JPH0565277A - Molecular crystal and conversion of wavelength of light using the same - Google Patents

Abstract

PURPOSE:To provide a new compound exhibiting excellent blue-light transmittance, having a molecular orientation suitable for a wavelength conversion element free from inversion symmetry and useful as a non-linear optical material. CONSTITUTION:The compound of formula I (R is alkyl) and a compound corresponding to the compound of formula I wherein at least one H atom is substituted with deuterium atom, e.g. the compound of formula II. The compound of formula I can be produced by the Knoevenagel reaction of 4- alkoxybenzaldehyde with 4-azolidine-2,4-dione.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to novel compounds and molecular crystals useful as nonlinear optical materials. The present invention also relates to a light wavelength conversion method and a light wavelength conversion module using a molecular crystal as a nonlinear optical material.

[0002]

2. Description of the Related Art In recent years, a material having a non-linear optical material-a non-linearity between polarization and an electric field, which appears when a strong optical electric field such as a laser beam is applied, has been attracting attention. Such materials are commonly known as non-linear optical materials,
For example, it is described in detail in the following. "Nonlinear Optical Properties of Organic and Polymeric Material" ACS Symposium Series 233 by David Jay Williams (American Chemical Society 1983) "" Nonlinear Optical Properties of Organic and
Poly-meric Material "ACS SYMPOSIUM SERIES 233 Dav
id J. Williams (American Chemical Society, 1983), "Organic Nonlinear Optical Materials" Masao Kato, Hachiro Nakanishi (CMC, 1985, "Nonlinear Optical Properties of Organic Molecules") And Crystals "Volumes 1 and 2, edited by DS Smura and Jay Jiss (Academic Press, 1987)""Nonline
ar Optical Properties of Organic Mo-lecules and Cr
ystals "vol 1 and 2 edited by DS Chemla and J. Zyss (Ac
Published by ademicPressc).

One of the applications of the nonlinear optical material is a second harmonic generation (SHG) based on the second-order nonlinear effect and a wavelength conversion device using a sum frequency and a difference frequency. So far, those which have been practically used are inorganic perovskites represented by lithium niobate. However, recently, it has become known that a π-electron conjugated organic compound having an electron-donating group and an electron-withdrawing group has various performances as a nonlinear optical material, which greatly exceeds the above-mentioned inorganic substances.

For the formation of higher performance nonlinear optical materials,
It is necessary to arrange compounds having a high nonlinear susceptibility in the molecular state so as not to generate inversion symmetry. It is known that a compound having a long π-electron conjugated chain is useful for the expression of a high non-linear susceptibility, which is one of them, and various compounds are described in the above-mentioned documents. Obviously, the maximum absorption wavelength becomes longer, and the transmittance of, for example, blue light is reduced, which causes damage to the generation of blue light as the second harmonic. This also occurs in the p-nitroaniline derivative, and the fact that the transmittance of the wavelength has a great influence on the efficiency of the second harmonic generation is explained by Alain Azema et al., Proceedings of SPII, Four
Volume 00, New Optical Materials (Alain
Azems et al., Proceedings of SPIE, Volume 400, Now Op
(1983) p. 186. Therefore, the advent of a nonlinear optical material having a high transmittance for blue light is desired. Conventionally, replacement of carbon atoms in the benzene nucleus of nitroaniline with nitrogen atoms has been studied, but satisfactory results have not always been obtained.

Further, the present applicant has found out about a superior method in Japanese Patent Laid-Open Nos. 62-210430 and 62-2.
It was disclosed in Japanese Patent No. 10432. Furthermore, JP-A-62-5
9934, JP-A-63-23136, JP-A-63-
26638, JP-B-63-31768, JP-A-63.
-163827, JP-A-63-146025, JP-A-63-85526, JP-A-63-239427,
JP-A 1-100521 and JP-A 64-56425
Japanese Patent Application Laid-Open No. 1-102529 and Japanese Patent Application Laid-Open No. 1-10253
No. 0, JP-A 1-237625, JP-A 1-2077.
Many materials are disclosed in Japanese Patent Publication No. 24 and the like.

