by applying a voltage between the transparent electrode layers formed on both sides. If the application of the electric field is stopped in the heated state, the orientation of the molecules is relaxed and the Pockels effect becomes smaller.Therefore, the application of the electric field is continued at least until the glass transition temperature is cooled to near room temperature. It is preferable to carry out. Since the polymer composition subjected to the poling treatment has photoconductivity, it is preferable to carry out the poling treatment in an environment where light of a wavelength having photoconductive sensitivity is not exposed.

FIG. 5 is a sectional view of another embodiment of the hologram recording element of the present invention. In this recording element, insulating layers 4 and 4'are provided on both surface sides of a recording layer 1 made of a polymer composition having photoconductivity and producing the Pockels effect, and transparent electrode layers 2 and 2'are provided thereon. It is provided. By providing such insulating layers 4 and 4 ', the dielectric strength can be improved and the electric field applied in the recording layer can be increased. Note that the insulating layer may be provided on only one surface.

Next, a hologram recording method using the hologram recording element of the present invention will be described. The polymer composition constituting the recording layer of the hologram recording element of the present invention as described above is a so-called poled polymer (polarized polymer), and the polymer composition is perpendicular to the surface of the recording layer. Each of the dipoles has a structure in which they are oriented.

As shown in FIG. 6, by providing transparent electrode layers 2 and 2'on both sides of the recording layer 1, it is possible to poll in the direction 6 perpendicular to the hologram recording surface, and from both sides of the hologram recording surface. A hologram can be recorded by irradiating with light 7 and 7 '. In this case, since the interference fringes 8 recorded in the recording layer are nearly parallel to the hologram recording surface, the electro-optic constant γ ₃₃ can be effectively used, and a transparent electrode layer can be used to generate a large electric field in the recording layer. Can be applied. Reference numeral 9 is a power supply for applying an electric field, and 10 is a switch.

The recording layer made of the above polymer composition contains
Since an electric field is applied during exposure, radical ion pairs are efficiently generated in the bright portion of the interference fringes, and one or both of them move as carriers. Then, the irradiation light is blocked and the application of the electric field is stopped, and the hologram recording is completed.
The carrier distribution remains at the same pitch as the interference fringe pitch even if there is a phase shift with respect to the light interference fringes, and as a result, a charge distribution is formed in the polymer composition. Therefore, the internal electric field due to this residual charge is almost the same as the interference fringe pitch during exposure. Then, depending on the distribution of this internal electric field,
The Pockels effect occurs in the polymer composition in the recording layer,
Since a refractive index distribution that is almost the same as the interference fringe pitch during exposure occurs, it is possible to record a hologram by changing the refractive index.

As the light used for recording, coherent (coherent) light having a wavelength within the photoconductive sensitivity region of the polymer composition having photoconductivity is used. In particular, it is preferable to use laser light that can easily obtain coherent light.
When performing hologram recording, the coherent light from the same light source is split into two light beams by a beam splitter or the like, and the optical path length to the hologram recording element is set so that both light paths have substantially the same optical path length. Preferably.

FIG. 7 shows an example of an interferometer which can use the hologram recording method of the present invention, using an overall schematic view. The light flux emitted from the laser light source 21 is reflected by the mirror 2
The beam enters the shutter 23 via 2 and is then split into two light beams by the beam splitter 24. One light beam becomes divergent light by the lens 25 and illuminates the subject 20, and the other light beam diverges by the lens 27 via the mirror 26. It becomes light and irradiates the recording layer 1. The light emitted to the subject 20 is
It is modulated by the information of the subject, and a part thereof illuminates the recording layer 1. In the recording layer 1, the two lights interfere with each other to form a carrier distribution according to the interference fringes. The timer device 28 controls the exposure time and the electric field applied to the recording layer.

Next, a hologram reproducing method using the hologram recording element of the present invention will be described. As shown in FIG. 8, hologram reproduction is performed by irradiating one light beam used at the time of exposure as reproduction light 11.

Since the reproduction light 11 is incident in a direction nearly perpendicular to the surface of the formed interference fringe, the contribution of the electro-optical constant of the component of r ₁₃ or r ₂₃ is large, but since it is a poled polymer, it is r. ₁₃ because _{(= r 23) = r 33} /3 can be secured, it is possible to obtain a refractive index distribution with a sufficient refractive index change.

