JPH06337452A - Non-linear optical material and short wavelength laser oscillator using the same - Google Patents

Abstract

PURPOSE:To provide a non-linear optical material made of a crystal which has a sufficient dimension and hardness to work to a crystal for a device, has high efficiency of optical wavelength transmission caused by second higher harmonic wave generation, has a light absorption end existing in the short wavelength, and has almost no absorption in the region of blue color which is a second higher harmonic wave of a semiconductor laser. CONSTITUTION:A non-linear optical material made of a dipotassium 4, 4'- oxodiphenoxide crystal is obtained by neutralization reaction. The crystal obtained is suitably sticked with quartz glass with nonreflective coating through matching oil or a resin to obtain a light wavelength changing device 4. This device is inserted into a photoresonator 6 composed with the edge of fundmental wave oscillator crystal 3 and the surface of a mirror 5 to make a short wavelength laser oscillator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonlinear optical material having a second-order nonlinear optical characteristic and a short wavelength laser oscillator using the nonlinear optical material.

[0002]

2. Description of the Related Art In recent years, active research and development have been conducted on organic crystals having a large quadratic nonlinear optical constant as compared with conventional inorganic nonlinear optical materials. These organic crystals are roughly classified into molecular crystals and ionic crystals such as salts. Examples of compounds that form ionic crystals include trans-4′-dimethylamino-N-methyl-
4-Stilbazolium-methylsulfate (ACS Symposium Series 233 (1983) 109 (ACS Symp. Se
r.233 (1983) 109)), L-arginine phosphate monohydrate (abbreviation LAP), deuterated LAP (abbreviation D).
LAP) (Journal of Japan Society for Crystal Growth 16 (1989) 34-41)
Page) is known.

[0003]

However, the above-mentioned conventional method 2
Regarding the organic crystal having the following nonlinear optical characteristics, in the case of a molecular crystal, the molecules are bound to each other by Van der Waals force, hydrogen bond, etc. in the crystal, and the symmetry of the molecule is poor, so the cohesive force is weak, There is a problem that it is generally difficult to obtain a crystal having a size and hardness sufficient for processing into a device crystal. In addition, since the crystal is generally soft, heat conduction in the crystal is poor, and when used for optical wavelength conversion by generating the second harmonic, a large temperature gradient is generated in the crystal, and the phase matching of the fundamental wave and the second harmonic is generated. There was a problem that the conditions changed significantly and high conversion efficiency could not be obtained.

On the other hand, in the case of an ionic crystal such as a salt, an electrostatic attractive force, which is a stronger cohesive force than a Van der Waals force or a hydrogen bond, is generated in the crystal. It can be obtained relatively easily.

However, even in the conventionally known organic ionic crystal having a second-order nonlinear optical characteristic, there is a problem in wavelength conversion by generation of the second harmonic of laser light, as shown below.

First, in trans-4'-dimethylamino-N-methyl-4-stilbazolium-methylsulfate crystal, the compound has a very long π-electron conjugation length, so that the maximum absorption wavelength of light is Nd: YAG laser light or Since the wavelength is about the same as the second harmonic of the semiconductor laser light, there is a problem that the wavelength-converted light is absorbed by the material and the wavelength cannot be efficiently converted.

In addition, LAP crystals and DLAP crystals have small second-order nonlinear optical constants.
Therefore, there is a problem that the conversion efficiency of low power laser light is particularly small and it cannot be used for wavelength conversion of semiconductor laser light.

The present invention solves the above-mentioned problems of the prior art, has a size and hardness sufficient for processing into a device crystal, is excellent in light wavelength conversion characteristics due to generation of second harmonics, and is a semiconductor laser light or the like. Has a good conversion efficiency for low power laser light, has an absorption edge at a short wavelength, and has almost no absorption in the blue region, which is the second harmonic of the semiconductor laser, and a nonlinear optical material made of such a crystal. It is an object of the present invention to provide a short-wavelength laser oscillating device having excellent oscillating light intensity characteristics used for an element.

[0009]

To achieve the above object, the non-linear optical material of the present invention is provided with an anion and a metal cation formed by the loss of a proton from at least one hydroxyl group of 4,4'-dihydroxybenzophenone. It is provided with a structure that it is composed of crystals containing a salt composed of ions.