However, as described above, in order to be useful as a second-order nonlinear optical material, the performance in the molecular state alone is insufficient, and the molecular arrangement in the aggregated state has no inversion symmetry. Is mandatory. However, at present, it is extremely difficult to predict the molecular arrangement, and the probability of existence in all organic compounds is not high. Further, when it is used as an element for wavelength conversion, it is necessary to sufficiently consider the arrangement of molecules in the crystal, but most of the above-mentioned ones do not necessarily sufficiently consider the point. Furthermore, until now, no wavelength conversion element using an organic nonlinear optical material has appeared in the world as a product. Possible reasons for this include, for example:

First of all, most compounds rely only on the evaluation of the powder method SHG, and do not consider the relationship between the molecular arrangement in the single crystal and the polarization directions and angles of the incident fundamental wave and the emitted converted wave. .. Further, when a fiber type optical wavelength conversion element is formed by using such a nonlinear optical material as described above, the crystal is not oriented in a direction in which the maximum nonlinear optical constant of each material can be used, so that the optical wavelength conversion element is eventually used. The wavelength conversion efficiency of is not so high. Furthermore, the wavelength conversion efficiency of a light wavelength conversion element increases with the length of the element, but it is difficult to obtain a uniform single crystal with many of the above materials, which makes it unsuitable for making a long light wavelength conversion element. There are also problems.

[0008]

SUMMARY OF THE INVENTION Therefore, a first object of the present invention is to provide a novel compound having a non-linear optical response and an excellent blue light transmittance. The second purpose is
It is an object of the present invention to provide a molecular crystal having a molecular arrangement suitable for a wavelength conversion element having excellent blue light transmittance and no inversion symmetry. A third object is to provide a method that utilizes the responsivity related to the conversion of the light wavelength among the non-linear responsivities.
A fourth object is to provide an optical wavelength conversion module having high wavelength conversion efficiency and capable of easily obtaining the second harmonic in the blue region.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a compound represented by the following formula (1), a molecule represented by the following formula (2), and a deuterium-substituted compound thereof are used. It has been found that the object of the present invention can be achieved by a molecular crystal characterized by being constituted. Formula (1)

[0010]

[Chemical 3]

In the formula, R represents an alkyl group. Examples of the alkyl group include linear and branched ones having 1 to 20 carbon atoms. Preferably 1 to 3 carbon atoms
Is a straight chain, and more preferably methyl. Formula (2)

[0012]

[Chemical 4]

In the formula, X and Y each represent a sulfur atom or an oxygen atom. However, X and Y are not the same. The compounds of formula (1) and formula (2) can be generally synthesized by the following method. That is, it can be obtained by the Knoevenagel reaction of 4-alkoxybenzaldehyde and thiazolidine-2,4-dione. As the solvent, alcohols, ethers, nitriles, amides and the like can be used, and as the catalyst, acid or base can be used. The reaction temperature may be in the range of -100 ° C to 150 ° C,
Preferably -78 ° C to 120 ° C, more preferably 30 ° C.
Is in the range of -100 ° C. Examples of the compounds represented by the formulas (1) and (2) and the deuterated compounds are shown below.

[0014]

[Chemical 5]

Next, it is necessary to single crystallize the powder obtained by the reaction. Examples of the method of single crystallizing include solvent evaporation method, temperature drop method, solution method such as vapor diffusion method, Bridgman method and the like. And the sublimation method.
For single crystallization, “Crystal Engineering Handbook” edited by the Editorial Committee, “Crystal Engineering Handbook (Kyoritsu Publishing, 1971)”
This can be done by referring to the description in Chapter VII, Chapter 8. Wavelength conversion methods include a method using angular phase matching and temperature phase matching using a single crystal having an appropriate size, and a method using Cherenkov radiation using a waveguide.

An example of the latter is a fiber type optical wavelength conversion element and a light source device. In the case of the present invention, the core of the optical wavelength conversion element is represented by the formula (2). The non-linear optical material is used in a single crystal state, and the crystal orientation direction of (2) which constitutes this core is
The a-axis is set so as to extend in the major axis direction of the core, while the light source device injects a fundamental wave linearly polarized in the b-axis or c-axis direction of the crystal orthogonal to the a-axis into the light wavelength conversion element. It is characterized in that it is configured to.

Examples of the laser light source used as the fundamental wave include those shown in Table 1. The wavelength of the fundamental wave is not limited except for the influence of the absorption of the material described above. This is clear from Laser & Optronics, page 59 (published November 1987).