Since the hologram recording method of the present invention forms a reflection-type hologram having wavelength selectivity, it is not necessary to use coherent light such as laser light during reproduction, and a white light source such as sunlight or a light bulb can be used. Can be used. However, since the photoconductive sensitivity of the recording layer increases as the wavelength becomes shorter, it is preferable that the reproduction light has less short-wavelength component in order to prevent generation of new carriers. In order to suppress the image distortion of the hologram, when the recording light is divergent light, the reproducing light is also divergent light, and when the recording light is parallel light, the reproducing light is also convergent light. preferable. Furthermore, when a large electric field is applied when reproducing light is irradiated, carrier generation at the time of light irradiation is promoted and the recorded carrier distribution is erased. preferable.

Next, a hologram erasing method using the hologram recording element of the present invention will be briefly described. In order to erase the recorded hologram, the carrier having been recorded in the recording layer is generated by irradiating the recording layer with light of a wavelength component having photoconductive sensitivity of the recording layer in a strong light amount to generate a new carrier. The distribution disappears. It is also preferable to apply an electric field to the recording layer together with the irradiation of the erasing light. Further, in order to uniformly erase the recording layer, it is preferable to irradiate the hologram recording element with a uniform light amount. The erasing light does not have to be coherent light.

Next, specific examples of the hologram recording material and the hologram recording element of the present invention will be described in detail. (Example 1) (Synthesis of Raw Material for Holographic Recording Material) 10 parts by weight of N-carbazolyl butyl acrylate and 0.01 of azobisisobutyronitrile were placed in a three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a stirrer. Into 40 parts by weight of tetrahydrofuran was added 1 part by weight, and polymerization was carried out at 80 ° C. for 5 hours while introducing nitrogen while stirring.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After filtering off with suction filtration, it was dried under vacuum to obtain a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group not substituted with an electron-accepting substituent.

Then, 10 parts by weight of styrene and p- were added to a three-necked flask equipped with a nitrogen introduction tube, a reflux condenser and an agitator.
10 parts by weight of (4-dicyanovinylphenoxy) styrene and 0.02 part by weight of azobisisobutyronitrile were added, dissolved in 80 parts by weight of tetrahydrofuran, and polymerized at 80 ° C. for 5 hours while introducing nitrogen while stirring.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After being separated by suction filtration, vacuum drying was performed to obtain a polymer compound containing a polymerizable monomer having an intramolecular charge transfer type dye structure as a polymerized unit.

(Production of Holographic Recording Element) 6 parts by weight of a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group not substituted with the electron-accepting substituent obtained above, and an intramolecular charge transfer 0.02 part by weight of trinitrofluorenone was dissolved in 15 parts by weight of tetrahydrofuran in 4 parts by weight of a polymer compound containing a polymerizable monomer having a type dye structure as a polymerized unit.

On the other hand, two glass slides having an ITO layer formed thereon were prepared, and the above-mentioned solution was applied onto the glass slide using a doctor knife and dried to form a polymer composition thin film of about 60 μm. did.

A slide glass on which an ITO layer having a polymer composition thin film formed thereon was laminated with a 100 μm-thick PET spacer interposed therebetween so that the polymer composition thin films faced each other, and heated to 150 ° C. A cell having a polymer composition layer with a thickness of about 100 μm was obtained by press-melting and molding with a hot press machine.

Next, the polling process will be described.
This sample was heated to 95 ° C. on a hot plate in a dark room, and then 10 kV was applied between both electrodes. After the lapse of 10 minutes, the heater of the incubator was turned off, and the mixture was allowed to cool while an electric field was applied. Since the temperature dropped to room temperature after 1 hour, the applied electric field was removed and the sample was taken out. Through the above steps, the hologram recording element of the present invention could be obtained.

(Hologram Recording Method, Reproducing Method, and Erasing Method) An interferometer using an argon laser as a light source was assembled in a dark room, and the above-mentioned hologram recording element was incident on the surface with an incident angle of 30 degrees from one surface. The other surface was installed so that it could be incident at 5 degrees.

Next, irradiation of light quantity of about 100 mW / cm 2 was started from both sides while applying 1 kV between the transparent electrode layers. After 10 seconds, the applied electric field was removed and the light irradiation was stopped.

