JP2507901B2 - Sulfur-containing organic third-order nonlinear optical material - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a third-order nonlinear optical material, and more particularly to a third-order nonlinear optical material containing a specific sulfur-containing organic compound.

[Prior art and its problems]

It is known that materials such as certain organic compounds exhibit third-order nonlinear optical characteristics, and these materials are also generally called nonlinear media. However, known organic compound molecules generally have a large absorption in the visible light wavelength range and do not exhibit a large third-order molecular hyperpolarizability (or third-order supramolecular polarizability), and thus have low utility as a third-order nonlinear optical material. . Therefore, realization of a practical material having a large third-order nonlinear optical effect is desired.

[Means for solving problems]

The inventors of the present invention have found that cyanocobalamin (vitamin B ₁₂ ) exhibits excellent performance as a result of repeated research for a material excellent in the effect as a third-order nonlinear optical material, and based on this finding. A patent application has already been filed (Japanese Patent Application No. 2-24235).

As a result of further studies, the present inventor has found that sulfur-containing organic compounds, trithia [5] heterohelicene (or [5] thiahelicene) and tetrathia [7].
It was found that heterohelicene (or [7] thiahelicene) exhibits almost no absorption in the visible light wavelength range and has a large third-order molecular hyperpolarizability, and thus exhibits an excellent effect as a third-order nonlinear optical material. . That is, the present invention relates to trithia [5] heterohelicene (hereinafter referred to as 5TH) and tetrathia [7] heterohelicene (hereinafter referred to as 7T).
And a sulfur-containing organic third-order nonlinear optical material containing at least one of H).

In the present invention, 5TH and / or 7
TH is used in various forms such as a solution state dissolved in a solvent such as benzene; a state in which a transparent resin such as polymethylmethacrylate or polystyrene is doped; a vapor-deposited film, a solid state such as a single crystal. The concentration of 5TH in solution is
Usually 0.05 to 1.5% by weight (hereinafter simply referred to as "%")
The concentration of 7TH is usually 0.05 to 0.5%.
Is. A more preferable concentration for both is 0.2 to 0.5.
%.

As a solvent, 5TH and / or 7T
There is no particular limitation as long as it can dissolve H. Specific examples include benzene, dichloromethane, dioxane and the like.

The degenerate four-wave mixing method used for evaluating the molecular hyperpolarizability of the sulfur-containing organic third-order nonlinear optical material of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a measuring optical system by the degenerate four-wave mixing method. Circularly polarized pulsed light with a wavelength of 1064 nm (rated output 1.1 J / pulse) emitted from the Nd / YAG laser (1) is passed through the slit (2) to KD ^* P.
Lead to optical crystal (3), pulse width about 7 at wavelength 532nm
Get ns of light. Therefore, the light exiting the KD ^* P optical crystal (3) contains a mixture of light having a wavelength of 1064 nm and light having a wavelength of 532 nm. Therefore, the light having a wavelength of 1064 nm is absorbed and removed by the infrared absorption filter (4), and the , Using the remaining light having a wavelength of 532 nm. The light having a wavelength of 532 nm that has passed through the infrared absorption filter (4) is split into two by the semi-transparent mirror (5 ₁ ). While the light is divided into two parts by yet another half mirror (5 _2), one light is reflected by the total reflection mirror (6 _1), lambda / 4 plate (8 ₁₎ perpendicular to the paper surface The sample (9) polarized in different directions and containing 5TH and / or 7TH as pump light (P ₁ ) is irradiated. Another one of the lights 2 divided by half mirror (5 ₂₎ is reflected by the total reflection mirror (6 _2), lambda / 4 plate (8
₂ ) is polarized in the direction perpendicular to the paper surface, and the pump light (P
Samples containing 5TH and / or 7TH as ₂ ) (9)
Is irradiated. The other light split into two by the semi-transparent mirror (5 ₁ ) is reduced to 1/10 by the ND filter (7 ₁ ) and split into two again by the semi-transparent mirror (5 ₃ ). One of the light beams split by the semi-transparent mirror (5 ₃ ) is polarized by the λ / 4 plate (8 ₃ ) in a direction perpendicular to the paper surface, and contains 5 TH and / or 7 TH as probe light (Pr) (9) Is irradiated. The other one of the lights split by the semi-transparent mirror (5 ₃ ) is 1/1 by the ND filter (7 ₂ ).
After being reduced to 000, it is reflected by the total reflection mirror (6 ₅ ),
It is introduced into the streak camera (10) and detected as reference light (R). In the illustrated apparatus, pump light (P ₁ ), pump light (P ₂ ) and probe light (Pr)
The optical path length of the sample (9) is based on the semi-transparent mirror (5 ₁ ).
Are arranged so that the respective optical path length differences up to are 2 mm or less.

