JP2005227376A - Organic nonlinear optical material and nonlinear optical element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic nonlinear optical material to which a polymer binder having high glass transition temperature can be effectively applied and which has both excellent nonlinear optical performance and excellent stability by using an organic compound excellent in amorphous properties oxidation resistance, sublimation resistance and the like and having a specific nonlinear optical activity, and to provide a nonlinear optical element using the same. <P>SOLUTION: The organic nonlinear optical material formed by dispersing or bonding the organic compound having the nonlinear optical activity in or to the polymer binder is characterized in that the organic compound having the nonlinear optical activity contains at least one kind of tertiary amine derivatives represented by general formula (1). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is applied to an optical modulator, an optical switch, an optical integrated circuit, an optical computer, an optical memory, a wavelength conversion element, a holographic element, etc. useful in the fields of optical information communication using light, optical information processing, imaging, etc. The present invention relates to a non-linear optical element. Furthermore, this invention relates to the organic nonlinear optical material required in order to produce the said nonlinear optical element.

  Many of the functional elements such as wavelength conversion elements, optical modulators, and optical switches that are important in the fields of optical information communication, optical information processing, and imaging using light use nonlinear optical materials, particularly second-order nonlinear optical materials. Is embodied by. As the second-order nonlinear optical material, inorganic nonlinear optical materials such as lithium niobate and potassium dihydrogen phosphate have already been put into practical use and widely used. Organic nonlinear optical materials having advantages such as performance, inexpensive materials, manufacturing costs, and high manufacturability have attracted attention, and active research and development for practical application is being conducted.

  The second-order nonlinear optical effect is indispensable in principle that there is no symmetry center in the system, and a system in which an organic compound having nonlinear optical activity is crystallized into a crystal structure having no symmetry center (hereinafter referred to as “crystal”). And a system in which an organic compound having nonlinear optical activity is dispersed or bonded to a polymer binder and the organic compound having nonlinear optical activity is oriented by some means (hereinafter referred to as “polymer system”). ).

  The crystalline organic nonlinear optical material is known to exhibit very high nonlinear optical performance, but it is difficult to produce a large organic crystal necessary for device formation, and the strength of the organic crystal is extremely high. It is brittle and has problems such as damage in the device fabrication process. In contrast, the polymer-based organic nonlinear optical material is provided with favorable properties such as film formability and mechanical strength that are useful for device formation due to the polymer binder, and has potential for practical use. Is highly promising.

  In the polymer organic nonlinear optical material, it is required that an organic compound having nonlinear optical activity is uniformly dispersed or bonded in the polymer binder without agglomeration and becomes optically homogeneous and transparent. Furthermore, as described above, in order to exhibit the second-order nonlinear optical effect, an organic compound having nonlinear optical activity must be oriented by some means to impart anisotropy, and can be used as a functional element. In this case, the orientation state must be maintained stably over a long period of time in a temperature and humidity environment where the element is placed.

  Therefore, an organic compound having nonlinear optical activity used for a polymer organic nonlinear optical material is required to have low cohesiveness and excellent compatibility with a polymer binder in addition to high nonlinear optical performance. In addition, a high molecular weight organic nonlinear optical material is generally formed into an element in the form of a thin film, and a wet coating method is suitably used as a method for forming the thin film. For this reason, the organic compound having nonlinear optical activity used for the polymer organic nonlinear optical material is required to have high solubility in a coating solvent. On the other hand, the polymer binder is required to have a high glass transition temperature in order to stably maintain the orientation state of the organic compound having nonlinear optical activity to be included, in addition to high film formability and mechanical strength.

  Further, in order to cause the second-order nonlinear optical activity in the polymer organic nonlinear optical material, it is necessary to align the organic compound having nonlinear optical activity as described above. In general, an electric field poling method is used. The electric field poling method is an alignment method in which an electric field is applied to a nonlinear optical material, and the nonlinear optically active compound is aligned in the applied electric field direction by the Coulomb force between the dipole moment of the nonlinear optically active compound and the applied electric field. In addition to applying an electric field, heating is performed to a temperature near the glass transition temperature of the organic nonlinear optical material to promote molecular movement of the nonlinear optically active compound and to assist orientation.

  Examples of the organic compound having nonlinear optical activity include Disperse Red 1 (generally abbreviated as DR1), 4- (Dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (generally abbreviated as DCM). Are well known (see, for example, Non-Patent Document 1).

  On the other hand, polymethylmethacrylate (generally abbreviated as PMMA) has been most studied as the polymer binder, but the glass transition temperature of PMMA is as low as about 100 ° C., and PMMA is used as a polymer binder. It is known that the orientation state of molecular organic nonlinear optical materials gradually relaxes even at room temperature, and the nonlinear optical performance deteriorates remarkably over time, so that it cannot be put into practical use as a functional element (for example, Non-Patent Document 2).