Subsequently, when only the reproduction light with an incident angle of 30 degrees was irradiated from one surface, reflected diffracted light with an emission angle of about -5 degrees was observed, and the hologram was reproduced. Next, in order to erase the hologram, three erase lights from the xenon lamp are used.
Irradiate for 0 seconds. An attempt was made to reproduce a hologram using the above-mentioned reproduction optical system, but no reflected diffracted light was observed.

(Example 2) (Synthesis of hologram recording material) In a three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a stirrer, 19.5 parts by weight of N-ethylcarbazolylaldehyde-4-vinylaniline and styrene were added. Add 0.5 parts by weight and 0.02 parts by weight of azobisisobutyronitrile, and add 60 parts of tetrahydrofuran.
It is dissolved in 1 part by weight, and nitrogen is introduced with stirring at 80 ° C. for 5
Polymerized for hours.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After filtering off with suction filtration, it was dried under vacuum to obtain a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group not substituted with an electron-accepting substituent.

Subsequently, 10 parts by weight of 70% saponified polyvinyl alcohol and 10 parts by weight of 4-nitrophenylmethylaminoacetaldehyde dimethyl acetal were placed in a three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a stirrer.
Dissolved in 80 parts by weight of ethanol mixed solvent, hydrochloric acid 20 m
1 was added, and the mixture was acetalized at 50 ° C. for 12 hours with stirring.

The solid substance gelled in the flask was dissolved in 100 parts by weight of dimethylformamide, and subsequently poured into 1000 parts of acetonitrile for reprecipitation. After being separated by suction filtration, vacuum drying was performed to obtain a polymer compound containing a polymerizable monomer having an intramolecular charge transfer type dye structure as a polymerized unit.

(Production of Holographic Recording Element) 6 parts by weight of a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent, and an intramolecular charge transfer type 4 parts by weight of a polymer compound containing as a polymerized unit a polymerizable monomer having a dye structure,
0.04 parts by weight of tetranitrofluorenone was dissolved in 15 parts by weight of tetrahydrofuran.

On the other hand, two glass slides on which an ITO layer was formed were prepared, and the above solution was applied onto it using a doctor knife and dried to form a polymer composition thin film of about 60 μm. did.

A slide glass on which an ITO layer having a polymer composition thin film formed thereon was laminated with a 100 μm-thick PET spacer interposed therebetween so that the polymer composition thin films faced each other and heated to 150 ° C. A cell having a polymer composition layer with a thickness of about 100 μm was obtained by press-melting and molding with a hot press machine.

Next, the polling process will be described.
This sample was heated to 95 ° C. on a hot plate in a dark room, and then 10 kV was applied between both electrodes. After the lapse of 10 minutes, the heater of the incubator was turned off, and the mixture was allowed to cool while an electric field was applied. Since the temperature dropped to room temperature after 1 hour, the applied electric field was removed and the sample was taken out. Through the above steps, the hologram recording element of the present invention could be obtained.

(Hologram Recording and Reproduction) Hologram recording and reproduction was possible in the same manner as in Example 1 except that a helium-neon laser was used as the laser light source.

(Example 3) (Synthesis of raw material for hologram recording material) In a three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a stirrer, 9 parts by weight of N-carbazolylethyl acrylate, 1 part by weight of hexyl acrylate and Azobisisobutyronitrile 0.01
Into 40 parts by weight of tetrahydrofuran was added 1 part by weight, and polymerization was carried out at 80 ° C. for 5 hours while introducing nitrogen while stirring.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After filtering off with suction filtration, it was dried under vacuum to obtain a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group not substituted with an electron-accepting substituent.

Subsequently, 10 parts by weight of styrene and 2 parts of styrene were placed in a three-necked flask equipped with a nitrogen introduction tube, a reflux condenser and an agitator.
[10 parts by weight of N- (3-dicyanovinylcarbazolyl) propyl acrylate and 0.02 parts by weight of azobisisobutyronitrile were added and dissolved in 80 parts by weight of tetrahydrofuran. Polymerization was carried out at ℃ for 5 hours.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After being separated by suction filtration, vacuum drying was performed to obtain a polymer compound containing a polymerizable monomer having an intramolecular charge transfer type dye structure as a polymerized unit.

