Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/35—Non-linear optics
  • G02F1/3501—Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/35—Non-linear optics
  • G02F1/3501—Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
  • G02F1/3505—Coatings; Housings; Supports

Definitions

• Wavelength conversion method Wavelength conversion method, wavelength conversion device, and laser processing machine
• the present invention relates to a wavelength conversion technology using a nonlinear optical crystal.
• FIG. 12 is a cross-sectional view showing a conventional wavelength converter disclosed in, for example, Japanese Patent Application Laid-Open No. 11-271820.
• 1 denotes a vacuum vessel, '2 for example cesium-lithium ⁇ volley Bok (chemical formula: C s L i B s O 10, abbreviated: CLB 0) nonlinear optical crystal of a crystal such as, 3 a, 3 b Is an optical window, 4a, 4b, and 4c are O-rings, 5 is a vacuum sealing valve, and 6 is a fixture.
• ⁇ indicates the entire wavelength converter.
• the laser beam enters the vacuum vessel 1 from the input side optical window 3a, interacts with the nonlinear optical crystal 2, undergoes wavelength conversion, and then exits from the output side optical window 3b.
• a vacuum sealing valve 5 is provided on the upper portion of the vacuum vessel 1 .O-rings 4 a, 4 b, and 4 are provided between the main body of the vacuum vessel 1 and the optical windows 3 a, 3 b and the vacuum sealing valve 5. 4c, and the inside of the vacuum vessel 1 is maintained at a vacuum.
• the nonlinear optical crystal 2 is pressed from above by a fixture 6 and is fixed to the bottom of the vacuum vessel 1.
• Nonlinear optical crystal 2 wavelength Since the conversion crystal adheres to the optical window, a wavelength-converted laser beam (that is, light whose wavelength has been converted by the nonlinear optical crystal) cannot be generated stably for a long period of time, and the container needs to be a vacuum container.
• a wavelength-converted laser beam that is, light whose wavelength has been converted by the nonlinear optical crystal
• the present invention has been made in order to solve the above-described problems, and a wavelength conversion method and a wavelength conversion apparatus capable of stably generating light whose wavelength has been converted by a nonlinear optical crystal for a long period of time, and It is an object of the present invention to provide a wavelength conversion laser device and a laser processing machine using the same.
• the wavelength conversion method according to the present invention is the wavelength conversion method of passing light through a nonlinear optical crystal to convert the wavelength, wherein the atmosphere in contact with the emission end face of the nonlinear optical crystal where the wavelength-converted light is emitted includes a nitrogen element content. Is to convert the wavelength into a gas smaller than air.
• the wavelength conversion is performed by covering the incident end face of the nonlinear optical crystal on which the wavelength-converted light is incident and the emission end face from which the wavelength-converted light is emitted with a gas having a nitrogen element content smaller than that of air. According to this, it is possible to obtain the effect that the light whose wavelength has been converted by the nonlinear optical crystal can be generated more reliably and stably for a long period of time.
• a gas having a nitrogen element content lower than that of air is supplied to at least the vicinity of the emission end face of the nonlinear optical crystal and then discharged. According to this, even if impurities are generated, fresh gas is supplied to the vicinity of the nonlinear optical crystal, so that the impurities can be more reliably prevented from adhering to the nonlinear optical crystal. Is obtained.
• the gas having a nitrogen content lower than that of air is a gas having a volume content of a gas containing nitrogen element of 10% or less. According to this, it is possible to obtain an effect that light whose wavelength has been converted by the nonlinear optical crystal can be stably generated for a long period with a simple configuration.
• the nonlinear optical crystal is a crystal containing cesium. According to this, it is possible to obtain an effect that high-output light in the ultraviolet region converted in wavelength by the nonlinear optical crystal can be generated stably for a long time.
• the gas is a rare gas, an oxygen gas, or a carbon dioxide gas. It is a gas mainly composed of any of the above.