  In order to solve this problem, a search for a polymer binder that replaces PMMA has been actively conducted, and the effectiveness of a polymer having a glass transition temperature higher than that of PMMA such as polycarbonate, polyimide, and polysulfone has been reported ( For example, refer to Patent Document 1), when these polymer binders having a high glass transition temperature are used, the heating temperature required at the time of electric field poling also rises, and the above-mentioned DR1 and DCM are used as organic compounds having nonlinear optical activity. When these are used, there is a problem that these low-molecular compounds are lost by sublimation or oxidized.

In addition, the compatibility between these polymer binders having a high glass transition temperature and the above-mentioned DR1 and DCM is not always good, and when they are added at a high concentration in order to improve the nonlinear optical performance, they aggregate or crystallize. In addition, there is a problem that even at a low concentration, aggregation or crystallization occurs due to heating or aging.
Chemistry of Materials, 1999, 11, 25554-2561 Chemical Reviews, 1994, 94, 1, 31-75 JP-A-6-202177

The object of the present invention is to solve the problems of the prior art as described above.
That is, the present invention can effectively utilize a polymer binder having a high glass transition temperature by using an organic compound having specific nonlinear optical activity excellent in amorphousness, oxidation resistance, sublimation resistance, etc. It is an object of the present invention to provide an organic nonlinear optical material having both nonlinear optical performance and excellent stability, and a nonlinear optical element using the organic nonlinear optical material.

  In order to solve the above problems, the present inventors have conducted extensive studies on organic compounds having nonlinear optical activity and polymer binders, and as a result, by utilizing organic compounds having specific nonlinear optical activity, The present inventors have found that the problems can be solved and have completed the present invention.

That is, the present invention
<1> An organic nonlinear optical material obtained by dispersing or bonding an organic compound having nonlinear optical activity in a polymer binder, wherein the organic compound having nonlinear optical activity is a tertiary compound represented by the following general formula (1) An organic nonlinear optical material comprising at least one amine derivative.

In the above formula, R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group; X ^{1 to} X ⁴ are each independently a hydrogen atom, a halogen atom, or an alkyl Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group, and at least one of them is a hydrocarbon group or methyl group that is bulkier than a methyl group. Is a bulky heteroatom-containing hydrocarbon group; Z ³ is a substituted or unsubstituted aromatic group; L is a π-conjugated group which may have a substituent; and A has a substituent. An electron withdrawing group; m represents 0 or 1; Z ¹ and R ¹ or R ² and Z ² and R ³ or R ⁴ may be connected to each other to form a ring structure. Further, any of X ^{1 to} X ⁴ and Z ³ may be linked to form a ring structure.

<2> In the tertiary amine derivative represented by the general formula (1), Z ¹ may be linked to R ¹ or R ² , Z ² may be linked to R ³ or R ⁴ , and Z ¹ and / or <2> The organic nonlinear optical material according to <1>, wherein Z ² is a hydrocarbon group having a ring structure or a heteroatom-containing hydrocarbon group having a ring structure.

<3> The organic nonlinear optics according to <2>, wherein Z ¹ and / or Z ² in the tertiary amine derivative represented by the general formula (1) is a substituted or unsubstituted aromatic group. Material.

<4> The tertiary amine derivative represented by the general formula (1) is a triarylamine derivative represented by the following general formula (2), according to any one of <1> to <3> Organic nonlinear optical material.

In the above formula, Y ¹ and Y ² are each independently N or CH, and M is a π-conjugated group having a ring structure which may have a substituent. R ^{1 to} R ⁴ , Z ¹ , Z ² and A are the same as those in the general formula (1).

<5> A in the tertiary amine derivative represented by the general formula (1) is any one of a nitro group; a cyano group; an electron-withdrawing π-conjugated group having at least a nitro group and / or a cyano group. The organic nonlinear optical material according to any one of <1> to <4>.

<6> The organic nonlinear optical material according to any one of <1> to <5>, wherein the polymer binder contains at least one of polyimide, polycarbonate, polyarylate, and polycyclic olefin. is there.

<7> A nonlinear optical element using the organic nonlinear optical material according to any one of <1> to <6>.

  The organic nonlinear optical material of the present invention is obtained by dispersing or bonding an organic compound having a specific nonlinear optical activity excellent in amorphousness, heat resistance, and sublimation resistance to a polymer binder having a high glass transition temperature. Even if organic compounds having nonlinear optical activity at a high concentration are present in the material, they do not aggregate and take a uniform dispersion state. Therefore, both high optical quality and nonlinear optical activity are combined. The organic compound having activity has high thermal stability in the alignment state and stability over time, and has preferable effects such as maintaining excellent characteristics over a long period of time. For this reason, by using the organic nonlinear optical material of the present invention, a nonlinear optical element having excellent characteristics and stability can be realized.