(Production of Holographic Recording Element) 6 parts by weight of a polymer compound containing as a polymerized unit a polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent and an intramolecular charge transfer type 4 parts by weight of a polymer compound containing as a polymerized unit a polymerizable monomer having a dye structure,
0.02 parts by weight of trinitrofluorenylidene malononitrile was dissolved in 15 parts by weight of tetrahydrofuran.

On the other hand, two glass slides having an ITO layer formed thereon were prepared, and the above solution was applied onto the glass slide using a doctor knife and dried to form a polymer composition thin film of about 60 μm. did.

A slide glass having an ITO layer formed with a thin film of the polymer composition was laminated so that the thin film of the polymer composition faced each other with a spacer made of PET having a thickness of 100 μm interposed therebetween, and heated to 150 ° C. A cell having a polymer composition layer with a thickness of about 100 μm was obtained by press-melting and molding with a hot press machine.

Next, the polling process will be described.
This sample was heated to 86 ° C. on a hot plate in a dark room, and then 10 kV was applied between both electrodes. After 30 minutes, the heater of the incubator was turned off, and it was allowed to cool while an electric field was applied. Since the temperature dropped to room temperature after 1 hour, the applied electric field was removed and the sample was taken out. Through the above steps, the hologram recording element of the present invention could be obtained.

(Hologram Recording Method, Reproducing Method, and Erasing Method) An interferometer using an argon laser as a light source was assembled in a dark room, and the above-mentioned hologram recording element was incident on the surface at an incident angle of 30 degrees from one surface. The other surface was installed so that it could be incident at 5 degrees.

Further, two optical power meters were installed to monitor the transmitted light intensity of each incident light. Next, with 1 kV applied between the transparent electrode layers, 70 mW / cm ² from the incident angle 30 ° side and 30 mW from the other 5 ° incident side.
Irradiation with a light amount of / cm2 was started.

With the start of light irradiation, the transmitted light intensity on the incident side began to gradually increase 5 degrees, and after 120 seconds, the light amount reached about twice the initial amount. As described above, it has been clarified that optical amplification is possible by using the hologram recording element of the present invention.

Comparative Example 1 (Synthesis of Raw Material for Holographic Recording Material) In a three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a stirrer, 5 parts by weight of N-carbazolyl ethyl methacrylate and 2- [N-methyl] were used. Add 3 parts by weight of -N- (4-nitrophenyl) aminoethyl methacrylate, 2 parts by weight of ethyl acrylate and 0.01 parts by weight of azobisisobutyronitrile, dissolve in 40 parts by weight of tetrahydrofuran, and introduce nitrogen while stirring. While polymerizing at 80 ° C for 5 hours.

Next, after allowing to cool, it was poured into 1000 parts of methanol for reprecipitation. After filtering by suction filtration, the polymer was vacuum dried to obtain a polymer compound having a photoconductive functional group and an intramolecular charge transfer dye structure.

(Production of Holographic Recording Element) 10 parts by weight of the polymer compound obtained above and trinitrofluorenone 0.1.
02 parts by weight were dissolved in 15 parts by weight of tetrahydrofuran.

On the other hand, two glass slides having an ITO layer formed thereon were prepared, and the above solution was applied onto the glass slide using a doctor knife and dried to form a polymer composition thin film having a thickness of about 60 μm. did.

A slide glass on which an ITO layer having a polymer composition thin film formed thereon was laminated with a 100 μm-thick PET spacer interposed therebetween so that the polymer composition thin films faced each other and heated to 150 ° C. A cell having a polymer composition layer with a thickness of about 100 μm was obtained by press-melting and molding with a hot press machine.

Next, the polling process will be described.
This sample was heated to 90 ° C. on a hot plate in a dark room, and then 10 kV was applied between both electrodes. After the lapse of 10 minutes, the heater of the incubator was turned off, and the mixture was allowed to cool while an electric field was applied. Since the temperature dropped to room temperature after 1 hour, the applied electric field was removed and the sample was taken out. Through the above steps, the hologram recording element could be obtained.

(Hologram Recording Method, Reproducing Method, and Erasing Method) An interferometer using an argon laser as a light source was assembled in a dark room, and the hologram recording element described above had an incident angle of 30 degrees from one surface with respect to the surface. The other surface was installed so that it could be incident at 5 degrees.

