JP2636062B2 - Method for producing film-like nonlinear optical material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a nonlinear optical material, and more particularly, to a film having high nonlinear optical properties in which a polydiacetylene crystal is dispersed in a synthetic resin film. The present invention relates to a novel method for producing a sheet-like material.

2. Description of the Related Art Among polarizations induced in a substance when light passes through the substance, an amount proportional to the square of the electric field intensity of the light or more is called non-linear polarization. Generally, in the case of ordinary light where the electric field of light is small,
Only the linear effect is observed, but under coherent strong electric field light such as laser light, nonlinear polarization increases,
As a result, a nonlinear optical effect appears. The second-order nonlinear optical effects include second harmonic generation (SHG), parametric oscillation, and Pockels effect. The third-order nonlinear optical effects include third harmonic generation (THG), electric-field-induced SHG, and the Kerr effect. , Optical phase conjugation, optical bistability, and the like. Non-linear optical materials that efficiently express these effects are elements that support the backbone of new optoelectronics.
It is attracting attention as an indispensable material for realizing an optical computer, such as a light modulation element for laser wavelength conversion, a high-speed switching element, an optical theory gate, and an optical transistor.

Currently, nonlinear optical materials include potassium dihydrogen phosphate (KDP), lithium niobate, and bismuth silicate (BS
O), inorganic materials such as gallium-arsenide superlattice semiconductors, urea, 2-methyl-4-nitroaniline (MN
A) Organic materials such as 2-acetylamido-4-nitro-N, N-dimethylaniline (DAN), 4-diethylamino-4'-nitrostilbene (DEANS), cyanine dye, polyacetylene, polydiacetylene, phthalocyanine, Research and development for practical use or practical use are underway.

IEEE Spectrum Ju
ne (1981), pp. 26-33, generally, organic materials have a larger nonlinear optical effect than inorganic crystals, and SHG
And the coefficient such as THG is about 10 to 1000 times, and the light response speed is 1000 times or more. It has also been recognized that the threshold value for optical damage is large.

The excellent properties of such organic nonlinear optical materials are described in more detail in the following literature.

`` Nonlinear Optical Properties of Organic M
olecules and Crystals '' DSC Chemla and J. Zyss
Eds. (ACADEMIC PRESS, Inc., 1987) "Organic Nonlinear Optical Materials", edited by Masao Kato and Hachiro Nakanishi (CMC Publishing Co., Ltd., 1985) Problems to be solved by the invention. As for the performance, it is a matter of course that the highest non-linear optical property is the highest priority, but the optical uniformity, transparency, and ease of processing including thinning are also important.

Among organic and polymer materials with large nonlinear optical properties, polydiacetylene is obtained as a polymer crystal in which the conjugate main chain is completely oriented by a specific reaction called solid-state polymerization, and has a tertiary nonlinearity of 10 ^-9 esu or more. Since optical constants and fast response times of 1 picosecond or less have been reported, the material is expected to be applied to optical switches and optical arithmetic devices utilizing optical bistability. However, since it is a perfectly oriented polymer crystal, most of the derivatives have a disadvantage that they are insoluble in a solvent, and it is not easy to form a thin film despite being a polymer. A thin film formed by vacuum deposition of a diacetylene monomer is irradiated with ultraviolet rays or γ-rays to solid-phase polymerize it into a polydiacetylene thin film. It is difficult to perform vacuum deposition. Also, a method of casting a diacetylene monomer solution or melt on a substrate to form a monomer polycrystalline thin film has poor film surface smoothness and is unsuitable as an optical material.

At present, it is the most demanded to improve the processability of polydiacetylene having a large nonlinear optical characteristic and to facilitate the device formation such as thinning.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a method for easily manufacturing a film-like nonlinear optical material which has been difficult to obtain.

Means for Solving the Problems The present inventors have conducted intensive research on a method of forming a polydiacetylene compound into a film without deteriorating the large nonlinear optical characteristics of the polydiacetylene compound. After mixing a diacetylene compound which is a monomer and forming the film, it has been found that the object can be achieved by forming a polydiacetylene compound by solid-phase polymerization of the diacetylene compound in a synthetic resin film. The present invention has been made based on the findings.

That is, the present invention, in a solvent, a synthetic resin and a solid-state polymerizable diacetylene compound, a volume ratio of 5: 1 to 1:20.
After dissolving at a ratio of, and forming a film by spreading this on a plane and removing the solvent, the diacetylene compound is subjected to solid-phase polymerization to form polydiacetylene dispersed in the synthetic resin film. And a method for producing a film-like nonlinear optical material characterized by the following.

