JPH07306425A - Photo-refractive material composition and device using the same - Google Patents

Abstract

PURPOSE:To prepare a composition showing high stability, large photoconductivity, electro-optical characteristic, moldability and mechanical strength by consisting a material of an inorganic photo-refractive material dispersed in another material. CONSTITUTION:This composition consists of the inorganic photo-refractive material dispersed in another material. For example, the inorganic photo- refractive material is mixed with a non-conjugated high polymer. And the non- conjugated high polymer is selected from polystyrene, polybutylene terephthalate or the like. The inorganic photo-refractive material is mixed with a piezoelectric or ferroelectric organic high polymer. The piezoelectric or ferroelectric organic high polymer is selected from polyvinyldene chloride, cyano high polymer or the like. The inorganic photo-refractive material is mixed with a liquid crystal high polymer. Or the inorganic photo-refractive material is mixed with a high polymer or high polymer mixture having photoconductivity. As a result, the high performance photo-refractive composition is obtained and is suitably used for various kinds of optical application.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to inorganic photorefractive material compositions for electronic and optical applications.

[0002]

BACKGROUND OF THE INVENTION Photorefractive materials are non-linear optical materials that combine the three properties of electro-optical properties, photoconductivity, and photoionizable lattice defects. Empirically, two required properties associated with photorefractive materials are (1) lack of central symmetry that produces the Pockels linear EO effect, and (2) density of deep levels sufficient to produce space charges. This causes a current to be generated by the laser light and the presence of an electric field can change the refractive index. The electric field modulates the refractive index by the linear electro-optic effect. The movement of ionized charges occurs due to diffusion, movement of electric field excitation, or photovoltaic effect. The diffraction grating having a refractive index generated in the photorefractive crystal can be erased by using light in an appropriate wavelength range. These are, for example, P. Gunther Jay P. Hignard "Photorefractive.
Materials and There Applications (PG
unter, JP Huignard, Photorefractive Materials and
TheirApplications I & II ", Springer-Verlag (19
88, 1989)). Photorefractive effects have been observed in a wide variety of electro-optic crystals. Barium titanate as the best known
(BaTiO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), potassium niobate (K
NbO ₃ ), Sr _x Ba _1-x Nb ₂ O ₆ (SBN), Bi ₁₂ S
iO ₂₀ (BSO), Bi ₂ GeO ₂₀ (BSO), Bi ₁₂ Ge
O ₂₀ (BGO), Bi ₁₂ TaO ₂₀ (BTO), KTa _1-x N
b _x O ₃ (KTN), GaAs, InP and the like. These inorganic EO crystals have been considered suitable for holographic techniques. For these, for example,
Kei Shin Athi Fondo Gee Roche (A.Roy
, K. Singh, Atti. Fond. G. Rochi, 48, 327.
(1993)). The factors that select photorefractive materials for different applications are photorefractive sensitivity, operating range (maximum refractive index change), photorefractive recording and erasing time, spectral sensitivity, spatial frequency, external electric field dependence and resolution.

Photorefractive materials can be classified into three types. (1) BaTiO ₃ , LiNbO ₃ , LiT
Oxygen octahedral ferroelectrics such as aO ₃ , KNbO ₃ , SBN, and KTN. The storage time of the recorded hologram or the disappearance time of the diffraction grating is in the range of milliseconds for KNbO ₃ to several years for several hours of KTN and the fixing process of LiNbO ₃ . Generally, SBN is used in the blue-green wavelength range. They are used in hologram recording media, optical bistables, phase conjugation, resonators and optical computing.
(2) A silenite material having a tetrahedral oxide structure such as BSO, BGO and BTO. The bandwidth of BTO is narrower than that of BSO and BGO, and is noted from the viewpoint of application to infrared wavelengths. Although the gain of sillenite is small, the speed of photorefractive response is considerably faster than that of BaTiO ₃ or LiNbO ₃ . (3) GaAs, GaSb, InAs, InSb
III-V group such as CuCl, CdS, CdSe, CdT
II-VI group semiconductor crystals such as e, ZnS, ZnSe, ZnTe, HgSe, and HgS. There is an example in which a picosecond photorefractive response was obtained using a GaAs crystal. The fast response can be used for optical information processing, optical computing and optical switching. The photorefractive effect of semiconductor crystals occurs at wavelengths of 0.9-1.6μ.

