JPH03167532A - New organic nonlinear optical material and method for converting wavelength of light with same - Google Patents

Abstract

PURPOSE:To obtain an optical material having high nonlinear responsiveness and superior blue light transmittance by using a specified compd. CONSTITUTION:A quinoline-N-oxide deriv. represented by formula I is used as an org. nonlinear optical responsive compd. In the formula I, one of R1-R7 is a pi-electron donative group such as arylthio or alkylthio and each of the remaining substituents is H or 1-18C alkyl. An optical material having high nonlinear responsiveness and superior blue light transmittance is obtd.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a nonlinear optical material suitable for use in various devices that utilize nonlinear optical effects, such as wavelength conversion devices. It also relates to a method of converting optical wavelength using nonlinear optical materials. (Prior art) In recent years, materials with nonlinear optical effects, which exhibit nonlinearity between polarization and electric field when a strong optical electric field such as that of a laser beam is applied, have attracted attention. Such materials are generally known as nonlinear optical materials and are described in detail in, for example: 'Nonlinear Optical Properties of Organic Polymeric Materials (Nonlin
er Optical Properties of O
rganic and Polymerie Mate
real)' Koichi C.S. Symposium
Series (ACS SYMPOSIUMSEI?rES
) 2 3 3, David Jay Williams (D
avid J. Williams) m American Chemical Society
ety. ．． 1983), ``Organic Nonlinear Optical Materials'', supervised by Masao Kato and Hachiro Nakanishi (CMC, published 1985), 'Nonlinear Optical Properties of Organic Molecules.
and Crystals (Nonljner Optic
al Properties of OrganicM
olecules and crstals)' Volumes 1 and 2 2), D.S. Shemra and J.J.
emla and J. Academic Press, 198
Published in 7 years.

One of the applications of nonlinear optical materials is second harmonic generation (SHG) based on second-order nonlinear effects and wavelength conversion devices using sum and difference frequencies. The ones that have been used in practice so far are inorganic velourites, represented by lithium niobate. However, in recent years, it has become known that π-electron conjugated organic compounds with electron-donating and electron-withdrawing groups have various properties as nonlinear optical materials that far exceed those of the inorganic materials mentioned above. Therefore, as an organic compound exhibiting a nonlinear optical response to be used in this material, it is desirable to have a high nonlinear susceptibility in the molecular state. It is known that compounds with long π-electron conjugated chains are useful for exhibiting such properties, and are variously described in the above-mentioned literature. As the wavelength becomes longer, for example, the transmittance of blue light decreases, and this becomes an obstacle to the generation of blue light as the second harmonic. This also occurs in P-nitroaniline derivatives, and the fact that the efficiency of second harmonic generation is greatly influenced by the transmittance of that wavelength is evidenced by the fact that Align
Alain llt4ma et al., Proceedings of SBI
edings of SPIE), Volume 400, New
Optical Materials (Now Optial)
Materials), (1983), p. 186, Figure 4. Therefore, the emergence of nonlinear optical materials with high transmittance for blue light is desired. Previous attempts have been made to replace the carbon atoms in the benzene nucleus of nitroaniline with nitrogen atoms, but satisfactory results have not always been obtained. (Problems to be Solved by the Invention) Therefore, the first object of the present invention is to provide an organic nonlinear optical material that exhibits high nonlinear responsiveness and has excellent blue light transmittance. The second purpose is to provide a method that utilizes the response during optical wavelength conversion among nonlinear responses.

