JP2694562B2 - Novel organic nonlinear optical material and method of converting light wavelength using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a nonlinear optical material suitable for use in various devices utilizing a nonlinear optical effect such as a wavelength conversion device. Further, the present invention relates to a method for converting a light wavelength using a nonlinear optical material.

(Prior Art) In recent years, a material having a nonlinear optical effect-nonlinearity between polarization and an electric field, which appears when a strong optical electric field such as laser light is applied-has attracted attention.

Such materials are generally known as non-linear optical materials and are described in detail, for example, in:
“Nonliner Optical Properties of Organic and Polym
eric Material "ACS SYMPOSIUM SERIES 233 David J. Wil
liams (American Chemical Society, 1983),
"Organic Nonlinear Optical Materials", edited by Masao Kato and Hachiro Nakanishi (CMC, 1985).

One of the applications of the nonlinear optical material is a second harmonic generation (SHG) based on a second-order nonlinear effect and a wavelength conversion device using a sum frequency and a difference frequency. Until now, inorganic perovskites represented by lithium niobate have been practically used. However, in recent years, it has become known that a π-electron child-role organic compound having an electron-donating group and an electron-withdrawing group has various performances as a non-linear optical material which greatly exceeds the above-mentioned inorganic substances.

Therefore, as an organic compound exhibiting a nonlinear optical response to be used for this material, a compound having a high nonlinear susceptibility in a molecular state is desirable. It is known that a compound having a long π-electron conjugated chain is useful for the expression of such properties, and various compounds are described in the above-mentioned literatures. The wavelength becomes longer, for example, the transmittance of blue light is lowered, which hinders the generation of blue light as the second harmonic. This also occurs in the p-nitroaniline derivative, and the fact that the transmittance of the wavelength has a great influence on the efficiency of the second harmonic generation is due to Alain Azem.
a et al., Peoceedings of SPIE, Volume 400, New Optical Mat
erials, (1983) p. 186 FIG.

Therefore, the emergence of a nonlinear optical material having a high transmittance for blue light is desired. Conventionally, it has been studied to replace the carbon atom of the benzene nucleus of nitroaniline with a nitrogen atom or the like, but a satisfactory result has not always been obtained.

(Problems to be Solved by the Invention) Therefore, a first object of the present invention is to provide an organic nonlinear optical material exhibiting high nonlinear response and excellent blue light transmittance. A second object is to provide a method that utilizes the response related to light wavelength conversion among the nonlinear responses.

(Means for Solving the Problems) (1) A nonlinear optical material comprising a compound represented by the following general formula (I).

General formula (I) (Wherein, R represents a hydrogen atom or,, -NO _2, -CN, -C
OR ¹ , -SO ₂ R ¹ , -SOR ¹ , -CF ₃ , -CCl ₃ , -COOR ¹ and a halogen atom (wherein R ¹ is a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group). Group or an aryloxy group is shown). A represents an electron-withdrawing group. D represents an electron donating group. (2) A non-linear optical material comprising a compound represented by the following general formula (I).

General formula (I) (In the formula, R represents a hydrogen atom or an electron-withdrawing group. A represents —NO ₂ , —CN, —COR ¹ , —SO ₂ R ¹ , —SOR ¹ , —
CF ₃ , -CCl ₃ , -COOR ¹ and a halogen atom (where R ¹
Represents a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group or an aryloxy group. Represents an electron-withdrawing group. D represents an electron donating group. (3) A non-linear optical material comprising a compound represented by the following general formula (I).

General formula (I) (In the formula, R represents a hydrogen atom or an electron-withdrawing group. A represents an electron-withdrawing group. D represents R ¹ , -NH ₂ , -N.
HCOCH ₃ , -N (R ² ) ₂ , An electron-donating group selected from --NHNH ₂ and --OR ² (where
R ¹ is the same as R ¹ according to claim (1) or (2), R ² is,
Represents a hydrogen atom, an alkyl group or an aryl group, Represents a cyclic amino group. ) Is an electron-donating group. (4) When performing conversion of light wavelength using a laser beam and a nonlinear optical material, the above (1),
A method of converting a light wavelength using the organic nonlinear optical material according to (2) or (3).