[0004]

Inorganic crystal photorefractive materials have been developed, but none of them can be integrated because of poor moldability and processability. Furthermore, it is generally difficult to form a homogeneous single crystal or thin film with an inorganic photorefractive material. In order to manufacture a new device from these photorefractive materials, structural requirements such as a multilayer structure cannot be satisfied at all. In order to overcome these problems, the present invention provides a photorefractive material using a novel composition that combines an inorganic photorefractive material with another matrix.

It is a novel invention to disperse an inorganic photorefractive crystal in an organic polymer or glass to enable the photorefractive effect. In the present invention, various compositions described below are formed in various mixing ratios. The present invention is characterized in that a ferroelectric having oxygen octahedron structure, silenite, and a semiconductor crystal are embedded in various insulating matrices.

Bulk or nanoparticles are used in the composition of the present invention. Through experiments, various compositions belonging to the present invention were found that were easy to mold and could be processed into the required shapes. (1) In the first method, the inorganic photorefractive crystal is mixed with a known polymer by an organic solvent treatment.
(2) In the second method, the powder of the photorefractive crystal is mixed with the silicate glass by the melting process by the melting process and molded into a transparent rod. (3) The photorefractive crystal is mixed with other metal, inorganic or organic compound by physical means. A composition based on a completely different interaction can be obtained by these various kinds. It was also observed that the formation of the composition significantly increased the photorefractive response. The present invention provides a simple molding and processing method of a photorefractive medium applicable to various devices in the field of photonics.

Organic compositions are important and interesting materials both in terms of chemistry and unique physics associated with material science.

The object of the present invention is to provide a photorefractive material exhibiting a large electro-optic effect and photoconductivity, or an inorganic photorefractive material and an organic polymer, glass, metal or inorganic semiconductor which is a novel composition for photonics technology. , To provide compositions with ferroelectrics or organic supramolecules.

The composition of the present invention using an inorganic photorefractive material has excellent mechanical or thermal characteristics, and exhibits excellent environmental resistance and scientific stability. Furthermore, they have good adhesion and can be processed into ultra thin films. The composition of the present invention is far superior to conventional inorganic or organic compositions in physical properties in that it can be easily processed, molded or chemically modified and is stable for a long period of time.

Another object of the present invention is to provide a composition material for photonics and electronics which has good processability, mechanical strength and thermal and environmental stability. Further, it is an object of the present invention to provide a photorefractive material composition having durability, strength and stability, which can be applied as a nonlinear optical material.

Another object of the present invention is to provide a photorefractive medium exhibiting a high electro-optic constant and photoconductivity.

Another object of the present invention is to provide a photorefractive material which is easy to synthesize, has processability, high mechanical strength and stability.

Another object of the present invention is to provide a fullerene LB film applicable to electronics and photonics.

Another object of the present invention is to provide a composition structure dispersed in various organic and inorganic matrices applicable to electronics and photonics devices.

The objects of the present invention are achieved by the novel electronics and non-linear optical media of photorefractive compositions dispersed in organic polymers, mixed with metals or combined with glass. These compositions can be easily controlled by adjusting the stoichiometric ratio of the dispersion medium and the crystals.

[0016]

The present invention solves the conventional problems by the means described below. The present invention is a photorefractive material composition comprising an inorganic photorefractive material dispersed in another material. The present invention is also a photorefractive device characterized by using an inorganic photorefractive material dispersed in another material.

The present invention is characterized by the following novel compositions.

In a photorefractive material composition in which an inorganic photorefractive material is mixed in a non-conjugated polymer, the non-conjugated polymer is polystyrene, polybutylene terephthalate, polyethylene, polypropylene, fluoropolymer, polyvinylcarbazole, polyvinylacetate, polychlorinated. Photorefractive material composition characterized by being selected from any of vinyl, nylon, polyester, phenolic resin, epoxy resin, polyacrylate, butadiene rubber, polyimide, polyether, polyurethane, polycarbonate, polyvinylamine and the like. .

In a photorefractive material composition in which an inorganic photorefractive material is mixed in a piezoelectric or ferroelectric organic polymer, the piezoelectric or ferroelectric organic polymer is polyvinylidene chloride, cyano polymer, polyurea, A photorefractive material composition, which is selected from any of polythiourea, odd-numbered nylon, and copolymers of these polymers.