In such a state, when the pump light (P ₁ ), the pump light (P ₂ ) and the probe light (Pr) are simultaneously irradiated to the sample (9), the light from the sample becomes the signal light (S). Occurs. This signal light (S) is a λ / 4 plate (8 ₃ ).
After passing through the semi-transparent mirror (5 ₃ ), the light is reflected by the total reflection mirrors (6 ₃ ) and (6 ₄ ) and introduced into the streak camera (10). The intensity ratio of the pump light (P ₁ ), the pump light (P ₂ ), and the probe light (Pr) on the sample (9) in the illustrated optical system is P ₁ : P ₂ : Pr = 10: 10:
It is 1. The intensities of the signal light (S) and the reference light (R) introduced into the streak camera (10) are the spatial distribution area in the streak camera (10) as the signal light area (A _S ) and the reference light area (A _R). ).

[0010]

According to the sulfur-containing organic third-order nonlinear optical material of the present invention, the following remarkable effects are achieved. (A) The third-order nonlinear optical effect is large. (B) Light damage is small. (C) The medium can be exchanged even in the state of use.

【Example】

The features of the present invention will be further clarified by the following examples.

Examples 1 and 2 and Reference Examples 1 and 2 Using a measurement optical system of the type shown in FIG. 1, the performance as a third-order nonlinear optical material of 5TH and 7TH was investigated. 5
The TH or 7TH was carried out by placing a benzene solution having a concentration of 0.2% in a quartz cell having a thickness of 1 mm, placing the quartz cell at the position (9) in FIG. 1, and detecting the light emitted therefrom. The wavelengths of the signal light and the reference light were 532 nm.

The specific light intensity generated from the sample is the ratio of the signal light area (A _S ) and the reference light area (A _R ) in the streak camera, which is a photodetector in the optical system, I = A _S / A _R
It was expressed by. The ratio light intensity of the solution 5TH or 7TH _{I S}
And _Ib is the specific light intensity of benzene only, 5 TH
Alternatively, the specific light intensity from the 7TH portion is I _h = I _S −I _b
Obtained as. Using this specific light intensity I _h , the specific light intensity I _c of carbon disulfide as a standard sample and the third-order nonlinear susceptibility χ ⁽³⁾ c of carbon disulfide obtained by the same optical system as the standard sample, 5 TH or 7TH third-order nonlinear susceptibility χ
⁽³⁾ h was calculated. Then, after dividing this χ ⁽³⁾ h by the number of molecules in a unit volume and further correcting the local electric field,
a. u. By converting into units (atomic units), a third-order molecular hyperpolarizability was obtained. The third-order nonlinear susceptibility χ ⁽³⁾ c of carbon disulfide was set to 1.7 × 10 ^-12 esu.
(Reference: Proceedings of the 59th Annual Meeting of the Chemical Society of Japan, P545,3
E134, 1990) The results are shown in Table 1 below. As a reference example, Table 1 also shows the results for benzene and carbon disulfide.

Table 1Sample fee Compound Tertiary molecule hyperpolarizability (au)  Example 1 5TH 8.9 × 10⁶ Example 2 7TH 1.8 × 10⁷ Reference Example 1 Benzene 2.7 × 10^Four Reference Example 2 Carbon disulfide 1.3 × 10^Five

From the results shown in Table 1, it is clear that the sulfur-containing organic compound according to the present invention has a third-order molecular hyperpolarizability that is two to three orders of magnitude higher than that of benzene. Also,
It is clear that it has a third-order molecular hyperpolarizability that is one to two orders of magnitude higher than that of carbon disulfide, which has long been known as a compound exhibiting large nonlinearity and is often used as a standard substance.

[0016]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an outline of a measurement optical system by a degenerate four-wave mixing method used for investigating a molecular hyperpolarizability of a sulfur-containing organic third-order nonlinear optical material according to the present invention.

[Explanation of symbols]

(1) ... Nd · YAG laser (2) ... slit (3) ... KD ^* P optical crystal (4) ... infrared absorption filter ₍₅ 1) to ₍₃₎ ... half mirror ₍₆ 1) to ₍₆ 5) ... 532 nm for total reflection mirror _{(7 1) ~ (7 2} ) ... ND filter _{(8 1) ~ (8 3} ) ... λ / 4 plate (9) ... sample (10) ... streak camera _{(P 1)} ... pump light (P ₂ ) ... Pump light (Pr) ... Probe light (S) ... Signal light (R) ... Reference light

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kawamen 289-13 Kotsumi, Kawagoe City, Saitama Prefecture

Claims (1)

(57) [Claims] 1. A sulfur-containing organic third-order nonlinear optical material containing at least one of trithia [5] heterohelicene and tetrathia [7] heterohelicene.