The group represented by R is a hydrogen atom or an electron-withdrawing group, and examples of the electron-withdrawing group include a nitro group and a cyano group.

The group represented by A is an electron-withdrawing group, and examples of the electron-withdrawing group include phenyl group, 4-nitrophenyl group, 4-
Examples thereof include a cyanophenyl group, a 4-pyridyl group, a chloro group and a bromo group.

The group represented by D is an electron-donating group, and examples of the electron-donating group include an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group and an arylamino group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

Examples of the aryl group include a tolyl group, a 4-methoxyphenyl group, a 4-aminophenyl group, a 4-methylthiophenyl group and the like.

Examples of the alkylthio group include a methylthio group, an ethylthio group and a propylthio group.

Examples of the aryloxy group include a phenoxy group, a 4-methoxyphenoxy group, a 4-aminophenoxy group and a 4-methylthiophenoxy group.

Examples of the arylthio group include a phenylthio group, a tolylthio group, a 4-methoxyphenylthio group, a 4-aminophenylthio group and a 4-methylthiophenylthio group.

Examples of the alkylamino group include a methylamino group, a dimethylamino group, an ethylamino group and a diethylamino group.

Examples of the arylamino group include a phenylamino group, a tolylamino group, a 4-methoxyphenylamino group, a 4-aminophenylamino group, and a 4-methylthiophenylamino group.

The electron-withdrawing group means a substituent having a positive substituent constant σ _p ^o , and the electron-donating group means a substituent having a negative substituent constant σ _p ^o .

The above-mentioned substituent constants are described in "Structure-Activity Relationships of Drugs-Guidelines for Drug Design and Study of Mechanism of Action", Supplementary Issue No. 122, "Chemical Areas", edited by the Society for Structure-Activity Relationships, pages 95-111, Nankodo Publishing Co. "Substitute Student Constants for Correlation Analysis in Chemistry and Biology," by Corwin Hansch and Albert Leo.
(Substituent Constants for Correlation Analysis i
n Chemistry and Biology) 69 to 161 page Represents the values shown in John Wiley and Sons.

The following shows specific examples of the compound used in the present invention,
The present invention is not limited only to these.

The compound of the present invention is a general method for synthesizing phthalazines (eg, Heterocyclic Compounds edited by RNCastle, Volume 27, Chapter 2, John Wiley and Sons (Heterocyclic).
Compounds.Vol.27, Chap.2.John Wiley and Sons) 197
It can be synthesized according to 3).

As will be apparent from Examples described later, the nonlinear optical material of the present invention is particularly useful as a material for converting the wavelength of laser light. However, the application of the nonlinear optics of the present invention is not limited to the wavelength conversion element, but can be used for any element that utilizes the nonlinear optical effect. As specific examples of the element in which the nonlinear optical material of the present invention can be used, in addition to the wavelength conversion element, an optical bistable element (optical storage element, optical pulse waveform control element, optical limiter, differential amplification element, optical transistor, A / D Conversion element, optical logic element, optical multivibrator, optical flip-flop circuit, etc.), optical modulation element, and phase conjugate optical element.

The compounds according to the invention are, for example, in powder form, in the form of inclusions of molecules in the host lattice (polymers, inclusion compounds, solid solutions, liquid crystals), in the form of thin layers deposited on a support (Langmere, Blodgett membranes). Etc.), a single crystal form, a solution form, and the like, and can be used as a nonlinear optical material.

Further, the compound of the present invention can be used by binding to a polymer, polydiacetylene or the like in a pendant form.

Details of these methods are described in the above-mentioned work by DJ Williams.

(Examples) Next, the present invention will be described in detail based on examples.

Example 2nd harmonic generation measurement was performed by SKKu
rtz), TTPerry, Journal of Applied Physics (J.Appl.Phy)
s.) Vol. 39, page 3798 (published in 1968) according to the method described in the powder of the compound of the present invention.

 The measurement was performed using the apparatus shown in FIG.