Hereinafter, the present invention will be described in detail according to embodiments.
<Organic nonlinear optical material>
The organic nonlinear optical material of the present invention is an organic nonlinear optical material obtained by dispersing or bonding an organic compound having nonlinear optical activity in a polymer binder, and the organic compound having nonlinear optical activity is represented by the following general formula (1). And at least one tertiary amine derivative represented by the formula:

In the above formula, R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group; X ^{1 to} X ⁴ are each independently a hydrogen atom, a halogen atom, or an alkyl Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group, and at least one of them is a hydrocarbon group or methyl group that is bulkier than a methyl group. Is a bulky heteroatom-containing hydrocarbon group; Z ³ is a substituted or unsubstituted aromatic group; L is a π-conjugated group which may have a substituent; and A has a substituent. An electron withdrawing group; m represents 0 or 1; Z ¹ and R ¹ or R ² and Z ² and R ³ or R ⁴ may be connected to each other to form a ring structure. Further, any of X ^{1 to} X ⁴ and Z ³ may be linked to form a ring structure.

  The tertiary amine derivative represented by the general formula (1) has a triarylamine structure and a substituent that is higher than a methyl group, and is designed to be very bulky in terms of molecular structure. It has excellent chemical stability such as heat resistance, oxidation resistance, and light resistance, is highly amorphous, and exhibits excellent compatibility with various polymer binders. Furthermore, the sublimation temperature is very high, and the above-described problem of sublimation during electric field poling can be avoided.

  That is, in a so-called push-pull type π-conjugated nonlinear optically active organic compound having an electron-donating group at one end of a π-conjugated chain and an electron-withdrawing group at the other end, as defined in the present invention, By binding an electron-donating group having a bulky (bulky) substituent, the associating property of the molecule is reduced and the amorphous property is increased, and the sublimation temperature can be increased by increasing the molecular weight. . At the same time, stability such as heat resistance can be improved.

(Organic compound having nonlinear optical activity)
Hereinafter, first, the organic compound having nonlinear optical activity used in the present invention will be described.
As described above, the organic compound having nonlinear optical activity used in the present invention is a tertiary amine derivative represented by the general formula (1). R ^{1 to} R ⁴ in the tertiary amine derivative are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group, preferably a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, Or it is an aryloxy group. X ^{1 to} X ⁴ are each independently a hydrogen atom, a halogen atom or an alkyl group, preferably a hydrogen atom.

Further, Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group, and at least one of them is a bulky (bulky) hydrocarbon group than a methyl group Or a heteroatom-containing hydrocarbon group that is bulkier (bulky) than a methyl group.
In this way, by bonding a bulky substituent as Z ¹ and / or Z ² , the whole organic compound having nonlinear optical activity can be made into a large structure.

  Examples of the hydrocarbon group that is bulky than the methyl group or the heteroatom-containing hydrocarbon group that is bulky than the methyl group include a hydrocarbon group having 2 or more carbon atoms and a heteroatom-containing hydrocarbon group having 1 or more carbon atoms. Correspondingly, preferably, a substituted or unsubstituted alkyl group having 2 or more carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group and the like can be mentioned. More preferred is a hydrocarbon group having a ring structure or a heteroatom-containing hydrocarbon group having a ring structure, and more preferred is a substituted or unsubstituted aromatic group.

Z ³ is a substituted or unsubstituted aromatic group, preferably a substituted or unsubstituted 1,4-phenylene group, and more preferably an unsubstituted 1,4-phenylene group.

  L is an arbitrary π-conjugated group which may have a substituent, preferably a π-conjugated group not containing an aliphatic unsaturated group that is not adjacent to an aromatic group, and more preferably substituted with an azo group or It is a π-conjugated group consisting only of an unsubstituted 1,4-phenylene group.

  A is any electron-withdrawing group which may have a substituent, preferably a nitro group; a cyano group; a fluorine atom-containing alkyl group; a fluorine atom-containing aryl group; a substituted or unsubstituted alkyl sulfonic acid group; And a π-conjugated group containing one or more thereof; and the like.

In the present invention, Z ¹ and R ¹ or R ² and Z ² and R ³ or R ⁴ may be linked to each other to form a ring structure. In addition, any of X ^{1 to} X ⁴ and Z ³ may be linked to form a ring structure.

  Among the tertiary amine derivatives represented by the general formula (1), the triarylamine derivative represented by the following general formula (2) is particularly preferable in terms of ease of synthesis, chemical stability, nonlinear optical performance, and the like. preferable.

Specific examples of the organic compound having nonlinear optical activity that can be suitably used in the present invention include the following. In these, “Me” represents a methyl group, and “ ^t Bu” represents a tertiary butyl group.

  As a method for synthesizing the tertiary amine derivative represented by the general formula (1), any arbitrary method can be used. For example, a method of dehydrating and condensing a corresponding formyl compound and an electron-withdrawing compound having an active methyl group in the presence of a base as shown below is useful. As a method for synthesizing the formyl compound, a formylation method such as the Vilsmeier method can be used. As a method for synthesizing an electron-withdrawing compound having an active methyl group, `` Synthetic Communications, 1995, 25, 19, 3045-3051 '', `` Chemistry of Materials, 2002, 14, 2393-2400 '' Etc. can be used.

  The sublimation temperature of the organic compound having nonlinear optical activity used in the present invention described above is preferably 130 ° C. or higher, and more preferably 170 ° C. or higher.