(Means for Solving the Problems) As a result of extensive research, the present inventors have found the following general formula (1
It has been found that the objects of the present invention can be achieved by using a quinoline-N-oxide derivative represented by ) as an organic nonlinear optically responsive compound. General formula (1) 0 (wherein, one of R to R represents a π-electron donating group. The remaining substituents are hydrogen atoms or have 1-1 carbon atoms.
8 represents an alkyl group. Here, the π electron donating group is σG
<-2.0 means a substituent. ) Substituent constant σ mentioned above
[is "Kagakusen ξner" Vol. 10, pages 61-63, Naoki Inamoto, published by Maruzen Co., Ltd. "Structure and Reactivity -" by Noriyuki Yanot
represents the value described in , and as a π electron donating group, σ<<
2.0 means a substituent. For example, arylthio group, alkylthio group, biridylthio group, aryloxy group, alkoxy group, pyridoxy group, aryloxy group, alkylamino group, arylalkyl ξ group, pyridylamino group, dipyridylago group, molyphoryl group, piveridyl group, Examples include halogen atoms. Examples of the arylthio group include phenylthio group and naphthylthio group, with 2-naphthylthio group being particularly preferred. In addition, alkylthio groups have an alkyl chain having 1 to 18 carbon atoms, such as methylthio group, ethylthio group,
Examples include propylthio group, cyclohexylthio group, octadecylthio group, benzylthio group, and 2-phenylethylthio group. Examples of the aryloxy group include phenoxy group, naphthoxy group, 4-chlorophenoxy group, 4-methylphenoxy group, 4-methoxyphenoxy group, and 2-methyl-l-naphthoxy group. The alkoxy group has an alkyl chain having 1 to 22 carbon atoms, such as methoxy group, ethoxy group, probyloxy group, cyclohexyloxy group, octadecyloxy group, penzyloxy group, 2-phenylethoxy group, 2-chloro Examples include ethoxy group, with methoxy group being particularly preferred. Examples of the arylamino group include phenylamino group, diphenylamino group, naphthylamino group, 4-chlorophenylamino group, 4-methylphenylamino group, 4-methoxyphenylamino group, and 4-chloronaphthylamino group. Examples of the alkyla ξ group include those having an alkyl group having 1 to 18 carbon atoms, such as a methylamino group, a dimethyl ξ group, an ethylamino group, a diethylamino group, a propylamino group, a cyclohexylamino group, and an octadecylamino group. , benzylamino group, 2-phenylethylamino group, 2-chloroethylamino group, etc. Examples of the aryl alkylamino group include N-phenyl-N-methylamino group, N-phenyl-N-ethylamino group, N-
Examples include (41 lorophenyl)-N-methylamino group. Examples of the halogen atom include a fluoro group, a chloro group, and a bro-7 group. The substitution position of these substituents is preferably the 2-position or the 6-position.

The remaining alkyl group as a substituent has 1 to 1 carbon atoms.
18 alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group. Specific examples of the compound (1) used in the present invention are shown below, but the scope of the present invention is not limited thereto. These compounds are described in "Pharmaceutical Journal" Vol. 86, 749-7.
It can be synthesized according to the method described in the synthesis section of ``Research on tertiary amine oxides'' by Kizen Yamazaki, Noriko Honjo, Hiroharu Noda, Yayoi Nagano, and Masakazu Hamana, page 55. In addition, the efficacy of compound 12 was published in the Journal of Perma-Soybean Society of Japan (J.Ph.
avm. Soc. Japan), Volume 64 (vol.6
4) N [L8A, pp. 72-73, Eiji Ochiai Masao Ishikawa and Asai Zairen (Eij
iOchiai, Masao lshikawaa
Syntheses of Aromatic Tertiary Amine-N-Oxides
aromatic tevtiary ami
neN-oxudes). As will be clear from the Examples described below, the nonlinear optical material of the present invention is particularly useful as a material for converting the optical wavelength of laser light. However, the application of the nonlinear optical material of the present invention is not limited to wavelength conversion elements, but can be used for any element that utilizes nonlinear optical effects.

Specific examples of devices in which the nonlinear optical material of the present invention can be used include, in addition to wavelength conversion devices, optical bistable devices (optical storage devices, optical pulse waveform control devices, optical limiters, differential amplification devices,
Examples include optical transistors, A/D conversion elements, optical logic elements, optical multivibrator optical flimb-flop circuits, etc.), optical modulation elements, and phase conjugate optical elements.