In the above structure, the metal is preferably selected from alkali metals and alkaline earth metals. Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium and the like. Examples of the alkaline earth metal include beryllium, magnesium, calcium, strontium, and bium.

In the above, when the metal is an alkali metal, it is preferably at least one selected from potassium, sodium and lithium. Further, in the above-mentioned constitution, it is preferable that it is composed of a salt in which hydrogen of two hydroxyl groups of 4,4′-dihydroxybenzophenone is replaced by potassium (dipotassium 4,4′-oxodiphenoxide), and a crystal containing water of crystallization. .

In the above constitution, a salt in which hydrogen of two hydroxyl groups of 4,4'-dihydroxybenzophenone is replaced by potassium (dipotassium 4,4'-oxodiphenoxide), and a hydrogen atom is replaced by a deuterium atom. It is preferably composed of crystals containing water of crystallization.

Next, the short wavelength laser oscillator of the present invention is
What is claimed is: 1. A laser oscillation device comprising at least a semiconductor laser, an optical resonator, and an optical wavelength conversion element existing in the optical resonator, wherein the optical wavelength conversion element is made of any one of the above-mentioned nonlinear optical materials. It is characterized by being.

[0014]

According to the structure of the present invention, since the non-linear optical material is a salt, it is possible to easily obtain a crystal having a hardness sufficient for processing into a device crystal. The anion formed by removing a proton from at least one hydroxyl group of 4,4′-dihydroxybenzophenone is a phenylene group having an electron donating group having an appropriate electron donating ability bonded to the p-position, It has a structure in which it is bonded via a carbonyl group, which is an electron-accepting group having acceptability, and can simultaneously realize a large molecular hyperpolarizability β and a shorter wavelength absorption edge for light. Further, since the alkali metal cations and / or the alkaline earth metal cations also hardly absorb light in the visible light wavelength region, the wavelength of the light absorption edge can be shortened in the nonlinear optical material of the present invention. Furthermore, since the crystal is hard and the heat conduction in the crystal is good, the temperature gradient generated in the crystal is small when used for optical wavelength conversion by generating the second harmonic, and the phase of the fundamental wave and the second harmonic is small. The fluctuation of the matching condition becomes smaller, and high conversion efficiency can be obtained.

As described above, according to the present invention, it has a sufficient size and hardness to be processed into a device crystal, and
It has excellent optical wavelength conversion characteristics due to the generation of harmonics, has good conversion efficiency for low-power laser light such as semiconductor laser light, and has an absorption edge at a short wavelength (that is, in the blue region that is the second harmonic of the semiconductor laser). It is possible to obtain a non-linear optical material composed of excellent crystals (without absorption).

Further, according to the preferable constitution of the present invention in which the metal is alkaline metal, the alkali metal is more positive than the alkaline earth metal, and it is easier to form an ionic crystal, so that the non-linear material can be produced more easily. You can

Further, among the constitutions in which the metal is an alkali metal, according to the preferable constitution of the present invention in which the alkali metal is potassium, potassium is naturally present in a relatively large amount and the raw material can be easily obtained at a low cost. In addition to being able to obtain the above-mentioned nonlinear optical material, potassium has a relatively small atomic volume among alkali metals, so that in the crystal of the nonlinear optical material, a large supramolecular polarizability β that contributes to the second harmonic generation characteristic is obtained. The volume ratio of the anions to the whole becomes large, and the light wavelength conversion characteristic by generation of the second harmonic, which is more excellent as a crystal, is realized.

Further, among the constitutions in which the metal is an alkali metal, according to the preferable constitution of the present invention in which the alkali metal is sodium, sodium is naturally present in a relatively large amount and the raw material can be easily obtained at low cost. In addition to being able to obtain the above-mentioned nonlinear optical material, sodium has the second smallest atomic volume next to lithium among alkali metals.
The volume ratio of the anion having the large supramolecular polarizability β contributing to the harmonic generation characteristic to the whole is large, and the light wavelength conversion characteristic by the second harmonic generation, which is more excellent as a crystal, is realized.

Further, according to the preferable constitution of the present invention in which the alkali metal is lithium among the constitutions in which the metal is the alkali metal, lithium has the smallest atomic volume among the alkali metals. In the crystal, the volume ratio of the anion having a large supramolecular polarizability β that contributes to the second harmonic generation characteristic becomes large, and the light wavelength conversion characteristic by the second harmonic generation that is very excellent as a crystal is realized. To be done.