A photorefractive material composition in which an inorganic photorefractive material is mixed in a liquid crystalline polymer.

A photorefractive material composition in which an inorganic photorefractive material is mixed with a polymer or a polymer mixture having photoconductivity.

In a photorefractive material composition in which an inorganic photorefractive material is mixed in a π-conjugated organic polymer, the π-conjugated organic polymer is a polyheterocyclic polymer, polyphenylenevinylene, polythienylvinylene, polyphthalocyanine, polysilane, A photorefractive material composition, which is selected from any one of polydiacetylene, polyazine, polyazomethine, poly-p-phenylene flufide, poly-p-phenylene, a heterocyclic ladder polymer and polyaniline.

In a photorefractive material composition in which an inorganic photorefractive material is mixed with an organic aromatic compound, the organic aromatic compound is a metal phthalocyanine,
A photorefractive material composition, which is selected from any one of porphyrin, TCNQ, TTF, a benzene substitution product, perylene, stilbene, azobenzene, benzylidene, acridine, fluorene, a heterocyclic compound and tinolin.

In a photorefractive material composition in which an inorganic photorefractive material is mixed in an inorganic polymer, the inorganic polymer is one of polysulfanilide, polysilicate, polyphosphazene, polyphosphate and polyborazine. A photorefractive material composition characterized by being selected.

A photorefractive material composition in which an inorganic photorefractive material is mixed in an organometallic polymer.

A photorefractive material composition obtained by mixing an inorganic photorefractive material with a metal selected from alkali metals, transition metals and alloys thereof.

A photorefractive material composition comprising an inorganic photorefractive material embedded in a lattice of a salt of a metal selected from alkali metals, transition metals and alloys thereof.

In a photorefractive material composition in which an inorganic photorefractive material is mixed in an inorganic glass, the glass is selected from silicate, borosilicate, lead-tin fluorosilicate glass and the like. Photorefractive material composition.

An electro-optical element, a laser wavelength conversion element, characterized by using a photorefractive material composition,
Optoelectronic switch, spatial light modulator, phase-locked structure laser, four-wave mixing device, photolithography device, image disturbance calibration device, optical filter, optical memory device, optical logic gate, optical computing device, holographic device, optical homodyne communication A device, a phase conjugation device, an optical amplification device, an optical bistable element, an optical resonant element, an optical oscillating element, a ferroelectric particle or a semiconductor element is also included in the scope of the present invention.

The composition of the present invention using an electro-optic crystal is
A continuous solid-phase film having a thickness of 0.1 to 500 μ can be formed by a conventionally known method such as spin coating or molding. The molecular composition structure of the composition of the present invention can be controlled by the selection and type of dispersion medium. The composition of the present invention exhibits good heat resistance and chemical stability.

The photorefractive measurement of the composition of the present invention is carried out depending on the application such as two-light beam coupling and degenerate four-wave mixing.

The present invention can be further embodied to provide a photorefractive composition exhibiting great photorefractive properties. The response time can be selected in the range of milliseconds to subpicoseconds according to the type of composition. The photorefractive characteristics change significantly depending on the amount of the photorefractive material mixed in the dispersion medium. By further developing the present invention, the fullerene nanoparticles can be applied as a quantum dot lattice that enables amplification of photorefractive characteristics based on an increase in exciton coherence length due to cooperative interaction of a large number of quantum dots. We evaluated the photorefractive properties of quantum dot lattices composed of organic polymers and electro-optic materials, and observed that they were several orders of magnitude better than other materials. Glasses doped with photorefractive materials exhibited exceptionally high photorefractive properties due to the increased lifetime due to contributions from both the bulk and surface due to the photorefractive molecules being placed in a glassy environment. Furthermore, glasses doped with photorefractive materials provide a convenient system for observing photorefractive phenomena at relatively low input.

[0033]

Since the present invention is constituted in this way, a high-performance photorefractive composition superior to conventional ones is provided and can be suitably used for various optical applications.

[0034]

EXAMPLES The effects of the present invention will be described in more detail below with reference to examples.

Example 1 2 g of polymethylmethacrylate (PMMA) was dissolved in toluene and stirred. To this, 20 mg of barium titanate powder was added, and the mixed solution was further stirred for 3 to 4 hours. A thin film of the composition of the present invention was obtained by spin-coating the substrate with the solution.