  In addition, as described above, the organic compound having nonlinear optical activity used in the present invention is required to have excellent solubility in a solvent of a coating solution when an organic nonlinear optical material is produced. The solubility is, for example, preferably 1% by mass or more and more preferably 5% by mass or more in a solvent such as tetrahydrofuran, cyclopentanone, chloroform, N, N-dimethylacetamide at room temperature. .

Furthermore, the electro-optic constant of the organic compound having nonlinear optical activity used in the present invention is preferably 1 pm / V or more, and more preferably 10 pm / V or more.
The electro-optic constant can be measured by a measuring method such as a normal ATR method or ellipso reflection method.

(Polymer binder)
The polymer binder used in the present invention may be any as long as it is excellent in optical quality and film formability, but preferably has a glass transition temperature of 150 ° C. or higher. Particularly preferably, the glass transition temperature is 170 ° C. or higher and the mechanical strength is high, and specific examples include polyimide, polycarbonate, polyarylate, and polycyclic olefin.

  In the present invention, a differential scanning calorimeter (DSC) is used to measure the glass transition temperature of the polymer binder and the organic nonlinear optical material described later, and is measured from room temperature at a heating rate of 10 ° C. per minute. The temperature corresponding to the intersection of the slope of the rising end of the endothermic process accompanying the glass transition and the baseline was taken as the glass transition temperature.

  The organic nonlinear optical material of the present invention is formed from at least the organic compound having nonlinear optical activity and a polymer binder. The organic compound having nonlinear optical activity may be dispersed in a molecular state in the polymer binder, or may be chemically linked to the side chain or main chain of the polymer binder.

  The form of the organic nonlinear optical material of the present invention may be any form, but it is generally used in the form of a thin film for application to a nonlinear optical element. As a method for producing a thin film containing the organic nonlinear optical material of the present invention, known methods such as an injection molding method, a press molding method, a soft lithography method, a wet coating method, etc. can be used. From the viewpoint of mass productivity, film quality (thickness uniformity, few defects such as bubbles), etc., a solution in which at least the above organic compound having nonlinear optical activity and a polymer binder are dissolved in an organic solvent is used. A wet coating method in which a film is formed by coating on an appropriate substrate by a method such as a spin coating method, a blade coating method, a dip coating method, or an ink jet method is preferable.

  The organic solvent used in the wet coating method may be any organic solvent that can dissolve the organic compound having nonlinear optical activity and the polymer binder, and has a boiling point in the range of 50 to 200 ° C. Is preferred. If an organic solvent with a boiling point of less than 50 ° C is used, solvent volatilization will occur during storage of the coating solution, and the viscosity of the coating solution will change (increase), or the solvent will volatilize too quickly during coating and condensation may occur. There is a tendency for problems such as looseness to become prominent. On the other hand, when an organic solvent having a boiling point exceeding 200 ° C. is used, it is difficult to remove the solvent after coating, and the remaining organic solvent acts as a plasticizer for the polymer binder, causing problems such as reducing the glass transition temperature. There is.

  Examples of preferred organic solvents include tetrahydrofuran, methyltetrahydrofuran, dioxane, diethylene glycol dimethyl ether, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl acetate, cyclohexanol, dichloroethane, chloroform, toluene, chlorobenzene, xylene, N, N-dimethylformamide, N , N-dimethylacetamide, dimethyl sulfoxide and the like. These organic solvents may be used alone or in combination.

  In the organic nonlinear optical material of the present invention, the content of the organic compound having nonlinear optical activity varies depending on the type of the organic compound having nonlinear optical activity to be used, the required nonlinear optical performance, mechanical strength, etc. In general, however, the ratio of the organic nonlinear optical material to the total mass is preferably in the range of 1 to 90% by mass. The reason is that if it is less than 1% by mass, sufficient nonlinear optical performance is often not obtained, and if it exceeds 90% by mass, problems such as insufficient mechanical strength tend to occur. It is. A more preferable range of the content of the organic compound having nonlinear optical activity is in the range of 10 to 75% by mass, and further preferably in the range of 25 to 60% by mass.

  The preferable content of the organic compound having nonlinear optical activity is the same regardless of whether the organic compound having nonlinear optical activity is dispersed in the polymer binder or bonded to the polymer binder. It is a range.

  In addition to the organic compound having a nonlinear optical activity and the polymer binder, various additives can be added to the organic nonlinear optical material of the present invention as necessary. For example, a known antioxidant such as 2,6-di-t-butyl-4-methylphenol and hydroquinone is used for the purpose of suppressing the oxidative degradation of the organic compound and / or polymer binder having nonlinear optical activity. For the purpose of suppressing ultraviolet degradation of the organic compound or polymer binder having optical activity, known ultraviolet absorbers such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone can be used.

  When wet coating is performed, a known leveling agent such as silicone oil is used in the coating solution for the purpose of improving the surface smoothness of the coating film, or a non-linear optically active organic compound having a crosslinking curable functional group. When using a compound or a polymer binder, a known curing catalyst or curing aid may be added for the purpose of accelerating the crosslinking and curing.