[0018]

[Table 1]

[0019]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. Example 1 Compound 6) was synthesized according to the following method. 23.2 g (0.17 mol) of anisaldehyde, thiazolidine-
2,4-dione 20.0 g (0.17 mol), acetic acid 9.
7 ml (0.17 mol) and 6.6 g of ammonium acetate
200 ml of acetonitrile was added to (0.17 mol) and 3
Heated to reflux for 0 minutes. After cooling, the precipitated crystals were collected by filtration,
It was dissolved in N, N-dimethylformamide. Activated carbon was added with heating and stirring at 100 ° C., and the mixture was stirred for about 5 minutes and then filtered to remove the activated carbon. Water was added to the filtrate, and the precipitated crystals were collected by filtration and washed with water and acetonitrile to obtain the compound of formula (2). Yield 22 g (55% yield), melting point 219 ° C.

The infrared absorption (IR) spectrum and nuclear magnetic resonance absorption (NMR) spectrum of the obtained compound were measured. The results are shown below. ^{_{IR (KBr) ν max cm -1}} 3225 (N-H) 3100 ( aromatic C-H) 1740,1715 (C = O) 1595 (C = C) NMR (DMSO-d 6) δppm 3.85 (S 3H, OCH ₃ ) 7.1 (d, 2H, J = 9, ortho position of OCH ₃ ) 7.55 (d, 2H, J = 9, meta position of OCH ₃ ) 7.75 (S, 1H, -CH =) 12.50 (br, 1H, NH)

Example 2 The deuterated compound 1) was obtained by the following method. 0.5 g of the compound 6) obtained in Example 1 is added to 20 ml of D
It was dissolved in MSO-d _6. While stirring this solution at room temperature, 200 ml of heavy water was added dropwise thereto over 2 hours. The precipitated crystals were collected by filtration, washed with heavy water, and dried under reduced pressure. The yield of 0.45 g and the melting point of 219 ° C. The IR and NMR spectra of the obtained crystal were measured. As a result, a remarkable decrease in absorption derived from NH was observed at 3225 cm ^{−1 in} the IR spectrum and 12.50 ppm in the NMR spectrum. It was seen. From these, it can be seen that a compound having ND was obtained.

Example 3 The compound 7) was treated in the same manner as in Example 1 with thiazolidine-
2,4-dione was replaced with 2-thioxooxazolidin-4-one to synthesize. Yield 11g (Yield 27%) Melting point 210 ° C

Example 4 Spectral absorption characteristics were examined in order to evaluate blue light transmittance. The results are shown in Table 2.

[0024]

[Table 2]

From Table 2, it can be seen that the compound of the present invention has excellent blue light transmittance. Especially, it is remarkable in the compounds 1) and 6).

Example 5 The measurement of the second harmonic generation was carried out by SK Kurt.
z), by TTPerry, Journal of Applied Physics (J.Appl.Phys.)
According to the method described in Vol. 39, page 3978 (published in 1968), the compound of the present invention was powdered. The measurement was performed using the apparatus shown in FIG. That is,
Pulse YAG laser light (λ = 1.064 μm)
, Beam diameter ≈ 1mmφ, peak power ≈ 10Mw / c
m ² ) was used as the fundamental wave, and the intensity of the second harmonic was measured by the evaluation device shown in FIG. The measurement was performed by relative comparison with the intensity of the second harmonic of urea. When the strength was weak, visual observation was performed. In particular, in order to distinguish the light emission (mainly yellow and red light emission) due to the two-photon absorption of the fundamental wave and the second harmonic, a spectroscope was inserted and only the second harmonic was measured. Furthermore, in the measurement by the powder method, it is important to judge the presence or absence of non-linearity of the substance, and since the intensity ratio is a reference value of the magnitude of non-linearity, it is not only detected by Photomal, Visual observation was also performed at the same time. The results are shown in Table 2.

[0027]

[Chemical 6]

Example 6 A single crystal was prepared by the following method. Compound 6)
Was used as an acetonitrile solution, and the solvent was gradually evaporated at room temperature. After one week, crystals of maximum 1 × 1 × 2 mm ³ were obtained. Observation with a polarization microscope revealed that the substance was a single crystal with uniform extinction. Further, when crystals were grown at 45 ° C. under reduced pressure by a method modified from the Soxhlet extraction method, almost trigonal bipyramidal crystals were obtained. The largest was about 3 mm between the top and bottom vertices, and the side length was about 5 mm.

Example 7 Among the crystals obtained by the solvent evaporation method of Example 5, the smaller one was subjected to X-ray crystal structure analysis. The results were as follows. Crystallographic data Orthorhombic system, space group Pna2 ₁ Lattice constant a = 13.151Å b = 12.213Å c = 6.468Å Number of molecules per unit lattice Z = 4 The crystal structure diagram is shown in FIG. From the space group of the crystallographic data, it can be seen that this crystal does not have inversion symmetry. In FIG. 2, A, B, and C are crystal axes a-axis, b-axis, and
The c-axis is shown.

