JP2937282B2 - Third-order nonlinear optical material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a third-order nonlinear optical material useful in fields such as optoelectronics, optical information processing, and optical communication.

[0002]

2. Description of the Related Art A nonlinear optical material is a material that exhibits a second-order or higher nonlinear response under a strong electric field of laser light, and is an important material in optical signal processing such as frequency conversion, oscillation, and switching. is there. In particular, tertiary nonlinear optical materials are attracting attention as key materials in next-generation optical communication and information processing that fully exhibit the excellent characteristics of light, such as high speed and parallelism.

[0003] Among these nonlinear optical materials, organic nonlinear optical materials are particularly important because some of them have high-speed response and a large nonlinear optical constant as compared with conventional inorganic nonlinear optical materials.

At present, organic non-linear materials having a large tertiary effect include polydiacetylene [particularly, PTS: 2,4-hexadiyne-1,6-bis (p-toluenesulfonate)] and π-conjugated materials represented by polyacetylene. Molecular systems and aminonitrostilbenes (especially DEANS:
N, N-diethyl-4-amino-4'-nitrostilbene), which are classified into two types of low molecular weight systems in which donors and acceptors are asymmetrically substituted.

The non-linearity of the π-conjugated polymer system is based on the polarization of free electrons in the valence band. Therefore, the defect is very similar to that of an inorganic semiconductor, that is, the response speed decreases due to the resonance effect based on a narrow band gap. Can not escape. Further, the donor-acceptor asymmetrically substituted low-molecular-weight system exhibits the same drawbacks as an attempt to increase the effect beyond the current state (DEANS) by increasing the wavelength of the absorption band due to intramolecular charge transfer.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an organic nonlinear optical material exhibiting a high-speed and high-response optical nonlinear response. The present invention relates to a third-order nonlinear optical material containing a compound represented by the following general formula [I].

[0007]

Embedded image

(Where R ₁ is an alkoxy group, a hydroxyl group,
Represents a phenyl group having any one of a dialkylamino group, an amino group, a cyano group, an alkyl group, a nitro group, and a halogen atom as a substituent, or simply a phenyl group or a hydrogen atom; and R ₂ , R ₃ , R ₄ , R ₅ represents any one of a hydrogen atom, an alkoxy group, a hydroxyl group, a dialkylamino group, an amino group, a cyano group, an alkyl group, a nitro group, and a halogen atom. )

The main feature of the organic nonlinear optical material according to the present invention is that it has a longer third-order nonlinear optical effect than ever before, while suppressing a longer wavelength of absorption to prevent a decrease in response speed. . This is because, when trying to increase the nonlinear optical effect, the disadvantage of the prior art that the absorption becomes longer due to the expansion of π conjugation and the increase in charge transfer, the planarity of the molecule is good in the para position of benzene, By symmetrically introducing a phenanthro [9,10-d] imidazole group having a wide conjugated system and a strong electron-donating property, absorption can be kept at a short wavelength even when a π-conjugated system is widened, and a benzene ring at the center can be obtained. The third-order nonlinear optical effect was improved by increasing the electron density to

[0010]

Embodiments are described below. Synthesis Example 1

[0011]

Embedded image

[0012] 200 ml of phenanthroquinone 0.01 mol, terephthalaldehyde 0.005 mol and ammonium acetate 0.16 mol
Of glacial acetic acid and heated under reflux for 1 hour. After cooling, the mixture was poured into 1 liter of ice water and neutralized with ammonia to precipitate crystals. Then, it was filtered, washed, dried, and recrystallized from dimethylformamide to give 1,4-bis (phenanthro [9,10-
d] Imidazole-2) benzene was obtained.

Example 1 1,4-bis (phenanthro [9,
10-d] imidazole-2) Using benzene, FIG.
The third-order nonlinear optical characteristics were measured using the polarization / nonlinear constant measuring apparatus shown in FIG. The light source has a Q switch Nd: Y
Using a dye laser 2 excited by the third harmonic (355 nm) of the AG laser 1, this output light is divided into pump light 11 and probe light 21 and is linearly polarized by the polarizers P1 and P2, respectively. After passing through the sample 3, the probe light 21 is quenched by the analyzer P3. Here, the sample 3 was irradiated with the polarization plane of the pump light 11 and the probe light 21 at an angle of 45 °. The light transmitted through the analyzer P3 was detected by the photomultiplier tube 5 through the spectroscope 4. As a result, a third-order nonlinear optical effect 120 times that of CS ₂ was observed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a polarization / nonlinear constant measuring apparatus.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/35 504 CA (STN)

Claims (1)

(57) [Claims] 1. A third-order nonlinear optical material comprising a compound represented by the following general formula [I]. Embedded image (However, R ₁ is an alkoxy group, a hydroxyl group, a dialkylamino group, an amino group, a cyano group, an alkyl group, a nitro group,
A phenyl group having any one of halogen atoms as a substituent, or simply a phenyl group or a hydrogen atom,
R ₂ , R ₃ , R ₄ , and R ₅ represent any one of a hydrogen atom, an alkoxy group, a hydroxyl group, a dialkylamino group, an amino group, a cyano group, an alkyl group, a nitro group, and a halogen atom. )