Further, in the constitution in which the metal is an alkali metal, a salt obtained by substituting hydrogen for two hydroxyl groups of 4,4'-dihydroxybenzophenone with potassium (dipotassium 4,4'-oxodiphenoxide). According to a preferred structure of the present invention, which comprises a crystal containing water and water of crystallization, the crystal structure is different from that in the case where one hydroxyl group is ionized because two hydroxyl groups of 4,4′-dihydroxybenzophenone are ionized. The electrostatic attraction that works inside becomes larger and the cohesive force also becomes larger. In addition, since it contains water of crystallization, it is considered that hydrogen bonding develops in the crystal and the cohesive force acting in the crystal becomes even greater.
It is considered that the hardness of the crystal becomes larger and the heat conduction in the crystal also becomes larger.

Therefore, a non-linear optical material consisting of a crystal containing a salt (dipotassium 4,4'-oxodiphenoxide) obtained by substituting hydrogen for two hydroxyl groups of 4,4'-dihydroxybenzophenone with potassium and crystal water. According to this, a non-linear optical material having higher hardness, easier to process into a device crystal, and more excellent in light wavelength conversion characteristics can be obtained. Further, since water of crystallization has almost no light absorption in the visible light wavelength region, the light absorption edge of the crystal can be shortened.

Further, a salt (dipotassium 4,4'-oxodiphenoxide) obtained by substituting hydrogen in two hydroxyl groups of 4,4'-dihydroxybenzophenone with potassium and a crystal in which a hydrogen atom is replaced by a deuterium atom According to the preferred constitution of the present invention, which comprises a crystal containing water, the two hydroxyl groups of 4,4'-dihydroxybenzophenone are ionized, so that in the crystal compared to the case where one hydroxyl group is ionized. The electromotive force that works becomes larger and the cohesive force also becomes larger.
In addition, since the hydrogen atom contains water of crystallization in which isotope deuterium atom is substituted, it is considered that a hydrogen bond-like bond develops in the crystal and the cohesive force acting in the crystal further increases.

Further, a crystal obtained by substituting hydrogen for two hydroxyl groups of 4,4'-dihydroxybenzophenone with potassium (dipotassium 4,4'-oxodiphenoxide) and crystal water is a molecule of crystal water. Since a harmonic component of light absorption due to vibration slightly appears near the wavelength of 1064 nm, the efficiency of wavelength conversion due to generation of the second harmonic of a fundamental wave having a wavelength near this wavelength, for example, Nd: YAG laser is reduced. On the other hand, a salt (dipotassium 4,4′-oxodiphenoxide) obtained by substituting hydrogen for two hydroxyl groups of 4,4′-dihydroxybenzophenone with potassium and crystal water in which a hydrogen atom is substituted with a deuterium atom are used. In the containing crystal, the state of molecular vibration of crystal water changes and light absorption hardly appears near the wavelength of 1064 nm. A fundamental wave with a wavelength near the wavelength,
For example, the efficiency of wavelength conversion due to the generation of the second harmonic of the Nd: YAG laser hardly decreases. Therefore,
From a crystal containing a salt (dipotassium 4,4'-oxodiphenoxide) obtained by substituting hydrogen for two hydroxyl groups of 4,4'-dihydroxybenzophenone with potassium and water of crystallization in which a hydrogen atom is replaced by a deuterium atom. According to the non-linear optical material, which has a greater hardness,
It is possible to obtain a non-linear optical material that is easier to process into a crystal for an element, has better optical wavelength conversion characteristics, and particularly has a higher optical wavelength conversion efficiency due to the generation of the second harmonic of the fundamental wave having a wavelength near 1064 nm. it can.

Next, according to the constitution of the short-wavelength laser oscillator of the present invention, all of the above-mentioned nonlinear optical materials have excellent light wavelength conversion characteristics as described above and, at the same time, Nd: Y.
Regarding wavelength conversion of AG laser and semiconductor laser,
High oscillating light intensity is realized because it has a sufficiently high transmittance for the fundamental wave and harmonics and has excellent processing characteristics (a crystal for an element with less disordered optical characteristics can be obtained).

