JPH07225402A - Organic nonlinear optical material and optical functional element using the same - Google Patents

Abstract

PURPOSE:To obtain an org. nonlinear optical material having high nonlinear optical characteristics and excellent in transparency by using a specified compd. CONSTITUTION:This org. nonlinear optical material is made of a compd. represented by the formula, wherein at least one of Ar1 and Ar2 is an atomic group having an optionally substd. pi-electron conjugated structure, at least one of Ar1 and Ar1 may be an arom. hydrocarbon ring typified by benzene, naphthalene or anthracene, a hetero ring typified by benzoquinone, naphthoquinone, anthraquinone, pyrrole, imidazole, indole, quinoline or phenazine or a pi-conjugated atomic group suck as cinnamyl, and each of Ar1 and Ar2 may have an org. substituent selected from among nitro, cyano, isocyanate, carboxy, alkylsulfonyl, allylsulfonyl, etc., and halogen.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an organic nonlinear optical material and an optical functional element using the same.

[0002]

2. Description of the Related Art Non-linear optical materials are materials that exhibit a second-order and third-order non-linear response due to interaction with a strong electromagnetic field such as laser light. Harmonic generation, optical mixing, optical parametric oscillation, optical modulation, optical Since it has many element functions such as a switch, it has been attracting attention as a wavelength conversion element of a laser and an element for optical computing, which plays an important role in the field of optical communication. Above all, the development of a wavelength conversion element utilizing the second harmonic generation (SHG), which is one of the nonlinear optical effects, has been actively pursued.

Conventionally, non-linear optical materials are lithium niobate (LiNbO ₃ ), potassium dihydrogen phosphate (KDP),
Inorganic materials such as gallium arsenide (GaAs) and semiconductor materials have been mainly investigated. However, these materials have many problems in that they have a small nonlinear optical constant, a low threshold value for laser light breakdown, deliquescent, and response speed. In contrast, organic compounds have large nonlinear optical constants,
Since there is a possibility that a material with a fast response speed may be obtained,
In recent years, research and development of organic compound-based nonlinear optical materials have been actively pursued in various fields. As organic nonlinear optical materials, materials having excellent nonlinear optical characteristics such as methylparanitroaniline (MNA) and methylparanitro-N-oxidepyridine (POM) have already been found.

[0004]

The development of organic nonlinear optical materials used for wavelength conversion elements and electro-optical elements is basically
It is said that it is sufficient to design and search for a π-electron conjugated compound having an electron-donating group or an electron-withdrawing group in the molecule, but there are the following problems. First, it is necessary that the molecule and the crystal structure have no center of inversion symmetry. This is a major problem in the search for organic SHG materials, because the prediction of the crystal structure is virtually impossible with the current degree of theoretical calculation. Further, if the compound itself has absorption in the SHG wavelength region, the conversion efficiency of the laser decreases, so it is necessary to shorten the absorption wavelength end. It is relatively easy to shorten the absorption wavelength edge at the stage of molecular design, but it is difficult to develop a material that does not cause a decrease in SHG activity. In order to solve such a problem, a methanediamine benzoic acid-based compound has been developed (JP-A-4-70821). However, a material having a sufficient function as a material for a nonlinear optical element has not been found, and development of an organic nonlinear optical material having higher characteristics is strongly desired.

An object of the present invention is to provide an organic non-linear optical material having large non-linear optical characteristics and excellent transparency, and an optical functional device using the same.

[0006]

In order to achieve the above object, an N-acylamide compound described in the claims was designed and synthesized, its nonlinear optical characteristics were evaluated, and its absorption wavelength was measured. As a result, they have found that the N-acyl amide compound has relatively large non-linear optical characteristics, and at the same time, has excellent transparency, and arrived at the present invention. The gist of the present invention is as follows.

(1) An organic nonlinear optical material comprising a compound represented by Chemical formula 3.