Next, irradiation of light amount of about 100 mW / cm ² was started from both sides while applying 1 kV between the transparent electrode layers. After 10 seconds, the applied electric field was removed and the light irradiation was stopped.

Subsequently, only the reproducing light having an incident angle of 30 degrees was irradiated from one surface, but no diffracted light was observed.

[0105]

As described above, the hologram recording material and the hologram recording element of the present invention are capable of recording, reproducing and erasing a hologram any number of times, such as optical spatial modulation, real-time hologram recording and phase conjugate element. The present invention provides a hologram recording element suitable for an optical amplification element and the like.

In particular, since a polymer having a carbazolyl group which is not substituted with an electron-accepting substituent is used as a polymer having photoconductivity, it is difficult to form a trap having a low energy in the polymer chain, and the photoconductivity is low. Properties, especially the decrease in carrier mobility, is small, and the hologram recording sensitivity can be improved.

Further, since the polymer having the structure of the intramolecular charge transfer type dye is used as the element exhibiting the secondary hyperpolarization, there is almost no deterioration in the performance due to the relaxation of the orientation of the dipole.
Furthermore, when the structure of the intramolecular charge transfer dye is a carbazolyl group substituted with an electron-accepting substituent, even if it becomes a cation radical, it is energetically close to the cation radical of the unsubstituted carbazolyl group, It does not become a deep trap.

Further, when an electron-accepting substance capable of forming a charge transfer complex when coexisting with a compound containing a carbazolyl group is contained, the absorption wavelength of the carbazolyl group substituted with the electron-accepting substituent is contained. Since the photoconductive sensitivity wavelength range can be set on the longer wavelength side, the carbazolyl group substituted with the electron-accepting substituent can be contained at a high concentration.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a hologram recording element of the present invention.

FIG. 2 is a sectional view taken along the line AA ′ of the embodiment of the hologram recording element of the present invention shown in FIG.

FIG. 3 is a sectional view of another embodiment of the hologram recording element of the present invention.

FIG. 4 is a sectional view of another embodiment of the hologram recording element of the present invention.

FIG. 5 is a sectional view of another embodiment of the hologram recording element of the present invention.

FIG. 6 is a schematic view of an embodiment showing a hologram recording method of the present invention.

FIG. 7 is an overall schematic diagram of an example of an interferometer that can use the hologram recording method of the present invention.

FIG. 8 is a schematic view of an embodiment of a method for reproducing a hologram recorded in the hologram recording element of the present invention.

[Explanation of symbols]

 1 Recording layer 2, 2'Transparent electrode layer 3, 3'Insulation protection layer 4 Insulation layer 5 Transparent substrate 6 Arrow indicating the poling direction 7,7 'Irradiation light for recording 8 Interference fringes 9 Power supply 10 Switch 11 Reproduction light 12 Reflected diffracted light 20 Subject 21 Laser light source 22, 26 Mirror 23 Shutter 24 Beam splitter 25, 27 Lens 28 Timer device

Claims (4)

[Claims] 1. A hologram recording material, which is a polymer composition having a structure containing a photoconductive element and an element exhibiting secondary hyperpolarization and having no center of inversion symmetry, said polymer compound Is a polymer compound containing a polymerizable monomer having a carbazolyl group which is not substituted with an electron-accepting substituent as a polymerized unit, and a polymerizable monomer having an intramolecular charge transfer dye structure as a polymerized unit. A hologram recording material, which is a composition containing a polymer compound containing the same. 2. The structure of the intramolecular charge transfer dye is a carbazolyl group substituted with an electron-accepting substituent.
The hologram recording material described. 3. The hologram recording material according to claim 1, further comprising an electron-accepting substance capable of forming a charge-transfer complex when coexisting with a compound containing a carbazolyl group. 4. A hologram recording element having a transparent electrode layer on both sides of a recording layer made of a polymer composition having photoconductivity and having no center of inversion symmetry.
A hologram recording material, which is a polymer composition having a structure in which the recording layer includes an element having photoconductivity and an element exhibiting secondary hyperpolarization and has no center of inversion symmetry, wherein the polymer compound is A polymer compound containing a polymerizable monomer having a carbazolyl group not substituted with an electron-accepting substituent as a polymerized unit, and a polymerized monomer having an intramolecular charge transfer dye structure as a polymerized unit A hologram recording element comprising a composition containing a polymer compound.