As the synthetic resin used in the present invention, any resin may be used as long as it is soluble in a diacetylene compound and a common solvent.
For example, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polyvinyl carbazole, polymethyl methacrylate, polyisobutyl methacrylate, polyvinyl acetate, polycarbonate, polysulfone, polyacrylonitrile, polyvinyl alcohol, polyethylene oxide, polyacrylic acid, cyanomethyl cellulose , Polyester, polyamide and the like, but are not limited thereto. These may be used alone or in combination of two or more.

Examples of the solid-state polymerizable diacetylene compound used in the present invention include hexadiynediol-p-toluenesulfonate (PTS), dicarbazolylhexadiyne (DCHD), and 5,7-dodecadinin-1,12. -Diol phenyl urethane (TCDU), hexadiyne diol (HDD
O), bis (m-acetylaminophenyl) butadiyne (m-AAPB), bis (4-n-butyltetrafluorophenyl) butadiyne (BTFP), 2,2 ', 5,5'-tetrakis (trifluoromethyl) Diphenyl diacetylene (DF
MP), 3-methylaminophenyl-3,5bis- (trifluoromethyl) phenylbutadiyne (MADF), 1- (3,
5-bis (trifluoromethyl) phenyl) -5-carbazolylpenta-1,3-diyne (DFCP), 4,6-decadiin-1,10-diol bis [(n-butylcarbonylmethyl) urethane] (3BCMU ), 10,12-pentacosadiinoic acid (12-8ADA) and the like, but are not limited thereto. These may be used alone or in combination of two or more.

The mixing ratio of the synthetic resin and the diacetylene compound according to the present invention, the presence or absence of solid-state polymerization of the diacetylene compound,
Film forming properties, optical transparency, limited by the size of nonlinear optical properties, etc., the ratio of the former to the latter on a volume basis is 5: 1 to 1: 2
A range of 0 is preferred. The diacetylene compound contained in the synthetic resin film is solid-phase polymerized by a method such as heating, ultraviolet irradiation, γ-ray irradiation, or the like, thereby obtaining a material having high nonlinear optical characteristics.

The nonlinear optical material of the present invention has a third-order nonlinear optical constant of 10% depending on the content of the polydiacetylene compound.
It can be controlled in the range of ^-12 to 10 ^-8 esu. In addition, since polydiacetylene crystals are dispersed in the resin film with a size of submicron or less, good optical transparency is obtained in the visible to infrared region, and a thin film with excellent optical surface smoothness is produced. Is an easy material.

According to the method of the present invention, the nonlinear optical material is dissolved in a solvent after adding a synthetic resin and a diacetylene compound capable of solid phase polymerization in a volume ratio of 5: 1 to 1:20. It can be manufactured by spreading this on a flat surface to form a film, and then subjecting the diacetylene compound to solid-phase polymerization.

As a solvent used at this time, methyl alcohol, ethyl alcohol, butyl alcohol, acetone,
Methyl ethyl ketone, cyclohexanone, anisole,
Organic solvents such as tetrahydrofuran, dimethylformamide, N-methylpyrrolidone, acetonitrile, ethyl acetate, butyl acetate, chloroform, methylene chloride, diethyl ether, dimethyl cellosolve, benzene, hexane, and cyclohexane, and water, etc. Any solvent may be used as long as it can dissolve both the resin and the diacetylene compound, and the solvent is not limited thereto. These may be used alone or in combination of two or more.

In order to suitably carry out the present invention, first, a synthetic resin and a diacetylene compound capable of solid phase polymerization are uniformly dissolved in the above-mentioned solvent. At this time, the ratio of the former to the latter is 5: 1 on a volume basis
Or 1:20, the concentration of the whole substance is 10-0.01% by weight
A degree is desirable. Casting, immersion, spin coating and the like can be mentioned as a method for casting this solution on a flat surface to form a thin film. Further, when the solvent is hardly distilled off, the film is dried by heating or vacuum drying to form a thin film. In these film forming processes, the addition of the third component as a solute for the purpose of improving film forming properties and dispersibility of diacetylene crystals, functional strength of the obtained film, and the like is not limited at all. . Further, the thickness of the thin film can be easily controlled in a range of about several tens of μm to about 0.01 μm, but is not necessarily limited to this range.

Thus, an almost colorless and transparent thin film in which the diacetylene compound microcrystals capable of solid phase polymerization are uniformly dispersed in the synthetic resin can be obtained. That is, in this thin film, each diacetylene compound forms a unique crystal domain, and therefore, the solid-state polymerizability of the diacetylene compound is preserved, so that they can be polymerized and, at the same time, their fine particles are formed. Since the size of the crystal domain is sufficiently small, scattering loss of light can be reduced.