[0008]

[Chemical 3]

[However, at least one of Ar ₁ and Ar ₂ is an atomic group having an optionally substituted π-electron conjugated structure. In the chemical formula 3, at least one of Ar ₁ and Ar ₂ is a hydrocarbon-based aromatic represented by a benzene ring, a naphthalene ring, an anthracene ring, a benzoquinone ring, a naphthoquinone ring, an anthraquinone ring, a pyrrole ring, an imidazole ring, It is a compound represented by a π-conjugated atomic group selected from the group consisting of a heterocycle represented by an indole ring, a quinoline ring, a phenazine ring, or a cinnamyl group.

Further, in Chemical formula 3, Ar ₁ and Ar ₂ are nitro group, cyano group, isocyanate group, carboxy group,
Alkylsulfonyl group, allylsulfonyl group, alkylsulfinyl group, allylsulfinyl group, acylamino group, carbamoyl group, sulfamoyl group, acyloxy group, alkyloxycarbonyl group, allyloxycarbonyl group, alkyl group, allyl group, alkoxy group, allyloxy group, It is a compound substituted with an organic substituent selected from the group consisting of an alkyloxysulfonyl group, an allyloxysulfonyl group, an alkylthio group, an allylthio group, a hydroxy group, a thiol group, and a halogen atom.

(2) An organic nonlinear optical material comprising a compound represented by the chemical formula 4.

[0012]

[Chemical 4]

[However, R ₁ is a substituent, and the benzene ring to which R ₁ is bonded may be substituted with a substituent other than R ₁ . R ₂ is an organic substituent containing at least one carbon atom. In the chemical formula 4, R ₁ is a nitro group, a cyano group, an isocyanate group, a carboxy group, an alkylsulfonyl group,
Allylsulfonyl group, alkylsulfinyl group, allylsulfinyl group, acylamino group, carbamoyl group, sulfamoyl group, acyloxy group, alkyloxycarbonyl group, allyloxycarbonyl group, alkyl group, allyl group, alkoxy group, allyloxy group, alkyloxysulfonyl group , An allyloxysulfonyl group, an alkylthio group, an allylthio group, a hydroxy group, a thiol group, and a halogen atom, which are organic substituents.

(3) It has a light incident surface and a light emitting surface.
Alternatively, it is an optical functional element having the organic nonlinear optical material shown in Chemical formula 4 as a constituent element.

(4) The organic nonlinear optical material described in Chemical formula 3 or 4 is a single crystal of 1 mm square or more, or a film in which the organic nonlinear optical material is dispersed in a transparent polymer and oriented in a strong electric field. And an optical functional element characterized by being held in an optical resonator.

An optical functional element characterized in that the transparent high molecular weight polymer in which the organic nonlinear optical material is dispersed is a polymer having no absorption at 400 nm or more.

As the transparent high molecular polymer in which the organic nonlinear optical material is dispersed, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, styrene, etc. are typical. A transparent high molecular polymer obtained by polymerizing the monomer is used. In particular, the polymer is 40
It is desirable that the polymer has no absorption above 0 nm. The dispersion is oriented under a strong electric field. In addition, the dispersion can be obtained by previously dispersing a non-linear medium in the monomer and polymerizing the non-linear medium while orienting the non-linear material in a strong electric field. It can also be obtained by polymerizing a monomer in which the non-linear material is dispersed, heating the polymer above the glass transition temperature of the polymer, and then gradually cooling it under a strong electric field.

Furthermore, the organic nonlinear optical material described in Chemical formula 3 or Chemical formula 4 may be introduced as a polymer side chain, and the polymeric material is subjected to heat treatment under an electric field in the same manner as in the above method to obtain nonlinear optical characteristics. Can be given.

(5) An optical function characterized in that the single crystal or polymer dispersion of the organic nonlinear optical material described in Chemical formula 3 or Chemical formula 4 has an optical waveguide filled in a space surrounded by a cladding layer. Sex element.

(6) An optical functional element having an optical waveguide formed on a substrate, wherein the optical waveguide is made of a single crystal or polymer dispersion of the organic nonlinear optical material described in Chemical formula 3 or Chemical formula 4. An optical functional element characterized in that

(7) Light having a light source, a condensing means for condensing the light from the light source, and a harmonic generating means for receiving the light condensed by the condensing means to generate a second harmonic. A wavelength conversion device, wherein the second harmonic generation means comprises a single crystal of the organic nonlinear optical material shown in Chemical formula 3 or 4 or a polymer dispersion thereof in an optical path. Wavelength converter.