• a wavelength conversion device is a wavelength conversion device for converting light by passing light through a nonlinear optical crystal, wherein an atmosphere in contact with a surface of the nonlinear optical crystal in which the wavelength-converted light is emitted has a nitrogen element content. It is equipped with means for making the body smaller than air.
• the high-power light whose wavelength has been converted by the nonlinear optical crystal is
• a means for circulating a gas with a nitrogen content lower than that of air It is provided. According to this, even if impurities are generated, they are exhausted together with the flowing gas, so that the effect of preventing the impurities from adhering to the nonlinear optical crystal or the optical window can be obtained.
• a nonlinear optical crystal is disposed in a container partially provided with a window or an opening through which incident light and output light pass, and a gas having a nitrogen element content lower than that of air is supplied to the nonlinear optical crystal in the container. It is provided with means for supplying at least in the vicinity of the emission end face, and means for discharging the supplied gas from the container.
• the gas having a nitrogen content lower than that of air is a gas having a volume content of a gas containing nitrogen element of 10% or less. According to this, it is possible to obtain an effect that light whose wavelength has been converted by the nonlinear optical crystal can be stably generated for a long period with a simple configuration. Further, the nonlinear optical crystal is a crystal containing cesium. According to this, it is possible to obtain an effect that high-output light in the ultraviolet region, wavelength-converted by the nonlinear optical crystal, can be generated stably for a long period of time.
• the gas having a nitrogen element content lower than that of air is a gas mainly composed of a rare gas, oxygen gas, or carbon dioxide gas. According to this, it is possible to obtain an effect that light whose wavelength has been converted by the nonlinear optical crystal can be stably generated for a long period with a simpler configuration.
• a gas having a nitrogen element content smaller than that of air, which is an atmosphere in contact with a surface of the nonlinear optical crystal from which light is emitted is mainly composed of argon gas. Is the body.
• a laser processing machine includes a processing machine, and includes, as a processing light source, a laser device serving as a light source for wavelength conversion, and an atmosphere in contact with a surface of the nonlinear optical crystal from which the wavelength-converted light is emitted, containing a nitrogen element.
• a wavelength conversion device that includes means for converting the laser light from the laser device through the nonlinear optical crystal to a wavelength conversion device.
• FIG. 1 is a longitudinal sectional view of a wavelength converter according to Embodiment 1 of the present invention
• FIG. 2 is a longitudinal sectional view of a wavelength converter according to Embodiment 1 of the present invention
• FIG. 3 is according to Embodiment 2 of the present invention
• FIG. 4 is a longitudinal sectional view of a wavelength converter according to Embodiment 2 of the present invention
• FIG. 5 is a longitudinal sectional view of a wavelength converter according to Embodiment 3 of the present invention
• FIG. FIG. 7 is a longitudinal sectional view of a wavelength converter according to Embodiment 4 of the present invention
• FIG. 7 is a longitudinal sectional view of a wavelength converter according to Embodiment 5 of the present invention
• FIG. 8 is a wavelength converter according to Embodiment 6 of the present invention.
• FIG. 9 is a longitudinal sectional view of a wavelength conversion device according to Embodiment 7 of the present invention
• FIG. 10 is a longitudinal sectional view of a wavelength conversion laser device according to Embodiment 8 of the present invention
• FIG. FIG. 12 is a longitudinal sectional view of a laser beam machine according to a ninth embodiment of the present invention
• FIG. 12 is a longitudinal sectional view of a conventional wavelength converter.
• the present inventors investigated the cause of deterioration of wavelength conversion characteristics using a CLBO crystal by using the second harmonic of a neodymium-Yag (Nd: YAG) laser with a wavelength of 1064 nm, that is, a laser beam with a wavelength of 532 nm.
• a laser device that generates light as a light source an ultraviolet laser beam with a wavelength of 266 nm, which is the fourth harmonic of an Nd: YAG laser, was continuously generated for 100 hours using a CLBO crystal.
• the CLBO crystal was placed on air in air and used at a constant temperature of 140 ° C.
• the average power of the generated 266 nm ultraviolet laser beam was 20 W.
