JPH0684329B2 - Non-linear optical element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is characterized by using a novel compound having an excellent nonlinear optical effect and a group of compounds having an excellent nonlinear optical effect including these novel compounds as an element. Non-linear optical element.

Non-linear interaction when irradiating a substance with laser light is known as a so-called non-linear effect, and causes phenomena such as generation of second and third harmonics, Kerr effect, and parametric amplification.

This non-linear effect is applied to the generation of short-wavelength laser light, information processing, optical communication, etc. Therefore, development of a device material having excellent non-linear effect and excellent durability is desired. .

[Conventional technology and its problems]

Conventionally, some substances having a relatively strong nonlinear optical effect are known. For example, urea, 2-methyl-4-nitroaniline (MNA) and the like.

These organic substances are excellent materials in that they have a large non-linear effect and various molecular designs are possible, but they are susceptible to optical damage, and no satisfactory substances have been found yet.

The present inventors have conducted various studies on the properties of a group of diolefin compounds, and have discovered that these compounds are substances having excellent non-linear effects. Normally, the nonlinear optical effect of a substance is evaluated by irradiating the powder with a strong laser beam and measuring the generation of secondary, tertiary, etc. higher harmonics, but some diolefin compounds are irradiated with YAG laser. It has been found that a strong third harmonic is generated at and there is little optical damage.

Based on this finding, the present inventors synthetically evaluated a wide range of peripheral substances including many novel substances, and as a result, a group of substances have excellent non-linear effects and excellent durability. It was discovered that the present invention was achieved.

The novel diolefin compound having the excellent non-linear effect, which is the first feature of the present invention, is represented by the following general formula (I).

[However, in the formula, R and R'are And R and R'are the same or different groups.

Ar is Indicates. Examples of preferable substances contained in this substance group include the following substances.

Compound represented by general formula (I) These materials can be synthesized by conventional synthetic methods well known to those skilled in the art. The synthesis method is illustrated below,
It is not limited to these methods.

(A) Formula (I) Synthesis example of substance The present invention also provides a non-linear optical element made of a material group having the following basic structure including the above material group.

[However, in the formula, R and R'are And R and R'are the same or different groups.

Ar is Indicates. ] These substances generate strong third harmonics by irradiation with YAG laser, for example. Further, a substance that forms an asymmetric crystal also generates a second-order harmonic wave, and is therefore useful as a material for a nonlinear optical element.

〔Example〕

 The present invention will be described below with reference to examples.

First, a synthesis example of the novel diolefin compound of the present invention will be shown.

Synthesis example 1 24.33 g (150 mmol) of p-diacetylbenzene and 12.58 g (150 mmol) of ethanedithiol were dissolved in 450 ml of benzene, 8.70 g of zinc chloride was further added, and the mixture was stirred with a stirrer while blowing hydrogen chloride gas. When all the zinc chloride was dissolved, the blowing of hydrogen chloride gas was stopped and the mixture was further stirred overnight at room temperature. After the reaction, the mixture was allowed to stand and the upper benzene layer was separated from the lower aqueous layer by decantation, and the benzene solution was concentrated to obtain 28.6 g of a crude product. Further recrystallization from ethanol gives 20.11 g as white plate crystals.
Was obtained.

100 ml of 5.18 g (21.7 mmol) of the monoacetyl compound obtained in (1) and 3.06 g (21.7 mmol) of p-chlorobenzaldehyde
After dissolving in 10 ml of methanol, 14 ml of 10% sodium hydroxide solution was added, and the mixture was stirred at room temperature overnight. After the reaction, the yellowish white precipitated product was separated, and then washed with water and methanol in this order. Further recrystallization from acetonitrile gave 5.66 g of an aldol condensate as pale yellowish white plate crystals.
72% yield [1-acetyl-4- (4-chlorobenzalacetyl)
Synthesis of benzene] To 5.49 g (15.2 mmol) of dithiane obtained in (2), 70 ml of acetone and 5 ml of water were added and dissolved by heating, and then methyl iodide was added.
1.5 ml was added and refluxed for 13 hours. 2 ml of methyl iodide was added to this reaction system, and the mixture was further refluxed for 25 hours. After the reaction, the precipitated crystals were separated and washed with acetone to obtain lemon-colored crude crystals. Further, the liquid was concentrated, 1 ml of methyl iodide was further added, and the mixture was refluxed for 8 hours to obtain further lemon-colored crystals. This crystal was separated, washed with acetone, and recrystallized from acetonitrile together with the crude crystal obtained above to obtain a lemon-colored plate crystal.

