JP2685828B2 - Organic nonlinear optical material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an organic nonlinear optical material which is important as a material for forming an electro-optical element, an optical harmonic generating element, an optical waveguide, and the like.

(Prior Art) A substance that generates a light component other than the input light with respect to the input light from the outside of the system is attracting attention as a so-called nonlinear optical material. For some of these types of materials, and for nonlinear optical effects, see, for example, the literature (“Organic Nonlinear Optical Materials”).
It is disclosed in Masao Kato and Hachiro Nakanishi's supervision (1985.7.25 1st edition CMC).

As disclosed in this document, there are organic and inorganic nonlinear optical materials. So far, lithium niobate (LiNbO ₃ ), KDP (KH ₂ OP ₄ ), and K
Development of inorganic nonlinear optical materials represented by TP (KTiOPO ₄ ) etc. precedes that of organic materials. This is because the main applications of conventional non-linear optical materials have been considered mainly for wavelength conversion of high-power laser light, etc. This is because it was easy to obtain a single crystal containing

On the other hand, regarding organic nonlinear optical materials, basic researches such as material development and single crystallization, arraying and thinning of the material are currently being conducted, and deviceization is a future theme. It is known that it has a large non-linear optical constant, quick response, high optical damage strength, easy thinning, and easy microfabrication compared to those of Is becoming. Therefore, organic nonlinear optical materials have been attracting attention as promising nonlinear optical materials.

By the way, when considering applications of nonlinear optical materials, it is not possible to overlook optical communication and optical integrated circuits that are advancing with the development of the information society and the rapid progress of semiconductor lasers. The reason for this is that the nonlinear optical effect is used in the basic technology for frequency conversion, optical modulation, and optical deflection of the laser light used as the light source even in optical communication and the like. That is, in optical communication and the like, strong light such as laser light,
Optical harmonic generation that appears based on the interaction with nonlinear optical materials (second harmonic generation: SHG (Second Harmonic Generati
ion), third harmonic generation (Third Harmonic Generatio
This is because the non-linear optical element is formed and used by utilizing phenomena such as n), light mixing, electro-magneto-optical effect, or optical parametric oscillation.

When a nonlinear optical material is used in optical communication or an optical integrated circuit as described above, the nonlinear optical effect should be remarkably exhibited even with a semiconductor laser whose output power density is not so large. Therefore, high conversion efficiency, that is, high nonlinear susceptibility is required. further,
In making a circuit, it is desired that the thinning is easy and the fine processing is easy.

(Problems to be Solved by the Invention) However, none of the above-described inorganic nonlinear optical materials has been obtained that can satisfy the conversion efficiency and workability.

On the other hand, it is noteworthy that the organic nonlinear optical material has the possibility of satisfying the requirements in terms of conversion efficiency and workability as described above.

 Therefore, new organic nonlinear optical materials are desired.

The present invention has been made in view of the above points, and an object of the present invention is to provide a novel organic nonlinear optical material which is excellent as a nonlinear optical material.

(Means for Solving the Problems) In order to achieve this object, the organic nonlinear optical material of the present invention is represented by the following general formula (1): 1,4-di [p-
Alkylphenylamino] anthraquinone (where n is 0 or a positive integer).

(Operation) The organic compound represented by the above formula (1) emits light corresponding to the second harmonic and the third harmonic of the light incident on this substance, as is clear from the experimental results described later. . Furthermore, this substance can be synthesized with good reproducibility, and harmonic generation also occurs with good reproducibility.

(Examples) Examples of the organic nonlinear optical material of the present invention will be described below.

Synthesis Example of Organic Nonlinear Optical Material First, as an example, an example of the synthesis method of the organic compound of the present invention represented by the following formula (2) will be described. However, it should be understood that the names of chemicals used, numerical conditions, treatment methods, and the like described in the following synthesis examples are merely examples.

First, 2.4 g of quinizarin, 10 g of p-butylaniline, 1 ml of hydrochloric acid and 0.5 g of boric acid are mixed and the mixture is heated to a temperature of 85 ° C. To this, 0.5 g of zinc powder is added and reacted at a temperature of 100 ° C. for 5 hours while stirring. Then, this is left to cool and then methanol is added thereto, whereby the product precipitates. The product is filtered off, washed with further methanol and water and dried.
It is purified by the recrystallization method. In this way, the organic compound 1,4-di [p-butylphenylamino] anthraquinone represented by the above formula (2) is obtained. This material has a width and thickness of 100-200 μm and a length of approximately
It was a 1 mm rod-shaped crystal. The following formula (3) is a reaction formula showing the above-mentioned synthesis method.

Elemental analysis and FTIR analysis of organic compounds synthesized as described above
Each was identified by an (infrared) spectrum.

 The results of the elemental analysis were as shown below.

C: 81.30 H: 6.78 N: 5.61 The calculated values are C: 81.24, H: 6.82, and N: 5.57.