• newly attached substances were observed on the UV laser beam output end face of the CLBO crystal, ie, the face from which the wavelength-converted light was emitted. Consequently having conducted the elemental analysis and structural analysis of materials, deposited substance was found to be nitric acid compounds containing nitrate Seshiumu (C s N 0 3). This cesium nitrate is observed only at the UV laser beam emission end face of the CLBO crystal, and cesium is an element not contained in components other than the CLBO crystal used for wavelength conversion.
• the atmosphere in contact with at least the emission end face of the shaped optical crystal from which the wavelength-converted light is emitted is set to be a gas having a lower nitrogen element content than air, and desirably contains almost no nitrogen element (N) It was clarified that high-output wavelength conversion could be performed more stably for a longer period of time if converted to gas when compared to air.
• FIG. 1 and 2 are diagrams for explaining a wavelength conversion method and a wavelength conversion device according to a first embodiment for carrying out the present invention. More specifically, FIG. FIG. 2 is a cross-sectional view of the wavelength converter.
• reference numeral 2 denotes a nonlinear optical crystal.
• 3a and 3b are optical windows for transmitting the laser beam.
• 4a and 4b are 0 rings.
• Reference numeral 1 denotes a container for storing the nonlinear optical crystal 2.
• 12a and 12b are optical window holders.
• 13 a and 13 b are holes made in the container 11.
• 14a and 14b are stoppers.
• 15a and 15b are pipes.
• 16 is a gas that contains no nitrogen element (N) or contains little nitrogen element.
• 17a and 17b are fixing jigs for fixing the nonlinear optical crystal 2 to the container 11.
• 7a shows the entire wavelength converter.
• the nonlinear optical crystal 2 is cut and polished at both ends to a phase matching angle for generating an ultraviolet laser beam with a wavelength of 40 Onm or less by wavelength conversion, and fixed on the container 11 by fixing jigs 17a and 17b. Is done.
• the nonlinear optical crystal 2 is made of a CLBO crystal, and both end faces are cut and polished at a phase matching angle for converting a laser beam having a wavelength of 532 nm into an ultraviolet laser beam having a wavelength of 266 nm.
• the optical windows 3a and 3b have a wavelength of at least 200 ⁇ ! Clear, for example, quartz against Leh Zabimu of ⁇ 1500 nm (Formula: S i 0 2), 'fluoride Karushiu Beam (Formula: CaF 2) consist etc., are polished end surfaces in close contact with the container 11 by 0-ring 4 a, 4 via the b optical window retainer 12 a, 12 b.
• the plugs 14a and 14b used here are directly joined to the container 11 by PT screws (tapered screws for pipes).
• the container 11 is kept airtight by the optical windows 3a, 3b and the O-rings 4a, 413 and the stoppers 14 &, 14b.
• the laser beam enters the container 11 from the input side optical window 3a, is converted in wavelength by the nonlinear optical crystal 2, and then exits from the output side optical window 3b.
• Gas 16 does not contain nitrogen element (N) to the component, or a gaseous nitrogen element is not small, for example a rare gas, oxygen gas (0 2), carbon dioxide (co 2) the use of a gas mainly containing such And flows into the container 11 through the pipe 15a and the perforated plug 14a, and flows out of the container 11 through the perforated plug 14b and the pipe 15b. . For this reason, the inside of the container 11 is filled with a gas 16 which does not contain nitrogen element or has a low nitrogen element.
• N nitrogen element
• the wavelength conversion device 7a is configured as described above, and the incident end face of the nonlinear optical crystal 2 where the wavelength-converted light is incident and the emission end face where the wavelength-converted light exits are: Since it is exposed to a gas 16 that does not contain nitrogen element or contains little nitrogen element, even if it is subjected to wavelength conversion of a laser beam and irradiated with an ultraviolet laser beam with a wavelength of 40 Onm or less, nitric acid such as cesium nitrate Since no compound is produced, the wavelength conversion laser beam is not distorted by the nitric acid compound and the output is not further reduced, and since the inside of the wavelength conversion device 7a is not evacuated, No impurities are generated from the container, and no impurities adhere to the nonlinear optical crystal 2 or the optical window. This has the effect that a high-powered wavelength-converted laser beam can be generated.