Example 2 1 g of vinylidene fluoride-trifluoroethylene copolymer was dissolved in MEK and stirred. To this was added 10 mg of KNbO ₃ and the mixed solution was stirred for another 5 hours. A film of the composition of the present invention was produced by spin coating. Similarly, with a benzene solution,
A composition of the present invention using polystyrene was prepared.

(Example 3) 1 g of ferroelectric polyurea was added to T
It was dissolved in HF and stirred at room temperature. Add 10 mg of BSO to this
Was added and the mixed solution was stirred for another 2 hours. A transparent, flexible film of the composition of the invention was prepared by solvent evaporation.

Example 4 2 g of nylon-66 was added to 90
% Formic acid at room temperature, 20 mg of BSO nanoparticles were added thereto, and the mixed solution was further stirred at room temperature for 2 to 3 hours. A film of the composition of the present invention was prepared from this dispersion.

(Example 5) Amorphous nylon (trade name: Zyte
1330) was dissolved in methanesulfonic acid at 2.5% by weight, barium niobate / potassium (BNN) was added thereto, and the mixed solution was further stirred at room temperature under reduced pressure for several days until it became homogeneous. The composition film of the present invention was prepared by extrusion and the residual acid was washed with a trace amount of water. From this dispersion a film of the composition of the invention of optical quality was prepared, which was good enough for photorefractive measurements. (Example 6) Molten lead-tin fluorophosphate glass (L
BaTiO ₃ crystallites (powder) were added to the TF) slurry with vigorous stirring. The composition of this LTF glass is Pb
F ₂ (5.1% mol), SnF ₂ (52.2% mol), SnO
(10.5% mol) and P ₂ O ₅ (32.1% mol).
The mixture was heated to 400 ° C. in a carbon crucible and after the initial melting reaction was complete, 3.0 mg BaTiO ₃ was added and mixed thoroughly. During this process, BaTiO ₃ was incorporated into the LTF glass. The transparent film of the present invention contains 300
It was prepared by sandwiching it between two glass plates that had been cooled to ℃ and preheated. LTF glass is characterized by its low melting point. The LTF-BaTiO ₃ composition thus prepared exhibited high transparency, chemical stability, good gloss, durability and hardness.

Example 7 2 g of an inorganic polymer, poly (phospharus nitrile chloride), was dissolved in 25 ml of benzene, and 10 mg of SBN was added thereto. The mixed solution was stirred at room temperature for 6 hours. An ultrathin film of the composition of the present invention was prepared from this dispersion. Similarly, a composition of the present invention using poly (diphenylphosphazene) was prepared using a warm benzene solution.

Example 8 1 g of poly (3-dodecylthiophene) was dissolved in 5 ml of toluene, and 10 mg of SBN was added thereto. The mixed solution was vigorously stirred at room temperature for several hours. A film of the composition of the present invention was prepared from this dispersion by solvent evaporation. Similarly, compositions of the present invention were prepared using various poly (3-alkylthiophenes) in which the alkyl groups were butyl, hexyl and octyl.

Example 9 Poly (7-oxo-7,10
H-benz-imidazo "4 ', 5': 5,6] -benzimidazo [2,1-a] isoquinoline-3,4: 10,
11-Tetrayl-10carbonyl) (abbreviation BBL) was added to 1,2,4,5-tetraaminobenzene and 1,4,5,5.
8-Naphthalenetetracarboxylic acid was synthesized by condensation reaction in nitrogen-degassed polyphosphoric acid. Heteroconjugate BB
The L polymer slurry was filtered from a methanol solution and dissolved in methanesulfonic acid. Add 5 mg of InP to this,
The mixture was vigorously stirred at room temperature for 3 hours. A film of the composition of the present invention was prepared by applying the mixed solution, vacuum drying at 150 ° C., and washing the acid residue with water. The film produced by solvent evaporation at high temperature showed high tensile strength and excellent heat resistance even in an oxidizing atmosphere. Similarly, a composition of the present invention using another photorefractive material and a polymer was prepared.

[0043]

According to the present invention, a high-performance photorefractive composition superior to conventional ones is provided and can be suitably used for various optical applications.

Claims (2)

[Claims] 1. A photorefractive material composition comprising an inorganic photorefractive material dispersed in another material. 2. A photorefractive device using an inorganic photorefractive material dispersed in another material.