That is, the measurement was performed using pulsed YAG laser light (λ = 1.064).
μm, a beam diameter of ≒ 1 mmφ, and a peak power of ≒ 10 Mw / cm ² ) were used as fundamental waves, and the intensity of the second harmonic was measured by the evaluation apparatus shown in FIG. The measurement was performed by relative comparison with the intensity of the second harmonic of urea. When the intensity was low, visual observation was performed. In particular, in order to distinguish between the emission due to two-photon absorption of the fundamental wave (mainly yellow and red emission) and the second harmonic, a spectroscope was put in and only the second harmonic was measured. Further, in the measurement by the powder method, the main purpose is to judge the presence or absence of non-linearity of the substance, and the intensity ratio is a reference value of the magnitude of the specific linearity.

 The results are shown in Table 1.

(Effect of the Invention) A compound exhibiting SHG activity by these powder methods can be used as a wavelength conversion element by the following method.

1. The above compound is monocrystallized in the core of the fiber, and a wavelength conversion device using glass as a cladding material is prepared. The second harmonic can be generated by inputting a YAG laser beam. Further, as another method, similarly, a waveguide type wavelength conversion element can be prepared to generate the second harmonic. At this time, the Cherenkov radiation method was used as the phase matching method. However, it is not limited to these,
Waveguide-waveguide phase matching is also possible. Wavelength-converted waves are not limited to second harmonics, but are also used for third harmonic, sum and difference frequency generation.

2. Next, the above compound is converted into a single crystal, and a bulk single crystal is cut out from the compound, and a second harmonic can be generated by inputting a YAG laser beam. At this time, an angle phase matching was used as a phase matching method. These bulk single crystals can be used not only outside the cavity of a laser but also within a solid-state laser cavity such as an LD pumped solid-state laser to improve wavelength conversion efficiency. Furthermore, the wavelength conversion efficiency can be increased by arranging it in the resonator of the external resonator type LD.

For the above-mentioned single crystallization, a Bridgman method, a solvent evaporation method, or the like is used.

The wavelength-converted wave is used not only for the second harmonic, but also for the generation of the third harmonic and the sum difference frequency.

[Brief description of the drawings]

FIG. 1 shows a measuring apparatus of the powder method, and the numbers in the figure indicate the following. 1: Powder sample, 2: Basic paper cut filter 3: Spectrometer, 4: Photomul, 5: Amplifier (11): Wavelength 1.064 μm, (12): 0.532 μm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-262627 (JP, A)

Claims (4)

(57) [Claims] 1. A non-linear optical material comprising a compound represented by the following general formula (I). General formula (I) (Wherein, R represents a hydrogen atom or,, -NO _2, -CN, -COR
^{_{1, -SO 2 R 1, -SOR}} 1, -CF 3, -CCl 3, -COOR 1 and halogen atoms (wherein, R ¹ represents a hydrogen atom or an alkyl group,
An alkenyl group, an alkynyl group, an aryl group, an alkoxy group or an aryloxy group is shown. Represents an electron-withdrawing group. A represents an electron-withdrawing group. D represents an electron donating group. ) 2. A nonlinear optical material comprising a compound represented by the following general formula (I). General formula (I) (Wherein, R represents a hydrogen atom or,, .A is -NO ₂ represent an electron withdrawing _{^{group, -CN, -COR 1, -SO 2}} R 1, -SOR 1, -CF
_3, -CCl _3, (wherein, R ¹ represents a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, an aryl group,. Showing an alkoxy group or an aryloxy group) -COOR ¹ and a halogen atom an electron-withdrawing group, excluding the Represents D represents an electron donating group. ) 3. A non-linear optical material comprising a compound represented by the following general formula (I). General formula (I) (In the formula, R represents a hydrogen atom or an electron-withdrawing group. A represents an electron-withdrawing group. D represents R ¹ , -NH ₂ , -NHC.
OCH ₃ , -N (R ² ) ₂ , An electron-donating group selected from --NHNH ₂ and --OR ² (where
R ¹ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an atar group, an alkoxy group or an aryloxy group. ) R ² represents a hydrogen atom or an alkyl group or an aryl group, Represents a cyclic amino group. ) Is an electron-donating group. ) 4. Light that uses the organic nonlinear optical material according to claim 1 or 2 as the nonlinear optical material when the wavelength of light is converted using laser light and the nonlinear optical material. Wavelength conversion method.