• the gas 16 flows into the container 11 and flows so as to always flow out of the container 11, so that even if impurities are generated, the gas 16 is discharged together with the flowing gas 16. Therefore, it is possible to prevent impurities from adhering to the nonlinear optical crystal 2 and the optical windows 3a and 3b.
• the wavelength converter 7a does not need to be a strictly airtight container, and it is possible to stably generate a high-output wavelength-converted laser beam for a long period of time simply by flowing a small amount of rare gas, oxygen, carbon dioxide, etc. Therefore, the wavelength converter can be provided at a low cost.
• CLBO cesium-lithium-borate
• CsB 3 0 5, abbreviation: CBO cesium-borate
• cesium such as crystal Although the crystal is suitable, including, lithium 'borate (chemical formula: L iB 3 0 5, abbreviation: LB ⁇ ) crystal, base Isseki' Bruno, 'potassium borate (chemical formula:?
• the cylindrical shape of the container 11 is shown as an example, the shape may be any shape, for example, a cube or a rectangular parallelepiped.
• plugs 14a and 14b are described as being directly connected to the container 11 by, for example, a PT screw or a ring, other plugs provided in the middle of the pipe can be used.
• Example 1 the stoppers 14a and 14b were connected with I j to contain nitrogen element.
• a gas 16 containing no or low nitrogen element was constantly flowed.
• the stopper 14a After filling the inside of the vessel 11 with a gas 16 containing no or low nitrogen element, the stopper 14a, The gas 16 may be sealed in the container 11 by closing 14 b, that is, a cell in which the nonlinear optical crystal is sealed may be used, and the same effect as in the first embodiment can be obtained. However, in this case, the effect of flowing the gas 16 cannot be obtained.
• FIGS. 3 and 4 are diagrams for explaining a wavelength conversion method and a wavelength conversion device according to a second embodiment for carrying out the present invention. More specifically, FIG. FIG. 4 is a cross-sectional view of the wavelength converter.
• FIGS. 3 and 4 2, 3 a, 3 b, 4 a, 4 b, 11, 12 a, 12 b, 13 a, 13 b, 14 a, 14 b, 15a, 15b, and 16 are the same as those shown in the first embodiment, and have the same functions.
• 17 c and 17 d are fixing jigs for fixing the nonlinear optical crystal 2 on the heating element 18.
• Reference numeral 18 denotes a heating element provided with an electric heating heater. 19 is a heat insulating material. 7b shows the entire wavelength converter.
• a temperature sensor for monitoring the temperature is provided in the heating element 18, and the heating element 18 and the temperature sensor are connected to a wavelength converter 7 through an unillustrated electric wire.
• the heating element 18 connected to the external temperature controller is controlled by the temperature controller to control the current flowing through the electric heater in response to the signal from the temperature sensor, and to control the temperature to a constant temperature exceeding 100 ° C.
• the temperatures of the fixing jigs 17c and 17d and the nonlinear optical crystal 2 are kept at a constant temperature of 100 ° C. or more.
• the laser beam enters the container 11 through the optical window 3a on the input side, and is nonlinear. After the wavelength is converted by the optical crystal 2, the light is emitted from the optical window 3b on the output side.
• the wavelength converter 7b is configured as described above, and the nonlinear optical crystal 2 is kept at a constant temperature of 100 ° C. or higher. As a result, even when the gas 16 contains a small amount of water, the nonlinear optical crystal 2 does not absorb the water, so that the wavelength conversion laser beam can be generated stably for a long period of time. .
• the incident end face of the nonlinear optical crystal 2 on which the wavelength-converted light is incident and the exit end face on which the wavelength-converted light exits do not contain a nitrogen element, or Is exposed to gas 16 with a small amount of nitrogen, and even if the laser beam is wavelength-converted and irradiated with an ultraviolet laser beam with a wavelength of 400 nm or less, nitric acid compounds such as cesium nitrate are not generated.