(8) In the electro-optical element for switching or modulating an optical signal by the electro-optical effect, the electro-optical element is a single crystal of the organic nonlinear optical material shown in Chemical formula 3 or 4 or a polymer dispersion thereof. An electro-optical element having a body in the optical path.

1 to 3 are schematic views of an optical functional device using the compound of the present invention. In FIGS. 1 and 2, 1 indicates a cladding layer and 2 indicates a nonlinear optical material of the present invention. In FIG. 3, 3 is a substrate and 2 is a nonlinear optical material of the present invention.

4 to 6 are explanatory views of an optical wavelength conversion device to which the optical functional element of the present invention is applied. Reference numeral 4 is a semi-transmissive mirror used in the device of the present invention. In the figure, 5 is a light source used for the optical functional element of the present invention. Reference numeral 6 is an optical functional element of the present invention. Reference numeral 7 is a polarizing plate. Reference numerals 8 and 9 denote incident light and emitted light. Reference numeral 10 is a reflecting mirror, 11 is return light, and 12 is other incident light.

FIG. 7 is an explanatory view of a specific example of an optical wavelength conversion device to which the optical functional element of the present invention is applied. A laser beam 18 from a laser diode 13 (GaAlAs semiconductor laser beam; wavelength 0.88 to 0.8) is applied to an SHG element 17 having a core of a single crystal of the organic nonlinear material or a polymer dispersion thereof and a cladding layer surrounding the core. 75 μm) collimator 1
4. The second harmonic of blue light (wavelength 0.44 to 0.37 μm) can be obtained by transmitting the light through the anamorphic prism pair 15 and the condenser lens 16. By using the SHG element 17 of the present invention, an optical wavelength conversion device having a short cutoff wavelength and excellent laser light resistance can be obtained.

FIG. 8 shows an example of a resonator type wavelength conversion device to which the organic nonlinear optical material of the present invention is applied. The excitation light 23 from the laser diode 13 through the lens 19 causes N
The d: YAG rod 20 is excited, and the fundamental wave 21 generated therefrom is converted into the emitted light 9 through the nonlinear optical material 2 of the present invention and the concave mirror 22.

FIG. 9 shows an example of an electro-optical element using the organic nonlinear optical material of the present application. A voltage is applied by an electrode 24 and a modulation power supply 25 to an optical waveguide composed of the nonlinear optical material 2 formed on the substrate 3 to modulate the incident light 8 and obtain the emitted light 9.

Furthermore, the organic nonlinear optical material of the present invention can be applied to second-order nonlinear devices such as optical rectification, optical mixing, and parametric amplifier.

The organic nonlinear optical material of the present invention can be applied to a third-order nonlinear device such as third harmonic generation, Kerr shutter, light mixing, optical memory utilizing optical bistability, and optical operation element.

For the organic nonlinear optical material of the present invention, a single crystal is prepared by a method of precipitating a crystal from an organic solvent, a Bridgman method, a melting method such as Czochralski method, a sublimation method, etc., and cutting and polishing. By doing so, it can be used as a wavelength conversion element. It can also be used as a Cherenkov type or quasi phase matching type non-linear device.

Representative examples of the N-acylamide compound of the present invention are shown in Chemical formulas 5 to 17.

[0032]

[Chemical 5]

[0033]

[Chemical 6]

[0034]

[Chemical 7]

[0035]

[Chemical 8]

[0036]

[Chemical 9]

[0037]

[Chemical 10]

[0038]

[Chemical 11]

[0039]

[Chemical 12]

[0040]

[Chemical 13]

[0041]

[Chemical 14]

[0042]

[Chemical 15]

[0043]

[Chemical 16]

[0044]

[Chemical 17]

Next, a method for synthesizing the N-acylamide derivative will be described. The N-acyl amide derivative is
As shown in Chemical formula 3, it can be synthesized by reacting the corresponding amide compound with an acid chloride in the presence of a base.

[0046]

[Chemical 18]

The organic nonlinear optical material of the present invention can be synthesized by a known synthesis method other than the above.

