JPH04166820A - Non-linear optical material and non-linear optical element - Google Patents

Abstract

PURPOSE:To obtain an optical material, in which an absorbing end is a short wavelength to provide no absorption substantially in a visible region further to show a high non-linear optical effect, by using a specific compound. CONSTITUTION:A material is formed of a compound expressed by a formula I. In the expression A represent an acceptor quality substituent, X represents O, S, NH and Y represents CH, N and Ar 5 or 6 member annulus group, having aromatization. The acceptor quality substituent, represented by A, is a group with Hammett's sigmap value being 0 or more, with 0 most preferable as X and N most preferable as Y. The 5 or 6 member annulus group, having aromatization, represented by Ar, may be the same annulus group and hetero annulus group, and a phenyl group, having substituent, is preferable as Ar. In this way, an optical material, in which an absorbing end is a short wavelength to provide no absorption substantially in a visible region further to obtain high generation of the second harmonic wave, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to organic nonlinear optical materials and organic nonlinear optical elements used for generation of harmonics of laser light, parametric amplification, and the like.

[Background of the Invention] The nonlinear optical effect that appears when a material is irradiated with intense light such as a laser beam can be applied to wavelength conversion, intensity modulation, switching, etc., and in recent years, materials that have this nonlinear optical effect have been developed. Many exploratory studies have been conducted.

Wavelength conversion, especially second harmonic generation based on second-order nonlinear optical effects.
ration.

Hereinafter abbreviated as SHG. ), previously known lithium niobate (LiNbO5) and potassium dihydrogen phosphate (KD
It has been pointed out that organic compounds may have an order of magnitude higher performance than inorganic materials such as P). (For example, "Organic Nonlinear Optical Materials", Masao Kato, supervised by Nakanishihe Department, CMC Corporation.

(published in 1985) The origin of nonlinearity in organic compounds is the intramolecular π electrons, and 2
The following nonlinear molecular polarizability β becomes particularly large when the compound has both an electron-donating group and an electron-withdrawing group.

However, as typified by p-nitroaniline, even if the nonlinear polarization at the molecular level is large, there are many that do not exhibit total<SHG in the crystalline state, or even if they do, the SHG is small. This is due to the fact that the molecular arrangement of highly polar organic crystals tends to have inversion symmetry.

In addition, research into optical recording media is being actively conducted in response to demands for larger capacity and higher density information recording media, but since the recording density of these optical recording media depends on the wavelength of the light source (
As the light source wavelength becomes shorter, the recording density limit increases in inverse proportion to the square of the wavelength. ), there are great expectations for wavelength conversion elements to obtain shorter wavelength light sources.

However, known compounds with high SHG activity, such as 2-methyl-4-nitroaniline, m-nitroaniline, etc., are yellow-colored and have low short-wave light transmittance. It is disadvantageous for this to occur.

Therefore, a nonlinear optical material is desired that has high transmittance in the visible region, particularly in short-wavelength light.

[Object of the Invention] Therefore, the object of the present invention is to provide a novel organic nonlinear optical material and an organic nonlinear optical material that have an absorption edge at a short wavelength, have substantially no absorption in the visible region, and exhibit high nonlinear optical effects. The purpose is to provide devices.

[Structure of the Invention] The above objects of the present invention are: (1) A nonlinear optical material comprising a compound represented by the following general formula [I].

General formula [I] X represents O,5SNH, and Y represents CH,N.

Ar represents a 5- or 6-membered ring group having aromaticity.

] (2) A nonlinear optical element made of the nonlinear optical material described in item (1) above.

achieved by.

The present invention will be explained in more detail below.

In the above general formula [I], the acceptor substituent represented by A is a group having a σρ value of 0 or more as defined by Hammett, such as a nitro group, a cyano group, a succinimide group, a formyl group, an alkoxy A carbonyl group and a dicyanovinyl group are preferred, and a nitro group and a cyano group are particularly preferred.

As X, O is most preferred, followed by S.

As Y, N is most preferable.

The aromatic 5- or 6-membered ring group represented by Ar may be a homocyclic group or a heterocyclic group, and examples of these groups include phenyl group, pyrrolyl=5- group, pyridinyl group. Examples include groups.

Preferred as Ar is a phenyl group having a substituent. As the substituent, a nitro group, a methoxy group, a hydroxy group, and an amino group are preferable.

Specific examples of compounds preferably used in the present invention are shown below, but the present invention is not limited thereto.

The following are exemplified compounds in the margin.These compounds can be easily synthesized by the boat fishing synthesis method.

Hereinafter, methods for synthesizing these compounds will be specifically explained using Exemplary Compound (1) as an example.

Synthesis Example (I') (n) 3 g of (I) and 2.7 g of p-nitroaniline (II) were dissolved in a mixture of 50 ml of ethanol and 80 ml of ethyl acetate and left overnight. The precipitated crystals were collected by filtration to obtain 3.1 g of Exemplified Compound (1).

(m, p, 162-1134°C) It was confirmed by NMR and FD-Mass that the obtained product was Exemplified Compound (1).

The compounds of the present invention can be used in nonlinear optical elements in various forms, such as single crystals, powders, solutions, thin films formed on supports (Langmuir-Blodgett films, vapor-deposited films, etc.), or blended into polymers or liquid crystal molecules. It can be done. It is also possible to use the compound of the present invention as a constituent component of a polymer, or as an clathrate compound or an adduct.

The shape of the element can be a known waveguide shape. For example, as shown in Japanese Unexamined Patent Publication No. 63-77035, there are fiber shapes, flat plate shapes, and shapes in which a single crystal is surrounded by a cladding material.

The nonlinear optical element of the present invention can be used for wavelength conversion of laser light (generation of harmonics, etc.), intensity modulation, switching, and the like.

[Example] Examples are shown below, but the embodiments of the present invention are not limited thereto.

Example 1 A powder method commonly used to determine the 3HG effect (S, Kurtz, T, T, Perry;
J, Apl.

Phys., 39.3798 (19Bg)] was used to evaluate the compounds of the present invention.

As a light source, a Q-switch Nd: YAG laser (USA Quante
l Inter-nationa1 company YG 6
B OA, wavelength 101084n was used to irradiate the powder sample filled in the glass cell, and the generated SHG
The light (532 nm green light) was separated using a filter and a monochromator, and detected using a photomultiplier tube, and the relative value when urea was taken as 1 was determined.

Margin Table 1 below As is clear from Table 1, the compound of the present invention has strong SHG intensity and visible absorption at a relatively short wavelength, so it is an excellent nonlinear optical material that can also be used for blue light. I understand.

Example 2 A single crystal of the compound of the present invention used in Example 1 was formed in a hollow fiber using the Bridgman-Stockberger method [formation conditions, temperature of high temperature furnace: (melting point of compound) + (5 °C), the temperature of the low temperature furnace; (melting point of the compound)
- (20° C.), pulling speed: 1 m+n/hour], a nonlinear optical element was created.

When a YAG laser beam with a wavelength of 10 [i4r+m]1- was inputted from the end face of the fiber, a second harmonic of 532 nm was observed.

[Effects of the Invention] According to the present invention, it is possible to provide an organic nonlinear optical material and an organic nonlinear optical element that have an absorption edge at a short wavelength, have substantially no absorption in the visible region, and can obtain high SHG. can.

Applicant Co., Ltd.

Claims (2)

[Claims] (1) A 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, A represents an acceptor substituent. X represents O, S, NH, and Y represents CH, N. Ar represents a 5- or 6-membered ring group having aromaticity. ] (2) A nonlinear optical element made of the nonlinear optical material according to claim (1).