As a method of solid phase polymerization, heating the obtained thin film,
Alternatively, methods such as ultraviolet irradiation and γ-ray irradiation may be mentioned, and these methods may be used alone or in combination of two or more. In the course of polymerization, these thin films show colors unique to diacetylene compounds such as red, blue and purple, and ultimately,
It is recognized that the surface reflected light became metallic luster and a conjugated main chain of polydiacetylene was formed. The time required for this solid phase polymerization does not differ greatly in the case of a crystal of a diacetylene compound alone, several hours to several days for heating at about 50 to 100 ° C., several minutes to several hours for ultraviolet irradiation, γ-ray irradiation The polymerization is completed in several MRads to several hundred MRads.

A thin film in which polydiacetylene microcrystals are dispersed in the synthetic resin thus obtained has a third-order nonlinear optical constant in the range of 10 ^-12 to 10 ^-8 esu. It was determined from the efficiency of third harmonic generation when irradiated.

EXAMPLES Next, the present invention will be described in more detail with reference to examples.

Example 1 1.2 g of polymethyl methacrylate (PMMA) and 1.4 g of hexadiynediol-p-toluenesulfonate (PTS) are uniformly dissolved in 30 ml of tetrahydrofuran. This solution
1 ml was spread on a 76 × 26 mm glass substrate, and a 0.5 μm thick colorless transparent thin film was formed by spin coating.

When this thin film sample was heated at 60 ° C. for 48 hours, the PTS was solid-state polymerized and turned red, and the reflected light became gold.

The PMMA thus obtained and the po dispersed in it
The nonlinear optical material composed of ly-PTS microcrystals has almost no light scattering in the visible to infrared region, and has an excitation laser wavelength of 2.1
Measurement of the third harmonic generation with respect to μm confirmed that the third-order nonlinear optical constant had 5 × 10 ⁻¹¹ esu.

Example 2 100 mg of polyvinylpyrrolidone (PVPo) and 30 mg of PTS are dissolved in 50 ml of acetone. 3 ml of this solution was spread on a 3x10 mm synthetic quartz substrate and spin-coated to a thickness of 0.1 μm.
Was formed.

When this thin film sample was heated at 60 ° C. for 48 hours, the PTS was solid-state polymerized and turned red, and the reflected light became gold.

The PVPo thus obtained and the po dispersed in it
The nonlinear optical material composed of ly-PTS microcrystals has almost no light scattering in the visible to infrared region, and the excitation laser wavelength is 1.8
Measurement of the third harmonic generation for μm confirmed that it had 1 × ^{10 −10} esu as the third-order nonlinear optical constant.

Example 3 PMMA 120 mg and dicarbazolyl hexadiyne (DCHD) 2.8
g is uniformly dissolved in 100 ml of tetrahydrofuran. 0.1 ml of this solution was spread on a synthetic quartz substrate of 30 × 10 mm, and a colorless transparent thin film having a thickness of 0.05 μm was formed by a spin coating method.

After vacuum drying this thin film sample for 24 hours, γ-ray
Upon irradiation, DCHD was solid-state polymerized and turned blue, and the reflected light showed metallic luster.

The PMMA thus obtained and the po dispersed in it
ly-DCHD nonlinear optical material consisting of crystallites little light scattering in the infrared region from the visible, the third excitation from the measurement of harmonic generation laser wavelength 2.1μm in 1x10 ^-9 esu, further excitation laser at a wavelength of 2 [mu] m 5x10 It was found to have a third order nonlinear optical constant of ^-9 esu.

Example 4 120 mg of PMMA and 140 mg of DCHD are uniformly dissolved in 20 ml of dimethylformamide. 0.3 ml of this solution was spread on a 30 × 10 mm synthetic quartz substrate, and a 0.1 μm thick colorless transparent thin film was formed by spin coating.

After heating and vacuum drying this thin film sample at 50 ° C for 24 hours, 1W
When irradiated with UV light from a low-pressure mercury lamp for 10 minutes and further heated at 70 ° C for 72 hours, DCHD was solid-state polymerized and turned blue.

The PMMA thus obtained and the po dispersed in it
The nonlinear optical material composed of ly-DCHD microcrystal has almost no light scattering in the visible to infrared region, and 3x10 ^-10 esu at the excitation laser wavelength of 2.1 μm and 8 × ¹⁰ esu at the excitation laser wavelength of 2 μm from the measurement of the third harmonic generation. It was found to have a third order nonlinear optical constant of ^-10 esu.

Example 5 100 mg of polystyrene (PSt) and 300 mg of bis (4-n-butyltetrafluorophenyl) butadiyne (BTFP) are uniformly dissolved in 20 ml of benzene. 0.3ml of this solution 30x10mm
And a 0.15 μm thick colorless transparent thin film was formed by spin coating.