The organic nonlinear optical material of the present invention is produced by using the coating liquid produced as described above and forming it as a thin film by, for example, the spin coating method described above. As described above, in the present invention, a polymer binder having a relatively high glass transition temperature is used. However, an organic nonlinear optical material containing a prepared organic compound having nonlinear optical activity can also be used from the viewpoint of heat resistance and the like. A high glass transition temperature is desirable.
Therefore, the glass transition temperature of the organic nonlinear optical material is preferably 130 ° C. or higher, and more preferably 150 ° C. or higher.

  In order to generate the second-order nonlinear optical activity in the polymer-based nonlinear optical material, it is necessary to orient the organic compound having the nonlinear optical activity as described above. As an alignment method for this purpose, a non-linear optical activity in a high-molecular non-linear optical material is applied by applying a high-molecular non-linear optical material on a substrate having an alignment film on the surface, and depending on the orientation of the substrate alignment film. There is a method for inducing the orientation of an organic compound having s. Also, known polling methods such as an optical poling method, an optically assisted electric field poling method, and an electric field poling method can be used effectively. Among these, the electric field poling method is particularly preferable in terms of the simplicity of the apparatus and the high degree of orientation obtained.

  The electric field poling method is largely classified into a contact poling method in which a nonlinear optical material is sandwiched between a pair of electrodes and an electric field is applied, and a corona poling method in which a corona discharge is applied to the surface of the nonlinear optical material on the substrate electrode and a charging electric field is applied. Separated. The electric field poling method is an alignment method in which the nonlinear optically active compound is aligned (polled) in the direction of the applied electric field by the Coulomb force between the dipole moment of the nonlinear optically active compound and the applied electric field.

  In the electric field poling method, generally, by applying an electric field and heating to a temperature in the vicinity of the glass transition temperature of the nonlinear optical material, the alignment movement in the electric field direction of the nonlinear optically active compound is promoted and sufficient alignment is achieved. After the induction, the applied electric field is removed after cooling to room temperature with the electric field applied and freezing the alignment state. However, since this orientation state is basically a thermodynamic nonequilibrium state, even if the temperature is lower than the glass transition temperature, it is gradually randomized over time, and the fundamental problem is that nonlinear optical activity decreases. Have

  The randomization of the orientation state over time progresses more gradually as the difference between the environmental temperature where the nonlinear optical material is placed and the glass transition temperature is larger. By raising the glass transition temperature, this problem can be substantially solved in actual use. In the present invention, a polymer binder having a glass transition temperature of 130 ° C. or higher is preferably used. However, even in this case, the sublimation temperature of the organic compound having nonlinear optical activity used in the present invention is high as described above. It is possible to produce a nonlinear optical material excellent in nonlinear optical performance and stability without sublimation or deterioration during heating.

  As an index for confirming whether or not the polling is performed, there is a numerical value (order parameter: φ) indicating how many nonlinear optical molecules (generally having dichroism) are oriented in the electric field direction. Specifically, when the absorbance when the orientation of the molecules is random is A0 and the absorbance when oriented in the electric field direction (film thickness direction) is At, φ is 1- (At / A0). It can be calculated.

  The order parameter is a numerical value that is 1 in an ideal state in which all molecules are perfectly oriented, and 0 when completely random, and indicates that the larger the value, the higher the degree of molecular orientation as a whole. By measuring this value, it can be determined how efficiently polling has been performed, and its stability can be evaluated.

<Nonlinear optical element>
The nonlinear optical element of the present invention is characterized by utilizing the organic nonlinear optical material of the present invention and may be any element that operates based on the nonlinear optical effect. Specific examples thereof include, for example, a wavelength conversion element. , Photorefractive elements, electro-optical elements, and the like. Particularly preferable are electro-optical elements such as an optical switch, an optical modulator, and a phase shifter that operate based on a nonlinear optical effect.

The electro-optical element is preferably used as an element having a structure in which a nonlinear optical material is formed on a substrate and sandwiched between electrode pairs for input electric signals.
As a material constituting such a substrate, metals such as aluminum, gold, iron, nickel, chromium, and titanium; semiconductors such as silicon, titanium oxide, zinc oxide, and gallium-arsenic; glass; polyethylene terephthalate, polyethylene naphthalate, Plastics such as polycarbonate, polysulfone, polyetherketone, polyimide, etc. can be used.

A conductive film may be formed on the surface of these substrate materials. Examples of the material of the conductive film include metals such as aluminum, gold, nickel, chromium, and titanium; tin oxide, indium oxide, ITO ( Conductive oxides such as tin oxide-indium oxide composite oxide) and IZO (indium oxide-zinc oxide composite oxide); The conductive film is formed using a known dry film formation method such as vapor deposition or sputtering, or a known wet film formation method such as dip coating or electrolytic deposition, and a pattern may be formed as necessary. It should be noted that the conductive substrate or the conductive film formed on the substrate as described above is an electrode (hereinafter referred to as a “lower electrode”) during polling or operation as an element. Abbreviated as ") is used as.