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples. The nonlinear optical material that can be used in the present invention contains a salt, and the salt has, for example, a structural formula represented by the following formulas (Formulas 1 to 4).

[0026]

[Chemical 1]

[0027]

[Chemical 2]

[0028]

[Chemical 3]

[0029]

[Chemical 4]

In the above formulas (Formula 1 and 2), M represents an alkali metal such as lithium, sodium, potassium, rubidium and cesium, and N represents an alkaline earth metal such as beryllium, magnesium, calcium, strontium and bium. Show. As a special example, N may be a cation such as manganese. In addition to the salt, the non-linear engineering material that can be used in the present invention may contain, for example, water of crystallization or water of crystallization in which hydrogen atoms are replaced by deuterium atoms.

Example 1 15 ml of water was added to 2.14 g of commercially available 4,4'-dihydroxybenzophenone (content of 98.0% or more), and 2.24 g of commercially available potassium hydroxide was dissolved in 10 ml of water to prepare the solution. When the aqueous solution was added dropwise at room temperature, it became a yellow solution. ph value is 10 to 11
Met. This solution was filtered, transferred to a beaker, covered with a commercially available cellulose wiper, and allowed to stand at room temperature to gradually evaporate water. As a result, pale yellow crystals with relatively excellent transparency were formed in about 21 days. Was obtained. This was dried and used as a sample.

Of a sample of dimethylsulfoxide-d6 solution
^{The 1} H-NMR spectrum (internal standard: tetramethylsilane) was based on the hydrogen atom bonded to the benzene ring of the 4,4′-oxodiphenoxide anion for the sample.
Individual signals were observed at 6.45 ppm and 7.38 ppm (integrated intensity ratio was 1: 1), and a very broad signal based on water molecules was observed at around 4.5 ppm. No other signal such as a signal based on the hydroxyl group bonded to the benzene ring was observed. ¹³ C-NM of the solution
In the R spectrum, for the sample, the signal based on the carbon atom of the benzene ring of the anion was 116.1 pp.
m, 123.7 ppm, 131.7 ppm and 169.
Four were observed at 0 ppm, and a signal based on the carbon of the carbonyl group of the anion was observed at 191.6 ppm. From these results, it is considered that the sample contains symmetrically shaped dipotassium 4,4′-oxodiphenoxide and water.

The sample was thermogravimetrically analyzed in a nitrogen atmosphere at a temperature rising rate of 10 ° C./min.
The first-stage weight loss of the above occurred, and the second-stage weight loss (7.2% weight loss in the first and second stages) occurred from 121 ° C to 156 ° C. In addition, according to the differential scanning calorimetry (temperature rising (cooling) rate: 5 ° C./min, under nitrogen atmosphere) of the sample, when the sample was cooled from 30 ° C. to −50 ° C.
When heated from 50 ° C., almost no heat input or output due to freezing of water (melting of ice) was observed.

From these results, it is considered that the sample contains 7.2% of water, and a considerable part thereof is crystal water. The second harmonic generation (SHG) efficiency was measured on the sample by the powder method according to the Kurtz method described in Journal of Applied Physics 39 (1968), page 3798. The sample was powdered in an agate mortar and used, and an Nd: YAG laser (wavelength 1064 nm) was used as a light source.
The SHG efficiency was about 5 times that of urea, and excellent second harmonic generation characteristics were observed. The SHG efficiency of the raw materials 4,4′-dihydroxybenzophenone and potassium hydroxide was below the measurement limit.

Example 2 Commercially available 4,4'-dihydroxybenzophenone (content 9
15 ml of water was added to 2.14 g (8.0% or more), and commercially available sodium hydroxide (content 97.0% or more) 0.8
An aqueous solution prepared by dissolving 92 g in 10 ml of water was added dropwise at room temperature to give a yellow solution. ph value is 10
It was from 11 to 11. The solution was filtered, transferred to a beaker, covered with a commercially available cellulose wiper, and allowed to stand at room temperature to evaporate water gradually. As a result, a pale yellow precipitate was obtained in about 23 days. This was dried and used as a sample. When the SHG efficiency of this sample was measured by the same method as in Example 1, it was about the value of urea, and an excellent second harmonic generation characteristic was observed. The SHG efficiency of the raw materials 4,4′-dihydroxybenzophenone and sodium hydroxide was below the measurement limit.