[0048]

The effect of the molecular structure of the N-acylamide derivative of the present invention on the crystal structure was examined. As a result, it is easy to construct a hydrogen bond between the carbonyl group in the molecular structure and the hydrogen atom of NH as shown in Chemical formula 19, and the molecular structure of the compound of the present invention effectively acts on the construction of a non-centrosymmetric crystal structure. It turned out that

[0049]

[Chemical 19]

Actually, regarding dibenzimide, South African Journal of Chemistry, 36, p137-
142, 1983, for N-isobutylbenzamide, Acta Crystallographica, C41, p26.
It was reported in 3-264,1985 that the structure shown in Chemical formula 19 was obtained for crystal structure analysis of these compounds.

Regarding the nonlinear optical characteristics, various characteristics such as the hyperpolarizability of the molecule alone, the minimum excitation energy and the intermolecular interaction are calculated, and the element characteristics of the optical functional element having the organic nonlinear optical material as the constituent element are calculated by theoretical calculation. Was examined.

As a result, the organic nonlinear optical material of the present invention has a sufficiently short absorption wavelength edge as a material for a wavelength conversion element, and the molecules are easily arranged effectively in the crystal as shown in Chemical formula 19, so that it is high. It was found to have non-linear optical properties.

Further, it has been found that the N-acylamide compound has excellent characteristics in an optical functional device having it as a constituent element.

[0054]

EXAMPLES Next, the present invention will be described with reference to Examples, and its synthetic method,
Detailed explanation including evaluation method.

Example 1 Benzamide (1.22 g) was dissolved in pyridine (6 ml), and benzoyl chloride (1.7 ml) was added thereto. After stirring for about 4 hours, diethyl ether was added and the mixture was washed with water, the organic layer was separated, and the solvent was evaporated to obtain the desired compound dibenzamide (0.4 g,
18%). The results of elemental analysis are C: 74.5%, H: 5.
01%, N; 6.01% (calculated value is C; 74.7%,
H; 4.92%, N; 6.21%).

Example 2 4-Methoxybenzamide
(1.52 g) is dissolved in pyridine (8 ml), and benzoyl chloride (1.7 ml) is added thereto. After stirring for about 8 hours, diethyl ether was added and the mixture was washed with water, the organic layer was separated, and the solvent was evaporated to give the desired compound 4-methoxydibenzamide (1.03 g, 43%). The results of elemental analysis are C: 70.5%, H: 5.21%, N: 5.21%
(Calculated values are C; 70.6%, H; 5.13%, N; 5.
49%).

Example 3 4-Nitrobenzamide (1.
66 g) is dissolved in pyridine (10 ml), and acetyl chloride (0.8 ml) is added thereto. After stirring for about 6 hours, diethyl ether was added and the mixture was washed with water, the organic layer was separated, and the solvent was evaporated to obtain the target compound N-acetyl-4-nitrobenzamide (0.21 g, 10%). The results of elemental analysis are C; 51.8%, H; 3.93%, N; 1
3.2% (calculated values are C; 51.9%, H; 3.87%,
N; 13.5%).

Example 4 Cinnamamide (1.47 g)
Is dissolved in pyridine (10 ml), and cinnamoyl chloride (1.8 g) is added thereto. After stirring for about 5 hours,
After adding diethyl ether and washing with water, the organic layer was separated and the solvent was distilled off to obtain the objective compound dicinnamamide (0.1).
91 g, 33%). The result of elemental analysis is C: 77.9
%, H; 5.60%, N; 4.91% (calculated value: C; 78.
0%, H; 5.45%, N; 5.05%).

Example 5 Benzamide (1.22 g) was dissolved in pyridine (6 ml), and isobutyryl chloride (1.3 ml) was added thereto. After stirring for about 4 hours, diethyl ether was added and the mixture was washed with water, the organic layer was separated, and the solvent was evaporated to obtain the target compound N-isobutyrylbenzamide (0.45 g, 24%). The result of elemental analysis is
C; 69.0%, H; 6.96%, N; 7.25% (calculated values are C; 69.1%, H; 6.85%, N; 7.32
%)Met.