  The substrate surface is further provided with an adhesive layer for improving the adhesion between the film formed on the substrate and the substrate, a leveling layer for smoothing irregularities on the substrate surface, or these functions, if necessary. Some intermediate layer provided in a lump may be formed. The material for forming such a film is not particularly limited, and examples thereof include acrylic resins, methacrylic resins, amide resins, vinyl chloride resins, vinyl acetate resins, phenol resins, urethane resins, vinyl alcohol resins, acetal resins, and the like. Known products such as a crosslinked product of zirconium chelate compound, titanium chelate compound, silane coupling agent and the like, and a co-crosslinked product thereof can be used.

  The electro-optical element which is the nonlinear optical element of the present invention is preferably formed to include a waveguide structure, and it is particularly preferable that the nonlinear optical material of the present invention is contained in the core layer of the waveguide.

  A clad layer (hereinafter abbreviated as “lower clad layer”) may be formed between the core layer containing the nonlinear optical material of the present invention and the substrate. The lower cladding layer may be any layer as long as it has a lower refractive index than the core layer and is not affected by the formation of the core layer. As such materials, UV curable or thermosetting resins such as acrylic, epoxy, and silicone; polyimide; glass; and the like are preferably used.

  After the core layer is formed using the nonlinear optical material of the present invention, a clad layer (hereinafter abbreviated as “upper clad layer”) may be further formed on the core layer in the same manner as the lower clad layer. As a result, a slab waveguide having a structure of substrate / lower cladding layer / core layer / upper cladding layer is formed.

  After forming the core layer, the core layer is patterned by a known method using a semiconductor process technology such as reactive ion etching (RIE), photolithography, electron beam lithography, etc. to form a channel type waveguide or a ridge type waveguide You can also Alternatively, a channel-type waveguide can be formed by changing the refractive index of the irradiated portion by patterning and irradiating a part of the core layer with UV light, an electron beam or the like.

  A basic electro-optic element is formed by forming an electrode (hereinafter referred to as “upper electrode”) for applying an input electric signal to the surface of the upper cladding layer in a desired region of the upper cladding layer. be able to.

  When forming a channel-type waveguide or a ridge-type waveguide as described above, the core layer pattern may be a known device structure such as a linear type, a Y-branch type, a directional coupler type, or a Mach-Zehnder type. It can be configured, and can be applied to known optical information communication devices such as an optical switch, an optical modulator, and a phase shifter.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.
<Example 1>
(Production of organic nonlinear optical materials)
A tolylamine derivative represented by the following general formula (2) represented by the following structural formula (A) on a glass substrate (2 cm × 2 cm) provided with a pair of gold parallel electrodes (distance between electrodes: 20 μm) on the surface 3 parts by mass of an organic compound (sublimation temperature: 200 ° C. or higher) having nonlinear optical activity, which is a kind of (tertiary amine derivative), and a polymer binder represented by the following structural formula (B) which is a kind of polycyclic olefin A solution prepared by dissolving 7 parts by mass (trade name: Arton, glass transition temperature: 170 ° C., manufactured by JSR Corporation) in 90 parts by mass of cyclopentanone (boiling point: 130 ° C.) was applied by spin coating, and 130 ° C. And dried for 1 hour to obtain a thin film 1 having a thickness of 0.1 μm.
The thin film 1 was very clear and the triarylamine derivative was uniformly dispersed. Moreover, the glass transition temperature of the thin film 1 was 130 degreeC.

  Next, with the electric field of 50 V / μm applied between the parallel electrode pairs, the thin film 1 was held at 130 ° C. for 30 minutes, and after cooling to room temperature while applying the electric field, the electric field was removed. . Regarding the deterioration with time of poling of the thin film 1, both the order parameter immediately after fabrication and the order parameter after storage in a dark place for 10 days were both 0.34, and it was confirmed that no orientation relaxation occurred.

  Note that the order parameter is for both the thin film A in which the nonlinear optically active compound is randomly oriented without performing the poling treatment and the thin film B in which the nonlinear optically active compound is oriented in the film thickness direction by the poling treatment. Then, immediately after the production of the thin film A and the thin film B, the absorption spectrum in the visible region is measured with a spectrophotometer (Hitachi, U-3000), and from the wavelength λmax at which the absorption of the thin film A and the thin film B is maximized, Calculated according to 1).

φ = 1−At / A0 Formula (1)
(In the formula (1), φ represents the order parameter, At represents the absorbance at the wavelength λmax of the polled thin film B, and A 0 represents the wavelength at the wavelength λmax of the thin film A not subjected to the polling treatment. Represents absorbance.)

