JP2727764B2 - Nonlinear optical material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical parametric oscillation,
The present invention relates to a novel nonlinear optical material that is important in an optical signal processing system such as harmonic generation and optical switching.

[0002]

2. Description of the Related Art Nonlinear optical materials, which are considered to play an important role in optical communication technology, exhibit functions such as optical mixing, parametric oscillation, and optical harmonic generation based on the nonlinear optical response of the material. Conventionally, KH ₂ PO ₄ , NH ₄ H ₂ PO
Inorganic crystals such as ₄ have been used. However, these materials have not yet met the requirements of the aforementioned applications due to deliquescence, low nonlinear susceptibility and low destruction threshold. In addition, the first and second-order electro-optic effects that can be used for optical switching are generated from the same nonlinear polarization as the second- and third-order nonlinear optical effects, respectively, so that the same material may be used. In the frequency region, the inorganic material has a problem of causing chirping. Organic nonlinear optical materials using π-electron polarization have been studied and developed widely in various fields because of their superior nonlinear optical constants than inorganic materials, and generally have no deliquescent and high breakdown threshold. ing. For recent achievements, see, for example, Nonlinear Optical Properties of Organic Molecular and Crystals (Nonlinear
Optical Properties of Org
anic Molecules and Crysta
ls) "Vol. 1 and Vol. 2, D. S. Chem
la, J. et al. Zyss ed. (1987 Academic
Press).

[0003] However, a material having a nonlinear optical constant large enough to achieve a desired purpose with a laser having a small output such as a semiconductor laser has not been found, and further development of a new material is strongly demanded. .

[0004]

SUMMARY OF THE INVENTION The present invention provides a novel organic nonlinear optical material having a high nonlinear optical constant.

[0005]

The present invention provides a compound of the general formula (I)

Embedded image (Where Z is an alkyl group having 1 to 10 carbon atoms,
10 alkoxy groups, aryl groups, aryloxy groups,
Aralkyl groups, aralkyloxy groups, haloalkyl groups,
A chlorine atom or a bromine atom, and n is an integer of 1 to 5), and a nonlinear optical material comprising a composition containing the compound.

In the present invention, a benzal indanone compound represented by the above general formula (I) is used, and the benzal indanone compound is described in detail in, for example, Organic Reaction Vol. Can be easily synthesized by aldol-type condensation of 1-indanone and benzaldehyde having an appropriate substituent.

The compounds represented by the above general formula (I) include, for example, 2'-ethoxybenzal-1-indanone,
3'-methoxybenzal-1-indanone, 4'-phenoxybenzal-1-indanone, 2 ', 3'-dimethoxybenzal-1-indanone, 2', 5'-dimethoxybenzal-1-indanone, 3 ', 4'-diethoxybenzal-1-indanone, 4'-benzyloxybenzal-1-indanone, 2', 3'4'-trimethoxybenzal-1-indanone, 2'-methylbenzal-1
-Indanone, 4'-methylbenzal-1-indanone, 4'-ethylbenzal-1-indanone, 4'-phenylbenzal-1-indanone, 2'-trifluoromethylbenzal-1-indanone, 4'-chlorobenzal- 1-indanone, 2 ', 3'-dichlorobenzal-
1-indanone, 2 ', 4'-dichlorobenzal-1-
Indanone, 3 ', 4'-dichlorobenzal-1-indanone, 4'-bromobenzal indanone and the like.

In the general formula (I), Z is a methoxy group, and when n = 3, Z is bonded to positions 2 ', 3' and 4 ', and when n = 2, Z is 2' and 5 ' Or a compound bonded to the 2 'and 3' positions, and when n = 1, a compound bonded to the 3 'position or in the general formula (I), where Z is a chlorine atom or a bromine atom, and both are at the 4' position Are preferred. For example, 3'-methoxybenza-1-indanone, 2 ', 5'-dimethoxybenza-1-indanone, 2', 3'-dimethoxybenza-1-indanone, 2 ', 3', 4'-trione Methoxybenzal-1-
Indanone, 4'-chlorobenzal-1-indanone,
4'-bromobenzal-1-indanone is preferred.

The nonlinear optical material according to the present invention may be a composition in which the compound represented by the above general formula (I) is dispersed or dissolved in a polymer compound. As the polymer compound, for example, methyl (meth) acrylate (indicating methacrylate or acrylate; the same applies hereinafter), ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid, styrene , Vinyltoluene, divinylbenzene, vinyl chloride, β-hydroxyethyl (meth)
Homopolymer or copolymer of monomer such as acrylate,
Polyester, polyamide, polyurethane, polycarbonate, cellulose ester, polyether and the like are used. The compound represented by the general formula (I) may be mixed with the monomer corresponding to the compound represented by the general formula (I) and then polymerized by the action of heat or light to form a composition. May be dissolved and mixed using an appropriate solvent, and then the solvent may be removed to obtain a composition. In the former case, the nonlinear optical performance can be improved by performing boring during the polymerization, or by performing boring after obtaining the composition for both the former and the latter. Alternatively, the compound represented by the above general formula (I) is heated to a temperature equal to or higher than the melting point in the presence of a DC electric field and melted, and then slowly or rapidly cooled while maintaining the electric field, whereby the orientation direction of the molecules is controlled. A single crystal or molecular glass having high nonlinear optical performance can be obtained.