Example 3 Commercially available 4,4'-dihydroxybenzophenone (content 9
(8.0% or more) 2.14 g of water was added to 10 ml of water, and 0.839 g of commercially available lithium hydroxide monohydrate was added to 10 m of water.
When an aqueous solution prepared by dissolving in 1 was added dropwise at room temperature, it became a deep yellow solution. The ph value was 9 to 10. The solution was filtered, transferred to a beaker, covered with a commercially available cellulose wiper, and allowed to stand at room temperature to evaporate water gradually. As a result, a yellow precipitate was obtained in about 20 days. This was dried and used as a sample. When the SHG efficiency of this sample was measured by the same method as in Example 1, it was about the value of urea, and excellent second harmonic generation characteristics were observed. Regarding the raw material 4,4′-dihydroxybenzophenone and lithium hydroxide monohydrate, SH
The G efficiency was below the measurement limit.

Example 4 Crystals of dipotassium 4,4'-oxodiphenoxide were grown in the same manner as in Example 1. Large crystals, for example 7 mm × 6 mm × 4 mm, were obtained in about 20 days. This crystal was designated as Sample 1. The light absorption edge wavelength of Sample 1 was about 420 nm as a result of measurement by a transmission method using a spectrophotometer.

Example 5 Instead of the water used in Example 1, heavy water (99.9% atom D) was used to grow crystals of dipotassium 4,4'-oxodiphenoxide in the same manner. Large crystals, eg 9 mm × 7 mm × 5 mm, were obtained in about 20 days. This crystal was designated as Sample 2. The light absorption edge wavelength of Sample 2 was about 420 nm as a result of measurement by a transmission method using a spectrophotometer.
Met.

Although the crystal growth in this embodiment was performed by the solvent evaporation method, the temperature drop method may be used. The solvent evaporation method for performing crystal growth, an ordinary method is used for the temperature drop method, and is not particularly limited, but, for example, the solvent evaporation method is a saturated solution in which a component that normally becomes a crystal is dissolved in an appropriate solvent. It is a method of gradually evaporating a solvent using a solution to precipitate and grow a target crystal.

Embodiment 6 A short wavelength laser oscillator according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of the configuration of a short-wavelength laser oscillation device. 1 is a semiconductor laser, 2 is a lens system for condensing a semiconductor laser, 3 is a crystal for fundamental wave oscillation, 4 is an optical wavelength conversion element, 5 is a mirror ( (In this example, a concave mirror), 6 is an optical resonator,
Reference numeral 7 indicates output light. In this embodiment, in the optical resonator 6 constituted by the end face of the crystal 3 for fundamental wave oscillation and the face of the mirror 5,
The light wavelength conversion element 4 (thickness 1 to 5 mm) is inserted.
The surface of the mirror 5 reflects the light of the wavelength of the fundamental wave oscillated by exciting the crystal for oscillating the fundamental wave, but the light of the wavelength of the second harmonic generated by wavelength conversion by the light wavelength conversion element 4 Is formed with a dielectric multi-layered film that is transparent, and the end face of the laser oscillation crystal 3 (lens system 2
On the side surface), a dielectric multilayer film is formed which can transmit light having a wavelength emitted from one semiconductor laser but reflect light having a fundamental wavelength and light having a second harmonic wavelength. .

The optical wavelength conversion element 4 is made of quartz glass coated with a non-reflective coating so as to easily transmit the light of the fundamental wave wavelength and the second harmonic wave to the surface thereof through the matching oil or the resin. It is attached to a wave generating crystal. When a resin is used, for example, an epoxy resin having a refractive index close to that of the second harmonic generation crystal is used. The second harmonic generation crystal is used for optical wavelength conversion (second
Any of the nonlinear optical materials of the present invention cut out under the condition that phase matching occurs in the generation of harmonics.