(Evaluation of organic nonlinear optical materials)
When the thus obtained thin film 1 made of an organic nonlinear optical material subjected to electric field poling of the present invention is irradiated with semiconductor laser light having an oscillation wavelength of 1310 nm, a second harmonic of 655 nm can be observed, and nonlinearity is observed. It was confirmed that it functions effectively as an optical material. Furthermore, when the nonlinear optical material was kept in a high temperature environment of 65 ° C. for 10 days and then irradiated again with laser light, it was confirmed that second harmonics having the same intensity as the initial generation were generated.

Further, when the thin film after maintaining the high temperature environment was observed with an optical microscope, it was very clear, and it was confirmed that the triarylamine derivative was uniformly dispersed in the polycyclic olefin. Furthermore, assuming that the device is manufactured using this organic nonlinear optical material, the surface of the thin film 1 was soldered (thin film surface temperature: about 200 ° C.). There was no deformation.
From the above, it was found that the organic nonlinear optical material of the present invention has high heat resistance and stability over time.

<Comparative Example 1>
A thin film made of an organic nonlinear optical material was prepared in the same manner as in Example 1 except that the organic compound having nonlinear optical activity in Example 1 was changed to DCM (manufactured by Aldrich). As a result, a transparent and homogeneous film could not be obtained.

<Example 2>
(Production of organic nonlinear optical materials)
Instead of the organic compound having nonlinear optical activity in Example 1, the organic compound having nonlinear optical activity (sublimation temperature: one of the triarylamine derivatives represented by the general formula (2) represented by the following structural formula: Poly [Bisphenol A carbonate-co-4,4 '-(3,3,5-trimethylcyclohexylidene) diphenol carbonate] (Aldrich) which is a kind of polycarbonate instead of polycyclic olefin as a polymer binder A thin film 2 made of an organic nonlinear optical material subjected to electric field poling was produced in the same manner as in Example 1 except that the glass transition temperature: 200 ° C. manufactured by the company was used and the poling temperature was changed to 170 ° C.
The thin film 2 was very clear, and the triarylamine derivative was uniformly dispersed. Moreover, the glass transition temperature of the thin film 2 was 165 degreeC.

  As for the deterioration with time of poling of the thin film 2, both the order parameter immediately after fabrication and the order parameter after storage in the dark for 10 days were both 0.36, and it was confirmed that no orientation relaxation occurred. It was. Further, assuming that the device is manufactured using this organic nonlinear optical material, the surface of the thin film 2 was soldered (thin film surface temperature: about 200 ° C.). There was no deformation.

(Evaluation of organic nonlinear optical materials)
When the obtained thin film 2 was evaluated in the same manner as in Example 1, the same second harmonics could be observed, and it was confirmed that the thin film 2 functions effectively as a nonlinear optical material. Furthermore, even after holding in a high temperature environment of 65 ° C. for 10 days, it is possible to confirm the generation of secondary harmonics having the same strength as the initial stage, and when the thin film after holding the high temperature environment is observed with an optical microscope, It was very clear and it was confirmed that the triarylamine derivative was homogeneously dispersed in the polycarbonate.
From the above, it was confirmed that the nonlinear optical material has high heat resistance and stability over time.

<Comparative example 2>
A thin film of nonlinear optical material subjected to electric field poling was prepared in the same manner as in Example 2 except that the organic compound having nonlinear optical activity in Example 2 was changed to DR1 (sublimation temperature: 120 ° C.). Due to heating, DR1 sublimated and most of it disappeared.

<Example 3>
(Production of nonlinear optical elements)
On a glass substrate (2 cm × 2 cm) having an ITO conductive film as a lower electrode formed on the surface, UV curable acrylic resin (Norland, product name: NOA72) was applied by spin coating, and 100 mW / cm ^2. After being irradiated with UV light (high pressure mercury lamp manufactured by USHIO INC.) For 30 seconds, a heat treatment was performed at 120 ° C. for 30 minutes to form a lower cladding layer having a thickness of 2 μm.

  Next, a solution containing the polycarbonate used in Example 2 and the triarylamine derivative was applied to the surface of the lower clad layer by a spin coat method, and dried at 130 ° C. for 1 hour, and a core layer having a thickness of 2 μm. Formed. Further, the same UV curable acrylic resin as that of the lower cladding layer is formed on the surface of the core layer in the same manner as the lower cladding layer to form an upper cladding layer having a thickness of 2 μm, and the substrate / lower cladding layer / A slab waveguide having a structure of core layer / upper clad layer was produced.

  Next, a striped gold thin film (stripe width: 20 μm, stripe interval: 30 μm) was formed on the surface of the upper clad layer by using a normal photolithography method and a sputtering method to form an upper electrode.

  The sample obtained as described above is cut into a chip having a width of 5 mm by a dicer (manufactured by Disco), the cut surface is polished with sandpaper, and a non-linear optical element having a cross section shown in FIG. Produced.

(Evaluation of nonlinear optical elements)
Next, an electric field of 100 V / μm was applied between the upper electrode 16 and the lower electrode 12 of the nonlinear optical element, and an electric field poling process was performed at 170 ° C. for 30 minutes.
In order to confirm that the nonlinear optical element subjected to the electric field poling process functions as an electro-optical element, the electro-optical characteristics were evaluated by the evaluation system shown in FIG.