Example 8 X-ray crystal structure analysis of the compound 7) was performed. The solvent evaporation method of the methanol solution was used for the preparation of the single crystal. The results were as follows. Crystallographic data Orthorhombic system, space group Pna2 ₁ Lattice constant a = 13.877Å b = 11.941Å c = 6.433Å Number of molecules per unit lattice Z = 4 The crystal structure diagram is shown in FIG. From the space group of the crystallographic data, it can be seen that this crystal does not have inversion symmetry. In FIG. 8, A, B, and C are crystal axes a-axis and b-axis, respectively.
An axis and a c-axis are shown.

Example 9 Among the crystals obtained by the solvent evaporation method of Example 6, a larger crystal was selected to generate the second harmonic. The apparatus of FIG. 3 was used for the experiment. FIG. 4 shows the correspondence between the crystal axis and the optical axis. X, Y, and Z represent optical axes, and a, b, and c are a axis and b.
An axis and a c-axis are shown. The YAG laser (1064 nm) polarization direction is set to 45 ° with respect to the optical axes Y and X of the crystal, and when the crystal is rotated with respect to the Z axis, green light (532 nm) is beam-shaped. I was able to observe it. This shows that the present crystal can be phase-matched at 1064 nm, and therefore the crystal of the present invention is promising as a nonlinear optical material for optical wavelength conversion.

Reference Example 1 When actually forming a fiber type optical wavelength conversion element,
It was unclear how to set the crystal orientation and the polarization direction of the fundamental wave incident on the crystal orientation to obtain high wavelength conversion efficiency. A method for setting the crystal orientation of the nonlinear optical material and the linear polarization direction of the fundamental wave suitable for obtaining high wavelength conversion efficiency will be described below. The crystals of compound 6) are orthorhombic and the point group is mm ²
Is. So the tensor of the nonlinear optical constant is Becomes Here, d ₃₁ is the crystal axis a, as shown in FIG.
Considering the optical axes X, Y, and Z defined for b and c,
Light linearly polarized in the X direction (hereinafter referred to as X polarized light. Y, Z
Is also the same. ) Is a non-linear optical constant in the case where the second harmonic of Z-polarized light is extracted by being incident as a fundamental wave, and similarly, d ₃₂ is the case where the second harmonic of Z-polarized light is extracted by injecting the fundamental wave of Y-polarized light. Non-linear optical constant, d ₃₂ is a non-linear constant when the Z-polarized fundamental wave is incident to extract the Z-polarized second harmonic, and d ₂₄ is the Y-polarized fundamental wave and the Y-polarized second harmonic is incident. Nonlinear optical constants for extracting waves,
d ₁₅ is a non-linear optical constant when the X and Z polarized fundamental waves are made incident and the X polarized second harmonic is extracted. The magnitude of each nonlinear optical constant will be described below.

Since the refractive index of the compound 6) has not been clarified yet, the nonlinear optical constant d _IJK can be derived by the following equation: d _IJK = _{Nf 1} (2ω) f _J (ω) f _K (ω) b _IJK b Indicates _IJK value. Note that N is the number of molecules per unit volume, f (ω), f
(2ω) are local electric field correction factors for the fundamental wave and the second harmonic, respectively. b ₃₁ 2.37 b ₃₂ 4.95 b ₃₃ 12.20 b ₁₅ 2.37 b ₂₄ 4.95 These b _IJK values are obtained by X-ray crystal structure analysis and PP.
It is a value based on β calculated using the P-CIMO method and the Ward's formula, and the unit is [× 10 ^-30 esu].

From this table, it can be seen that d ₃₃ , d ₃₂ , d ₂₄ and d ₁₅ can take large values. Therefore, as shown in FIG. 5, in forming the fiber type optical wavelength conversion element 101 in which the core 111 made of the compound 6) is filled in the clad 121, the crystal of the compound 6) is formed on the a-axis (X in the optical axis). (Optical axis) is oriented so as to extend in the core axial direction (this can be realized by the method described below), and the optical wavelength conversion element 101 is provided with a crystal c-axis (Z-axis in the optical axis) or b-axis. If a linearly polarized fundamental wave is made incident in the direction of (the Y axis in the optical axis), the above large nonlinear optical constant d ₂₄ ,
d ₃₂ and d ₃₃ can be used.