• the inside of the wavelength conversion device 7a is not evacuated, no impurities are generated from the container, so that a high-quality and high-output wavelength conversion laser beam can be stably generated for a long period of time. This has the effect.
• the wavelength conversion device 7b does not need to be a vacuum vessel, there is an effect that the wavelength conversion device can be provided at a low cost.
• the impurities are exhausted together with the flowing gas 16, so that there is an effect that the impurities can be prevented from adhering to the nonlinear optical crystal 2 and the optical windows 3 a and 3 b. . '
• the container 11 is shown as having a cylindrical shape as an example, it may have any shape, for example, a cube or a rectangular parallelepiped.
• plugs 14a and 14b are described as being directly joined to the container 11 by, for example, a PT screw or an O-ring, other plugs provided in the middle of the pipe can be used.
• an electric heater is provided as the heating element 18 .
• the present invention is not limited to this, and a device capable of heating such as a Peltier device may be provided.
• Example 2 an example was described in which the stoppers 14 a and 14 b were opened and a gas 16 containing no nitrogen element or containing a small amount of nitrogen element was constantly flowed. After filling with gas 16 containing no or low nitrogen element, the stoppers 14a and 14b may be closed and the gas 16 may be sealed in the container 11 for use.
• the effect is the same as in Example 2. However, in this case, the effect of flowing the gas 16 cannot be obtained.
• FIG. 5 is a diagram for explaining a wavelength conversion method and a wavelength conversion device according to a third embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion device.
• FIG. 5 2, 16, 17a and 17b are the same as those shown in the first embodiment and have the same function.
• 35 is a container body
• 36a and 36b are lids
• 37 is a container.
• 38 a and 38 b are holes through which light drilled in the lids 36 a and 36 b passes.
• 13 c is a hole made in the container body 35.
• 14 c is a stopper.
• 15 c is a pipe. 7c shows the entire wavelength converter.
• the container 37 consists of the container body 35 and the lids 36a and 36b, and the lid 36a and the lid 36b have holes 38a and 38b, respectively, through which light passes. ing.
• a gas 16 containing gas other than nitrogen as the main component for example, rare gas, oxygen gas, carbon dioxide
• a gas mainly composed of a gas is introduced.
• Gas 16 replaces the air in container 37 and fills container 37 with gas 16 It is discharged from holes 38a and 38b.
• the container 37 does not necessarily need to be airtight, and the atmosphere of the nonlinear optical crystal 2 may be a gas containing no nitrogen element or a gas containing little nitrogen element. Further, at least the gas in contact with the surface of the nonlinear optical crystal 2 from which the wavelength-converted light emits does not contain the nitrogen element or is a gas containing a small amount of the nitrogen element, and the same effect as in the first embodiment can be obtained. As in the case of the second embodiment, the non-linear optical crystal 2 may be kept at a constant temperature of 100 ° C. or more by providing the heating element 18 and the heat insulating material 19.
• the atmosphere of the nonlinear optical crystal 2 does not contain a nitrogen element or is a gas containing a small amount of nitrogen element, but the nitrogen element content is at least smaller than that of air. If it is a gas, high-output wavelength conversion can be performed more stably for a longer period of time than when the atmosphere is air.
• the volume content of nitrogen is preferably 10% or less, and more preferably 1% or less. Therefore, the gas mainly containing a rare gas, an oxygen gas, a carbonic acid gas, or the like to be flowed or sealed in the container in which the nonlinear optical crystal 2 is disposed does not need to be a high-purity gas, and is a low-grade, inexpensive gas. Gas can be used.
• a gas mainly composed of a rare gas, an oxygen gas, a carbon dioxide gas, or the like preferably has a volume content of 50% or more, for example, preferably 90% or more, and more preferably 99% or more. Good.