The laser light oscillated using the semiconductor laser 1 is condensed by the lens system 2 and the crystal 3 for oscillating the fundamental wave is generated.
To oscillate the fundamental wave oscillating crystal 3 to oscillate a laser beam serving as a fundamental wave. A part of the fundamental wave is wavelength-converted by passing through the optical wavelength conversion element 4, and the second wavelength is converted into the second wavelength.
Generate harmonics. These laser lights reach the mirror 5, and the fundamental wave whose wavelength has not been converted is reflected here,
The wavelength-converted second harmonic wave passes through the mirror 5. The fundamental wave reflected by the mirror 5 passes through the optical wavelength conversion element 4 again, and a part of the fundamental wave is wavelength-converted to generate a second harmonic. These laser lights are reflected by the end surface (surface on the lens system 2 side) of the fundamental wave oscillating crystal 3 and pass through the light wavelength conversion element. Such steps are repeated, the fundamental wave passes through the optical wavelength conversion element 4 many times, and the wavelength-converted second harmonic is output as the output light 7.

In the short-wavelength laser oscillator of the present invention as described above, wavelength conversion is performed by using a very strong electric field intensity in the optical resonator 6 as a fundamental wave, so that large wavelength conversion efficiency and oscillation intensity are expected. It

If there is a material that can directly coat the organic crystal with antireflection, it may be used. The semiconductor laser 1 has a wavelength of 808 nm, a power of 1 W, and a crystal 3 for fundamental wave oscillation.
Is a Nd: YAG crystal with laser light having a wavelength of 1064 nm as a fundamental wave, a crystal for second harmonic generation is cut out from sample 1, and quartz glass coated with an antireflection coating is attached through a matching oil to have a thickness of 3 mm. When the optical wavelength conversion element 4 of No. 2 was used, a large output light of 0.2 mW was obtained.

The semiconductor laser 1 has a wavelength of 808 nm and a power of 1 W, the laser oscillating crystal 3 is an Nd: YAG crystal, and the laser light having a wavelength of 1064 nm is used as the fundamental wave. The second harmonic generating crystal is cut out from the sample 2 and matched. When quartz glass coated with an anti-reflection coating through oil is pasted to form a light wavelength conversion element 4 having a thickness of 3 mm, 2 m
Output light with a large output of W was obtained.

[0046]

According to the non-linear optical material of the present invention, it has sufficient hardness to be processed into a device crystal, has an excellent wavelength conversion characteristic due to the generation of the second harmonic, and has a low power of semiconductor laser light or the like. It is possible to provide an excellent non-linear optical material made of a crystal which has a good conversion efficiency of laser light and has an absorption edge at a short wavelength (that is, almost no absorption in the blue region which is the second harmonic of a semiconductor laser).

Next, according to the short-wavelength laser oscillating device of the present invention, the non-linear optical material has an excellent optical wavelength conversion characteristic and also has a sufficiently high transmittance for the fundamental wave and the higher harmonic wave, and is excellent in the processing characteristics. Since a device crystal with less disordered characteristics can be obtained), a large oscillation light intensity can be realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a configuration of a short wavelength laser oscillator according to an embodiment of the present invention.

[Explanation of symbols]

 1 Semiconductor Laser 2 Lens System for Focusing Semiconductor Laser 3 Crystal for Fundamental Wave Oscillation 4 Optical Wavelength Converter 5 Mirror 6 Optical Resonator 7 Optical Output

Claims (6)

[Claims] 1. A nonlinear optical material comprising a crystal containing a salt of an anion formed by loss of a proton from at least one hydroxyl group of 4,4′-dihydroxybenzophenone and a metal cation. 2. The nonlinear optical material according to claim 1, wherein the metal is selected from alkali metals and alkaline earth metals. 3. The nonlinear optical material according to claim 2, wherein the alkali metal is at least one selected from potassium, sodium and lithium. 4. The nonlinear optical material according to claim 2, which comprises a salt in which hydrogen of two hydroxyl groups of 4,4′-dihydroxybenzophenone is replaced by potassium, and a crystal containing water of crystallization. 5. The salt according to claim 2, which comprises a salt in which hydrogen of two hydroxyl groups of 4,4′-dihydroxybenzophenone is replaced by potassium, and a crystal containing water of crystallization in which hydrogen atom is replaced by deuterium atom. Non-linear optical material. 6. A short wavelength laser oscillating device comprising at least a semiconductor laser, an optical resonator, and an optical wavelength conversion element existing in the optical resonator, wherein the optical wavelength conversion element comprises: A short-wavelength laser oscillating device comprising the nonlinear optical material according to any one of claims 1 to 5.