Reference Example 2 The value of b _IJK of compound 7) was determined in the same manner as in Reference Example 1. Record the results. The unit of b ₃₁ 4.41 b ₃₂ 6.13 b ₃₃ 17.30 b ₁₅ 4.41 b ₂₄ 6.13 is [× 10 ^-30 esu]. The same result as in the case of the compound 6) described in Reference Example 1 was obtained. Tenth Embodiment FIG. 6 shows an optical wavelength conversion module according to a tenth embodiment of the present invention. This optical wavelength conversion module is composed of a fiber type optical wavelength conversion element 101 and a light source device 20 for inputting a fundamental wave to the optical wavelength conversion element 101. Here, a method for producing the light wavelength conversion element 101 will be described. First, an aerial glass fiber to be the clad is prepared. As an example, this glass fiber is made of SFS3 glass fiber and has an outer diameter of 100.
The diameter of the hollow part is about 2 μm. On the other hand, 120 g of compound 6) in 1 liter of acetonitrile solvent
To prepare a saturated solution of compound 6) (at a temperature of 35 ° C.). A saturated solution of this compound 6) was heated to a temperature of 3 in a constant temperature bath.
Keeping the temperature constant at 5 ° C., one end of the glass fiber is introduced into this solution as shown in FIG. Then, the solution of compound 6) enters into the glass fiber due to the capillary phenomenon.
If stored in this state, the solvent acetonitrile will evaporate and become supersaturated. Then, crystal nuclei are generated inside the glass hollow tube, and a single crystal grows. As a result, a single crystal state in which the crystal orientation is uniform over a long range of 20 mm or more can be obtained.

When the compound 6) is filled in the glass fiber 129 in a single crystal state as described above, its crystal orientation state is as shown in FIG.
The shaft) extends in the axial direction of the core. After the core 111 has been filled as described above, both ends of the glass fiber 129 are cut with a fiber cutter to obtain the length 1
An optical wavelength conversion element 101 of 0 mm was formed. As shown in FIG. 6, the light wavelength conversion element 101 is combined with the light source device 20 to form a light wavelength conversion module. In this embodiment, the semiconductor laser 21 is used as a light source for generating a fundamental wave, and the wavelength 87 emitted from the semiconductor laser 21 is used.
0 nm laser light (fundamental wave) 15 is collimating lens 2
The beam is made into a parallel beam by means of 2 and then passed through the anamorphic prism pair 23 and the λ / 2 plate 25, focused into a small beam spot by the condenser lens 26, and then irradiated onto the incident end face 10a of the light wavelength conversion element 101. It As a result, the fundamental wave 15 enters the light wavelength conversion element 101. As described above, the compound 6) forming the core 111 is in a crystal orientation state in which the X axis extends in the core axis direction, while in this example, by rotating the λ / 2 plate 25 of the light source device 20, The fundamental wave 15 in the Z polarization state is input to the light wavelength conversion element 101.

The fundamental wave 15 that has entered the optical wavelength conversion element 101 is converted into the second harmonic wave 16 having a wavelength of ½ (= 435 nm) by the compound 6) that constitutes the core 111. The second harmonic 16 propagates inside the element 101 by repeating total reflection between the outer surfaces of the cladding 121, and
Phase matching is performed between the guided mode in the core part of No. 5 and the radiation mode of the second harmonic wave 16 to the cladding part (so-called Cherenkov radiation).

A beam 16 ', which is a mixture of the second harmonic wave 16 and the fundamental wave 15, is emitted from the emission end face 10b of the light wavelength conversion element 101. This outgoing beam 16 ′ is passed through a condenser lens 27 and is condensed, and then the second harmonic wave 16 of 435 nm is satisfactorily transmitted, while the fundamental wave 15 of 870 nm is passed through a band pass filter 28. Was
Only the second harmonic 16 is extracted. It was confirmed that the second harmonic wave 16 was Z-polarized light using a polarizing plate or the like. That is, in this example, the above-mentioned nonlinear optical constant d ₃₃ of (2) is used. The light intensity of the second harmonic wave 16 was measured with the optical power meter 29, and the wavelength conversion efficiency was determined to be about 1% in terms of 1 W.