Yield 1.95g (45.0%), mp 188 ℃ After dissolving 150 mg (0.527 mmol) of 1-acetyl-4- (4-chlorobenzalacetyl) benzene obtained in (3) and 74.1 mg (0.553 mmol) of p-cyanobenzaldehyde in 5 ml of methanol, 0.75 ml of A 10% K NaOH aqueous solution was added, and the mixture was stirred with a stirrer for 43 hours at room temperature. After the reaction, the pale yellow-brown precipitate was separated and washed with water, methanol, and chloroform in this order to obtain a lemon-colored powder (crude yield: 171 m
g). The crude product was recrystallized from xylene to obtain lemon-colored fine crystals.

mp290-294 ℃ (decomposition) Yield 124mg (59.0%) Synthesis example 2 1-Acetyl-4- (4-) obtained in (3) of Synthesis Example 1.
Chlorbenzal acetyl) benzene 150mg (0.527mmol)
And p-nitrobenzaldehyde 83.6mg (0.553mmol) 5
After dissolving in methanol (ml), 0.75 ml of 10% NaOH aqueous solution was added, and the mixture was stirred at room temperature for 29 hours with a stirrer. After the reaction, the precipitated solid was separated, and then washed thoroughly with water and methanol in this order to obtain a lemon-colored powder (crude yield: 203 m
g). The crude product was recrystallized from xylene to obtain yellow needle crystals.

mp274.0-276.0 ° C. Yield 95 mg (43.2%) Example FIG. 1 shows an outline of an apparatus system for measuring the nonlinear optical effect. This is a variation of the method reported by Kurtz et al. In FIG. 1, the light source 1 has a Q-switched Nd: YAG
A laser was used. Repetition is 10Hz, pulse width is 10nsec
The light 3 having a pulse output of about 10 MW was used after being appropriately attenuated. The measurement angle θ was π / 4, and the distance between the sample and the spectroscope was 50 cm. In addition, in each measurement, the intensity of the higher harmonic wave of the sample was made sure to be compared with the intensity of the reference sample so that the harmonic intensity of the sample did not change due to a difference in laser output at each time. Sample 2 was ground as evenly as possible using a mortar, and it was confirmed with an optical microscope that the particle diameter r was 10 to 50 μm in any sample. As shown in FIG. 2, this powder 2 was placed on a slide glass 4, fixed with a tape 5, and fixed on a sample table. Harmonics generated by vertically irradiating the sample with the laser beam 3 were condensed, and after being separated by 7 were detected by the photomultiplier tube 8 and the electric signal thereof was observed by the oscilloscope 9. In addition, wavelength scanning was performed and it was confirmed that they were SHG (second harmonic) and THG (third harmonic).
SHG and THG were measured using urea as a standard sample, and the sample was evaluated using the intensity ratio. 6 is an infrared filter, 7
Is a spectrometer and 10 is a convex lens.

The results are shown in Table 1.

[Brief description of drawings]

FIG. 1 is a schematic view of a non-linear optical effect measuring device used in Examples, and FIG. 2 is an enlarged view of this sample portion. 1 ... Light source 2 ... Sample 9 ... Oscilloscope

Claims (2)

[Claims] 1. A diolefin compound having a non-linear optical effect represented by the following general formula (I). [However, in the formula, R and R'are And R and R'are the same or different groups. Ar is Indicates. ] 2. A non-linear optical element comprising a crystal of a diolefin compound represented by the following general formula (I) and utilizing its non-linear optical effect. [However, in the formula, R and R'are And R and R'are the same or different groups. Ar is Indicates. ]