By irradiating this thin film sample with UV light from a 1 W low-pressure mercury lamp for 10 minutes, the BTFP was solid-state polymerized and turned blue-violet.

The PSt obtained in this way and the pol dispersed in it
The nonlinear optical material composed of y-BTFP microcrystals has almost no light scattering in the visible to infrared region. From the measurement of the third harmonic generation, 5x10 ^-10 esu at the excitation laser wavelength of 2.1 μm and further at the excitation laser wavelength of 1.8 μm It was found to have a third-order nonlinear optical constant of 5 × 10 ⁻⁹ esu.

Example 6 120 mg of polycarbonate (PC) and 800 mg of 1- (3,5-bis (trifluoromethyl) phenyl) -5-carbazolylpenta-1,3-diyne (DFCP) were mixed with chloroform and methylene chloride at a ratio of 1: 1. Dissolve uniformly in 40 ml of the mixed solvent. A 76 × 26 mm glass substrate was immersed in this solution to form a 0.6 μm thick colorless transparent thin film.

By irradiating this thin film sample with UV light from a 1 W low-pressure mercury lamp for 10 minutes, DFCP was solid-state polymerized and turned blue, and the reflected light turned silver.

The PC obtained in this way and the poly decomposed into it
-Non-linear optical material composed of DFCP microcrystals has almost no light scattering in the visible to infrared region, and has a third-order nonlinear optical constant of 1x10 ^-10 esu at an excitation laser wavelength of 2.1 μm from measurement of third harmonic generation. It was recognized that.

Example 7 1.2 g of polyvinyl carbazole (PVCz) and 2.8 g of 4,6-decadiyne-1,10-diolbis-[(n-butylcarbonylmethyl) urethane] (3BCMU) are uniformly dissolved in 50 ml of tetrahydrofuran. 0.1 ml of this solution was spread on a synthetic quartz substrate of 30x10 mm, and the thickness was 1.
An 8 μm colorless transparent thin film was formed.

After vacuum drying this thin film sample for 24 hours, γ-ray
Upon irradiation, 3BCMU solid-state polymerized and turned red.

The PVCz thus obtained and the po dispersed in it
The nonlinear optical material composed of ly-3BCMU microcrystals has almost no light scattering in the infrared region, and has a third-order nonlinear optical constant of 1 × 10 ^-12 esu at the excitation laser wavelength of 2.1 μm from the measurement of the third harmonic generation. Was observed.

Example 8 200 mg of polyvinyl alcohol (PVA), 300 mg of 10,12-pentacosadinoic acid (12-8ADA), and 100 mg of hexadiynediol (HDDO) were added to a 50% aqueous 0.1% NaOH aqueous solution.
Dissolve uniformly in Spread 0.1 ml of this solution on a 30 x 10 mm synthetic quartz substrate and spin coat it to a thickness of 0.2 μm.
Was formed.

After the thin film sample was vacuum-dried for 24 hours, it was irradiated with UV light from a 1 W high-pressure mercury lamp for 20 minutes, and further heated at 50 ° C. for 48 hours, and the solid phase polymerization of 12-8ADA and HDDO turned reddish brown.

The PVA obtained in this way and the pol dispersed in it
The nonlinear optical material composed of y-12-8ADA and poly-HDDO microcrystals has almost no light scattering in the infrared region. From the measurement of the third harmonic generation, 2 × 10 ^-12 es at a pump laser wavelength of 2.1 μm was measured.
u, and 1x10 ^-11 esu 3 at the excitation laser wavelength of 1.6 μm
It was found to have the following nonlinear optical constants:

Effects The nonlinear optical material and the method for producing the same according to the present invention have large nonlinear optical characteristics, and are excellent in optical uniformity, transparency, workability including thinning, and further, stability over time. It provides a novel material, and is suitable as a material for light modulation elements such as laser wavelength conversion utilizing the third-order nonlinear optical effect, high-speed switching elements, optical theory gates, optical transistors, spatial information elements, etc. .

Continued on the front page (72) Inventor Shigeru Horai 4-1-2, Funariminami, Naka-ku, Hiroshima-shi, Hiroshima Toda Kogyo Co., Ltd.

Claims (1)

(57) [Claims] 1. A synthetic resin and a diacetylene compound capable of solid phase polymerization are dissolved in a solvent at a volume ratio of 5: 1 to 1:20, and the solution is spread on a flat surface to remove the solvent. And then subjecting the diacetylene compound to solid-phase polymerization to form polydiacetylene dispersed in the synthetic resin film.