[0039]

Industrial Applicability As described above, the compound of the present invention has high blue light transmittance, and the molecular crystal composed of the molecule represented by the formula (2) has no inversion symmetry in the molecular arrangement.
It has the following nonlinear optical effects. Therefore, it is a useful material for wavelength conversion using the second-order nonlinear optical effect. It is especially useful for generating converted waves in the blue region. Further, as described in detail, according to the optical wavelength conversion module of the present invention, (2)
Since the high non-linear optical constant possessed by can be actually used in the fiber type non-linear optical material and the optical wavelength conversion element can be formed sufficiently long, extremely high wavelength conversion efficiency can be realized. Moreover, since (2) has an absorption edge near 400 nm, this optical wavelength conversion module uses a laser beam of about 800 nm as a fundamental wave to efficiently extract the second harmonic in the blue region. Will also be possible.

Although the method using the Cherenkov radiation method has been described above, the present invention is not limited to these methods, and waveguide-waveguide phase matching is also possible. The wavelength-converted wave is not limited to the second harmonic, but is also used for the third harmonic, sum and difference frequency generation. It is also possible to make the above compound into a single crystal, cut out a bulk single crystal therefrom, and input YAG laser light to generate the second harmonic thereof.
Angle phase matching is used as the phase matching method at this time. These bulk single crystals can be used not only outside the cavity of the laser but also inside the cavity of a solid-state laser such as an LD pumped solid-state laser to improve the wavelength conversion efficiency. Further, the wavelength conversion efficiency can also be improved by disposing it in the resonator of the external resonator type LD. The Bridgman method, the solvent evaporation method, or the like is used for the above single crystallization. The wavelength-converted wave is not limited to the second harmonic, but is also used for generating the third harmonic and the sum / difference frequency.

[Brief description of drawings]

FIG. 1 is an apparatus for measuring second harmonic generation using powder.

FIG. 2 is a stereo view showing the crystal structure of compound 6).

FIG. 3 is an apparatus for generating a second harmonic using a single crystal.

FIG. 4 shows correspondence between a crystal axis and an optical axis.

FIG. 5 shows the crystal orientation of the core in the fiber type optical wavelength conversion element.

FIG. 6 is an explanatory view of a method for producing a fiber type optical wavelength conversion element.

FIG. 7 shows a single crystal growth apparatus by a solvent evaporation method for a fiber having a single crystal of compound 6) as a core.

FIG. 8 is a stereogram showing the crystal structure of compound 7).

[Explanation of symbols]

 1 powder sample 2 fundamental wave cut filter 3 spectroscope 4 photomal 5 amplifier 6 wavelength 1.064 μm 7 0.532 μm 10 compound 6) single crystal 11 Nd: YAG laser 13 fundamental wave cut filter 15 fundamental wave 16 second harmonic Wave 16 'Second harmonic mixed with fundamental wave 20 Light source device 21 Semiconductor laser 22 Collimating lens 23 Anamorphic prism pair 25 λ / 2 plate 26, 27 Focusing lens 28 Bandpass filter 29 Optical power meter 128 Compound 6) Saturated solution 129 Clad (glass fiber) 101 Optical wavelength conversion element 111 Core 121 Clad a Crystal axis a b Crystal axis b c Crystal axis c 10a Incident end face 10b Emitting end face

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keizo Ogawa 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture, Fuji Photo Film Co., Ltd. (72) Akinori Harada, Inventor 798 Miyadai, Kaisei-cho, Ashigarakami-gun, Kanagawa Fuji Photo Film Co., Ltd.

Claims (4)

[Claims] 1. A compound represented by the following formula (1) and a compound in which at least one hydrogen atom is replaced by a deuterium atom. Formula (1) In the formula, R represents an alkyl group. 2. An orthorhombic system comprising a molecule represented by the following formula (2): Pna2 ₁
Crystal with a space group of Formula (2) In the formula, X and Y each represent a sulfur atom or an oxygen atom. However, X and Y are not the same. 3. A method of converting a light wavelength using a single crystal composed of a molecular crystal according to claim 2 as a nonlinear optical material when converting a light wavelength using a laser beam and a nonlinear optical material. 4. A single-crystal nonlinear optical material characterized by being constituted by a molecule represented by the formula (2) is filled in the clad as a core, and the a-axis of the crystal of the optical material is substantially the core axis. A light wavelength conversion element that is oriented so as to extend in a direction, and a light source device that causes a linearly polarized fundamental wave to enter the light wavelength conversion element in the direction of the b axis or c axis of the crystal orthogonal to the a axis. Optical wavelength conversion module. (However, the method of determining the crystal axis is based on the 2-fold axis as the C axis, and the other crystal axes follow the right-handed system.)