In addition, the result of measurement of infrared absorption spectrum is wavenumber 3450
cm ^-1 and around 1260cm aromatic around ^-1 absorption of a secondary amine,
Absorption of butyl in the vicinity of a wave number of 2900 cm ^-1, absorption of a carbonyl group was observed respectively in the vicinity of a wave number of 1630 cm ^-1.

Investigation result of non-linear optical effect An optical harmonic generating element was produced using the organic compound 1,4-di [p-butylphenylamino] anthraquinone obtained in the above-mentioned synthesis example, and it was confirmed whether or not an optical harmonic was generated. .

First, with regard to the fabrication of the element, in the case of this embodiment, it is performed as described below.

Two glass plates having a size of 13 x 38 mm and a thickness of 0.8 mm are prepared, a gap of 0.1 to 0.3 mm is provided between these glass plates, and an organic compound synthesized as described above is sealed in the gap, and the element is manufactured. Get. The size of the glass plate and the size of the gap between the gas plates are examples and can be changed according to the design.

Next, regarding a device for measuring the presence or absence of generation of harmonics, in the case of this embodiment, a device as shown below is used. FIG. 1 is a block diagram schematically showing this measuring apparatus.
Obviously, the measuring device may have other configurations.

In FIG. 1, reference numeral 11 denotes a laser light source that emits laser light. As the laser light source in this embodiment, an Nd: YAG laser (having a wavelength of 1064 nm and a peak output of 16 KW) is used. 13
Denotes a condenser lens, 15 denotes a spectroscope, 17 denotes a photomultiplier tube, 19 denotes a current amplifier, 21 denotes an integrator, and 23 denotes a recorder.
Reference numeral 25 denotes a synchronization circuit for synchronizing the laser light source 11 and the integrator 21.

In the case of this embodiment, the prepared sample element is irradiated with the laser light condensed by the condenser lens 13 of the laser light source 11 from the direction perpendicular to the main surface of one glass substrate of the sample element. (Refer to FIG. 1)
In the figure, reference numeral 31 denotes a sample element. ).

The principle of the measurement is as follows. The scattered light from the sample element 31 is separated by the spectroscope 16, and this spectroscopic light is converted into a photomultiplier tube.
Light is received by 17. The spectroscope 15 has a variable resolution, and in this embodiment, scans sequentially at a certain resolution over a wavelength of 300 to 900 nm. Then, the information indicating the wavelength band at that time (indicated by Ss in FIG. 1) is recorded by the recorder.
Output to 23 each time. After the current corresponding to the received light is amplified by the current amplifier 19, the current is averaged by the integrator 21 synchronized with the laser oscillation, and the output from the integrator 21 is recorded by the recorder 23. In this way, a scattered light spectrum is obtained.

2 and 3 are diagrams showing scattered light spectra obtained in this way, and particularly FIG. 2 shows the resolution of the spectroscope.
Figure 3 shows the THG spectrum measured as 3 nm.
It is a figure which shows the SHG spectrum measured at a resolution of 6 nm. In each figure, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit).

As is clear from FIGS. 2 and 3, the sample element 31
From this, it was found that a sharp spectrum appears only at the wavelength of 355 nm and at the wavelength of 532 nm. Wavelength 355nm
The spectrum of corresponds to the third harmonic of the incident light having a wavelength of 1064 nm, and the spectrum of the wavelength of 532 nm corresponds to the second harmonic of the incident light.Thus, the organic compound according to the present invention has nonlinear optical characteristics. You know that you have.

The organic nonlinear optical material of the present invention emits a large SHG, which is considered to be due to the structure of the crystal having no inversion symmetry center.

Incidentally, in the above-mentioned examples, the substance in which n in the general formula (1) is 3 is explained, but substances other than n in 3 are considered to show the same characteristics as the examples. Further, when n is 14 or more, the substance becomes amphipathic in molecule, and thus it can be expected to be suitable for thin film production by the Langmuir-Blodgett method.

(Effects of the invention) As is apparent from the above description, the organic compound according to the present invention can be said to be a novel non-linear optical material because it satisfactorily emits higher harmonics of SHG and THG, and thus higher harmonics. It contributes to the realization of useful nonlinear optical elements such as generating elements.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an apparatus used for measuring optical harmonic generation characteristics in order to confirm whether or not the organic compound according to the present invention exhibits a nonlinear optical effect, and FIG. Is a diagram showing a THG spectrum of the organic nonlinear optical material of the present invention, and FIG. 3 is a diagram showing an SHG spectrum of the organic nonlinear optical material of the present invention. 11 Laser light source 13 Condenser lens 15 Spectroscope 17 Photomultiplier tube 19 Current amplifier 21 Integrator 23 Recorder 25 Synchronous circuit 31 Sample element.

Continuation of the front page (56) References JP-A-63-291039 (JP, A) JP-A-2-7302 (JP, A)

Claims (1)

(57) [Claims] 1. An organic nonlinear optical material represented by the following general formula (1) (where n is 0 or a positive integer).