The compounds of the invention may be present, for example, in the form of a powder, in the form of molecular inclusions in a host lattice (bolimers, clathrates, solid solutions, liquid crystals), in the form of thin layers deposited on a support (rangs ξ-a, It can be used as a nonlinear optical material in various forms, such as a projector film, etc.), a single crystal, and a solution.

Furthermore, the compound of the present invention can also be used in the form of a pendant, bonded to volima, boridiacetylene, etc. For details on these methods, see D. above. J. Will
It is described in the works edited by Iass. (Example) Next, the present invention will be described in detail based on an example.

Example 1 Measurement of second harmonic generation was carried out by S.K.
Kurtz), T.T.Perry (T.T.Pe)
(J.Appl.Phys.) 3 9 3798
According to the method described in page (published in 1968),
This test was carried out on powder of the compound of the present invention.

Measurements were carried out using the apparatus shown in FIG.

That is, the measurement is performed using pulsed YAG laser light (λ"1.
064μm, beam diameter! : i l mlφ, peak power ζ 10 Mw/c+i) was used as the fundamental wave, and the intensity of its second harmonic was measured using the evaluation device shown in FIG. The measurement was performed by relative comparison with the intensity of the second harmonic of urea. In particular, in order to distinguish between the light emission (mainly yellow and red light emission) caused by two-photon absorption of the fundamental wave and the second harmonic, a spectrometer is installed.
I made it possible to measure only the second harmonic. Furthermore, the main purpose of powder method measurement is to determine the presence or absence of nonlinearity in the substance, and the intensity ratio is a reference value for the magnitude of nonlinearity.

The results are shown in Table 1 using MNA, which is well known as a nonlinear optical material, as a comparative example.

Table 1 1) Wavelengths showing 95% transmittance in ethanol solution of 4 x 10-'mol/l.

Table 1 shows that this compound is at λ cut off, has a shorter wavelength than MNA, and has excellent blue light transmittance.

(Effects of the Invention) Compounds that exhibit SHG activity using these rice powder methods can be used as wavelength conversion elements by the method described below.

1. It is possible to single-crystallize the above compound in the core of the fiber, create a wavelength conversion element using glass as the cladding material, input YAG laser light, and generate its second harmonic. Furthermore, as another method, it is possible to similarly generate a second harmonic by using a waveguide type wavelength conversion element. The Cerenkov radiation method was used as the phase matching method at this time. However, the present invention is not limited to these, and phase matching between waveguides is also possible. Wavelength converted waves are not only limited to second harmonics, but can also be used to generate third harmonics, sum and difference frequencies. 2. Next, the above compound was single crystallized, a Hulk single crystal was cut out from it, and Y
It is possible to manually generate the second harmonic of AG laser light. Angular phase matching was used as the phase matching method at this time. These bulk single crystals can be used not only outside the laser cavity, but also within the cavity of a solid-state laser such as an LD-pumped solid-state laser to improve wavelength conversion efficiency. Furthermore, the wavelength conversion efficiency can also be increased by placing it inside an external resonator type LD resonator.

The Bringeman method, solvent evaporation method, etc. are used for the above single crystallization.

Wavelength converted waves are not only limited to second harmonics, but can also be used to generate third harmonics and sum-difference frequencies.

[Brief explanation of the drawing]

Figure 1 shows a powder method measuring device, and the numbers in the figure indicate the following.

Claims (1)

[Claims] (1) An organic nonlinear optical material comprising a compound represented by the following general formula (I). General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, one of R_1 to R_7 represents a π electron donating group. The remaining substituents are hydrogen atoms or alkyl groups having 1 to 18 carbon atoms. Here, the π electron donating group is σ^P_
It means a substituent in which R<-2.0. )(2) When converting the optical wavelength using a laser beam and a nonlinear optical material,
A method of converting light wavelength using the organic nonlinear optical material according to claim 1 as a nonlinear optical material.