  In the evaluation system shown in FIG. 2, laser light (He-Ne laser, oscillation wavelength: 633 nm) that has passed through the half-wave plate and the polarizer 23a from the light source 21 is transmitted from one end face (left side in the figure) of the electro-optic element 28. Incident light is propagated through the core layer in the electro-optic element 28 and emitted from the other end face (the right side in the figure). The light passes through the pinhole 26 and the polarizer 23b having the same polarization plane as that of the light. The detector 27 is configured to detect. In the figure, reference numeral 24 denotes a lens.

  When the non-linear optical element produced as described above is installed as the electro-optical element 28 and an electric field is applied between the upper and lower electrodes by the power source 25 and the electric field intensity is changed from 0 V to 20 V, the electric field intensity increases. Along with this, the behavior that the detected light intensity decreases was confirmed. This is because the non-linear optical element has an electro-optic effect and optical modulation occurs, and this indicates that the non-linear optical element functions effectively as an optical modulator. Furthermore, when this nonlinear optical element was kept in a high temperature environment of 65 ° C. for 10 days and then subjected to the same evaluation, the same optical modulation characteristic as that in the initial stage could be confirmed. It was confirmed to have stability over time.

<Comparative Example 3>
In the production of the nonlinear optical element of Example 3, the nonlinear optical device having the structure shown in FIG. 1 was used in the same manner as in Example 3 except that the core layer was formed using the organic nonlinear optical material used in Comparative Example 2. An element was produced.

Next, the electric field poling process was performed in the same manner as in Example 3 except that the poling temperature in the evaluation of the nonlinear optical element of Example 3 was changed to 120 ° C. where DR1 sublimation was not significant.
Next, the nonlinear optical element subjected to the electric field poling treatment was evaluated in the same manner as in Example 3. As a result, almost no change was detected in the detected light intensity at the electric field intensity of 0V to 20V. As a result, it was confirmed that it does not function effectively. This is presumably because the poling temperature was set to be significantly lower than the glass transition temperature of the binder polymer in order to avoid the sublimation of DR1, so that sufficient orientation was not induced by the electric field poling treatment.

It is typical sectional drawing which shows an example of the nonlinear optical element of this invention. It is a schematic block diagram of the evaluation system of a nonlinear optical element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Glass substrate 12 Lower electrode 13 Lower clad layer 14 Core layer 15 Upper clad layer 16 Upper electrode 21 Laser light source 22 Half-wave plate 23a, 23b Polarizer (Glan-Thompson prism)
24 lens 25 power supply 26 pinhole 27 photodetector 28 electro-optic element

Claims (7)

An organic nonlinear optical material obtained by dispersing or binding an organic compound having nonlinear optical activity in a polymer binder, and a tertiary amine derivative represented by the following general formula (1) is used as the organic compound having nonlinear optical activity: An organic nonlinear optical material containing at least one kind.

(In the above formula, R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group; X ^{1 to} X ⁴ are each independently a hydrogen atom, a halogen atom, or Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group, and at least one of them is a hydrocarbon group or a methyl group that is bulkier than a methyl group. A bulkier heteroatom-containing hydrocarbon group; Z ³ is a substituted or unsubstituted aromatic group; L is a π-conjugated group which may have a substituent; and A has a substituent. M represents 0 or 1. Z ¹ and R ¹ or R ² , and Z ² and R ³ or R ⁴ are connected to each other to form a ring structure. In addition, any of X ^{1 to} X ⁴ and Z ³ are connected to form a ring structure. Structure may be formed.) In the tertiary amine derivative represented by the general formula (1), Z ¹ may be linked to R ¹ or R ² , Z ² may be linked to R ³ or R ⁴ , and Z ¹ and / or Z ² are The organic nonlinear optical material according to claim 1, which is a hydrocarbon group having a ring structure or a heteroatom-containing hydrocarbon group having a ring structure. 3. The organic nonlinear optical material according to claim 2, wherein Z ¹ and / or Z ² in the tertiary amine derivative represented by the general formula (1) is a substituted or unsubstituted aromatic group. The organic nonlinear optical material according to any one of claims 1 to 3, wherein the tertiary amine derivative represented by the general formula (1) is a triarylamine derivative represented by the following general formula (2). .

(In the above formula, Y ¹ and Y ² are each independently N or CH, and M is a π-conjugated group having a ring structure which may have a substituent. R ^{1 to} R ⁴ , Z ¹ , Z ² and A are the same as those in the general formula (1).)   A in the tertiary amine derivative represented by the general formula (1) is any one of a nitro group; a cyano group; and an electron-withdrawing π-conjugated group having at least a nitro group and / or a cyano group. The organic nonlinear optical material according to claim 1.   6. The organic nonlinear optical material according to claim 1, wherein the polymer binder contains at least one of polyimide, polycarbonate, polyarylate, and polycyclic olefin.   A nonlinear optical element using the organic nonlinear optical material according to claim 1.

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