Example 6 Generation of the second harmonic (SHG) of each powder of the compounds obtained in Examples 1 and 5 was observed. The experiment was conducted by SK Kurtz and TT Perry (J.Appl.Phy
s., 39, 3798 (1968)). A Q-switch YAG laser (wavelength 1064 nm) was used as a light source for the measurement. When the powder sample was irradiated with laser light, green light with a wavelength of 532 nm was observed.

Further, when a wavelength conversion element for a laser was manufactured using the single crystal of the compound obtained in Example 1, the wavelength conversion element operated effectively and the second harmonic wave was obtained.

Example 7 Generation of the third harmonic (THG) of the compounds obtained in Examples 1 to 5 was observed. In the experiment, a Q-switch YAG laser (wavelength 1064 nm),
A dye laser (wavelength 681 nm) using the second harmonic (wavelength 532 nm) as an excitation light source is used to
Introducing m and 681 nm light into the difference frequency generator,
When converted to 0 nm infrared light and irradiated on the samples of Examples 1 to 4, THG of 633 nm was observed.

Example 8 A wavelength conversion element was produced using the compound obtained in Example 1. To prepare the wavelength conversion element, the compound was first highly purified by a recrystallization method from a solvent.

Next, when the highly purified compound is kept in a molten state and a hollow glass capillary is introduced into the molten compound from one end, the compound is filled in the hollow portion of the glass capillary by a capillary phenomenon. By slowly drawing this into an atmosphere at a temperature lower than the melting point of the compound, the hollow portion of the glass capillary is filled with the single crystal or polycrystal of the compound.

When the filled compound is in a polycrystalline state, the glass capillary is heated again to the melting point of the compound or higher, and then pulled out to a temperature lower than the melting point to single crystallize the compound.

When laser light was made to enter the wavelength conversion element manufactured as described above, emission of light having a half wavelength of the laser light was confirmed.

Example 9 The dibenzamide obtained in Example 1 was mixed with methyl methacrylate monomer and heat-polymerized. A film prepared by spin-coating a polymer dissolved in chloroform was subjected to corona poling. In the corona poling, the distance between the electrodes was set to 1 cm, and heating was performed at an applied voltage of 7 kV and 110 ° C. for 1 hour, and then the voltage was applied and cooled to room temperature.

When the nonlinear optical element of the wavelength conversion device was formed by using the nonlinear optical material, the second harmonic wave similar to the case of using the single crystal was obtained.

[0069]

The organic nonlinear material of the present invention has excellent nonlinear characteristics, and by using the organic nonlinear optical material, an optical functional element represented by a semiconductor laser wavelength converter, an optical switch, etc. is provided. be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an optical functional element using an organic nonlinear optical material of the present invention.

FIG. 2 is an explanatory diagram of another optical functional element using the organic nonlinear optical material of the present invention.

FIG. 3 is an explanatory diagram of another optical functional element using the organic nonlinear optical material of the present invention.

FIG. 4 is an explanatory diagram of an optical wavelength conversion device to which the optical functional element of the present invention is applied.

FIG. 5 is an explanatory diagram of another optical wavelength conversion device to which the optical functional element of the present invention is applied.

FIG. 6 is an explanatory diagram of another optical wavelength conversion device to which the optical functional element of the present invention is applied.

FIG. 7 is an explanatory diagram of an optical wavelength conversion device to which the nonlinear optical element of the present invention is applied.

FIG. 8 is an explanatory diagram of a resonator type optical wavelength conversion device to which the organic nonlinear optical material of the present invention is applied.

FIG. 9 is a perspective view of an electro-optical element using the organic nonlinear optical material of the present invention.

[Explanation of symbols]

1 ... Clad layer, 2 ... Non-linear optical material, 3 ... Substrate, 4 ...
Semi-transmissive mirror, 5 ... Light source, 6 ... Optical functional element, 7 ... Polarizing plate,
8 ... Incident light, 9 ... Emitted light, 10 ... Reflector, 11 ... Return light, 12 ... Other incident light, 13 ... Laser diode, 14
… Collimator, 15… Anamorphic prism pair,
16 ... Condensing lens, 17 ... SHG element, 18 ... Laser beam, 19 ... Lens, 20 ... Nd: YAG rod, 21 ...
Fundamental wave, 22 ... concave mirror, 23 ... excitation light, 24 ... electrode,
25 ... Modulation power supply.