[0010]

The compound of the present invention has a carbonyl group as an acceptor group in its structure, and these are styryl π
Since it is conjugated with an electronic system, a large dipole moment is generated by charge transfer in an excited state, and has a high hyperpolarizability, thereby obtaining a high nonlinear optical effect.

[0011]

The present invention will be further described with reference to examples. A synthesis example of the benzal-1-indanone compound is shown below.
3'-methoxybenzal-1-indanone (compound 1)
M-methoxybenzaldehyde (2.57 g, 1
8.9 mmol), 1-indanone (2.5 g, 18.
9 mmol), methanol (15 ml) and 35% N
An aOH aqueous solution (0.5 ml) was placed in a 100 ml eggplant-shaped flask, a piece of zeolite was added, and a condenser for cooling was attached, followed by heating under reflux for about 1 hour. When allowed to cool, crystals appeared, which were filtered off and washed well with methanol. The yield was about 4.5 g (95%). The product structure is nm
Confirmed by r, ir and absorption spectrum.

2 ', 5'-Dimethoxybenzal-1-indanone (Compound 2), 2', 3'-Dimethoxybenza-1-indanone (Compound 3), 2 ', 3', 4'-
Trimethoxybenzal-1-indanone (compound 4),
4'-chlorobenzal-1-indanone (compound 5),
4'-Bromobenzal-1-indanone (Compound 6) was also synthesized in the same manner. Comparative Examples, Examples 1 to 6 Absorption maximum wavelength (λm
ax) and the second harmonic generation efficiency (S
Table 1 shows the results of the HG efficiency and the intensity ratio of the second harmonic when urea is set to 1. The outline of the powder method is described in "Journal of Abrid Physics"
Applied Physics) Vol. 36 (1
968) 3798-3813. A sample powder classified to a particle size of 50 μm to 150 μm is sandwiched between non-fluorescent slide glass (Matsunami Glass) and a pulse Nd: YAG laser manufactured by Spectro Laser Systems (SL303, output 850 mJ, half width 15 ns, output 50 MW per pulse). , A beam diameter of 9.5 mm, a wavelength of 1.064 μm, and a repetition frequency of 10 Hz). The intensity of the generated second high frequency of 532 nm was measured by a photomultiplier through an infrared filter and a UV filter.

[0013]

[Table 1]

Examples 7 to 18 For the following compounds synthesized by the same method as described above, the absorption maximum wavelength and the presence / absence of generation of the second harmonic were measured at 532 nm using the same pulse Nd: YAG laser as in Examples 1 to 6. Table 2 shows the result of visually determining whether or not the green light is generated.

[0015]

[Table 2] * Here, "weak" indicates about the level of urea, "strong" indicates about the level of 2-methyl-4-nitroaniline, and "medium" indicates the second harmonic generation intensity at an intermediate level.

[0016]

According to the present invention, a nonlinear optical material having high optical nonlinearity can be obtained.

Claims (9)

(57) [Claims] 1. A nonlinear optical material comprising a compound represented by the general formula (I). Embedded image (Where Z is an alkyl group having 1 to 10 carbon atoms, 1 to 1 carbon atoms)
0 is an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, an aralkyloxy group, a haloalkyl group, a chlorine atom or a bromine atom, and n is an integer of 1 to 5) 2. A nonlinear optical material comprising a compound in the general formula (I) wherein Z is a methoxy group, n = 3, and Z is bonded to the 2 ', 3' and 4 'positions. 3. A nonlinear optical material comprising a compound of the formula (I) wherein Z is a methoxy group, n = 2, and Z is bonded to the 2 ′ and 5 ′ positions. 4. A nonlinear optical material comprising a compound represented by the general formula (I) wherein Z is a methoxy group, n = 2, and Z is bonded to the 2 ′ and 3 ′ positions. 5. A nonlinear optical material comprising a compound of the formula (I) wherein Z is a methoxy group, n = 1, and Z is bonded to the 3 ′ position. 6. A nonlinear optical material comprising a compound of the formula (I) wherein Z is a chlorine atom or a bromine atom, and both are bonded at the 4 'position. 7. A nonlinear optical material comprising a composition containing the compound represented by the formula (I) according to claim 1. 8. A nonlinear optical material comprising a composition containing the compound according to claim 2, 3, 4, or 5. 9. A nonlinear optical material comprising a composition containing the compound represented by claim 6.