Claims (11)

[Claims] 1. An organic nonlinear optical material comprising a compound represented by Chemical formula 1. [Chemical 1] [However, at least one of Ar ₁ and Ar ₂ is an optionally substituted atomic group having a π-electron conjugated structure. ] _2. The aromatic aromatic hydrocarbon represented by a benzene ring, a naphthalene ring, an anthracene ring or the like, a benzoquinone ring, and at least one of Ar ₁ and Ar _{2 according to} claim 1.
An organic nonlinear optical material that is a heterocyclic ring represented by a naphthoquinone ring, an anthraquinone ring, a pyrrole ring, an imidazole ring, an indole ring, a quinoline ring, a phenazine ring, or a π-conjugated atomic group selected from the group consisting of cinnamyl groups. 3. The Ar ₁ and Ar _{2 according to} claim 1 or 2.
At least one of nitro group, cyano group, isocyanate group, carboxy group, alkylsulfonyl group, allylsulfonyl group, alkylsulfinyl group, allylsulfinyl group, acylamino group, carbamoyl group, sulfamoyl group, acyloxy group, alkyloxycarbonyl group, allyl Organic substitution selected from the group consisting of oxycarbonyl group, alkyl group, allyl group, alkoxy group, allyloxy group, alkyloxysulfonyl group, allyloxysulfonyl group, alkylthio group, allylthio group, hydroxy group, thiol group, and halogen atom. Organic nonlinear optical material substituted by groups. 4. An organic nonlinear optical material comprising a compound represented by Chemical formula 2. [Chemical 2] [However, R ₁ is a substituent, and the benzene ring to which R ₁ is bonded may be substituted with a substituent other than R ₁ . R ₂ is an organic substituent containing at least one carbon atom. ] 5. The method of claim 4, R ₁ is a nitro group, a cyano group, an isocyanate group, a carboxy group, an alkylsulfonyl group, an allyl sulfonyl group, an alkylsulfinyl group, an allyl sulfinyl group, an acylamino group, a carbamoyl group, a sulfamoyl group, Acyloxy group, alkyloxycarbonyl group, allyloxycarbonyl group, alkyl group, allyl group, alkoxy group, allyloxy group, alkyloxysulfonyl group, allyloxysulfonyl group, alkylthio group, allylthio group, hydroxy group, thiol group, halogen atom An organic nonlinear optical material which is an organic substituent selected from the group consisting of: 6. The method according to claim 1, 2, 3, 4 or 5.
An optical functional element having an incident surface and an emission surface for light and having an organic nonlinear optical material as a constituent element. 7. The method according to claim 1, 2, 3, 4 or 5,
The organic nonlinear optical material comprises a single crystal of 1 mm square or more, or a film in which the organic nonlinear optical material is dispersed in a transparent high molecular polymer and oriented in a strong electric field, which is held in an optical resonator. Non-linear optical element. 8. The nonlinear optical element according to claim 7, wherein the transparent high molecular weight polymer in which the organic nonlinear optical material is dispersed is a polymer having no absorption at 400 nm or more. 9. The method according to claim 1, 2, 3, 4 or 5.
An organic nonlinear optical element having an optical waveguide in which a single crystal or polymer dispersion of the organic nonlinear optical material is filled in a space to be a core surrounded by a cladding layer. 10. The light source according to claim 1, 2, 3, 4 or 5, and a light condensing means for condensing light from the light source.
An optical wavelength conversion device having a harmonic generation unit that receives the light condensed by the condensing unit and generates a second harmonic, wherein the second harmonic generation unit is a unit of the organic nonlinear optical material. An optical wavelength conversion device comprising a crystal or a polymer dispersion thereof in the optical path. 11. The single crystal of the organic nonlinear optical material or a polymer dispersion thereof according to claim 1, 2, 3, 4, or 5, wherein the electro-optical element for switching or modulating an optical signal by an electro-optical effect is a single crystal of the organic nonlinear optical material. An electro-optical element provided with in the optical path.