• FIG. 6 is a diagram for explaining a wavelength conversion method and a wavelength conversion device according to a fourth embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion device.
• Non-linear optical crystal 2 cut the end surfaces on the phase matching angle for generating the following ultraviolet laser Zabimu Wavelength 40 O nm by the wavelength conversion, it is polished, the container 1 1 by solid Teiji instrument 1 7 c, 1 7 d Fixed on top.
• the nonlinear optical crystal 2 is made of a CLB 0 crystal, and both end faces are cut and polished at a phase matching angle for converting a laser beam having a wavelength of 532 nm into an ultraviolet laser beam having a wavelength of 266 nm. .
• the laser beam enters the container 11 from the input side optical window 3a, is wavelength-converted by the nonlinear optical crystal 2, and then exits from the output side optical window 3b.
• the gas 16a enters the space in contact with the incident end face of the nonlinear optical crystal 2 in the vessel 11 from the pipe 15b through the plug 14b and the hole 13b, and enters the incident end face of the nonlinear optical crystal 2.
• the gas is brought into contact with the atmosphere of gas 16a, which is discharged out of the container 11 through the hole 13a, the plug 14a, and the pipe 15a.
• the gas 16 b passes from the pipe 15 c through the plug 14 c and the hole 13 c into the space in contact with the output end face of the nonlinear optical crystal 2 in the container 11, and the output end face of the nonlinear optical crystal 2
• the atmosphere in contact with is the atmosphere of gas 16 b, and holes 1 3 d, 14 d of taps, 15 d of piping, and are discharged out of the container 11.
• the wavelength conversion device 7d is configured as described above, and the emission end face of the nonlinear optical crystal 2 contains a gas containing no nitrogen element or a gas containing a small amount of nitrogen element 16. b), the wavelength of the laser beam is converted, and even if the exit end face of the nonlinear optical crystal 2 is irradiated with an ultraviolet laser beam having a wavelength of 400 nm or less, nitric acid such as cesium nitrate can be used. No compound is generated, and the nitric acid compound does not cause distortion or decrease in output of the wavelength conversion laser beam, so that a high-quality and high-output wavelength-converted laser beam is stable for a long period of time. This has the effect of being able to occur.
• nitric acid such as cesium nitrate
• the wavelength-converted light that is, the fundamental wave of wavelength conversion
• the interaction between the nonlinear optical crystal 2 and the atmosphere caused by the incident laser beam and the interaction between the nonlinear optical crystal 2 and the atmosphere caused by the wavelength-converted light, that is, the wavelength-converted laser beam, are efficiently and individually prevented. It has the effect of being able to Furthermore, since the wavelength converter 7d does not need to be a vacuum container, there is an effect that no impurities are generated from the container and the wavelength converter can be provided at a lower cost.
• the gas 16a flows into a space in contact with the incident end face where the wavelength-converted light of the nonlinear optical crystal 2 in the container 11 is incident, and then flows out of the space. Since it is circulating, even if impurities are generated, it is discharged together with the circulating gas 16a. Further, the gas 16 b flows into a space in contact with the emission end face from which the wavelength-converted light of the nonlinear optical crystal 2 in the container 11 is emitted, and then flows out of this space. Because of the flow, even if impurities are generated, along with the flowing gas 16 b Is discharged. Therefore, it is possible to prevent an impurity from adhering to the nonlinear optical crystal 2 and the optical windows 3a and 3b.
• a heating element 18 and a heat insulating material 19 are provided, and by keeping the nonlinear optical crystal 2 at a constant temperature of 100 ° C. or more, trace amounts of gas 16a and 16b are reduced. Even if it contains moisture, it does not absorb moisture, so that there is an effect that a wavelength-converted laser beam can be stably generated for a long period of time.
• the heating element 18 and the heat insulating material 19 need not always be provided.
• the gas used in Example 4 that does not contain or contains a small amount of nitrogen is at least a gas having a lower content of nitrogen than air, compared with a gas having an atmosphere of air. As a result, a device that can perform high-output wavelength conversion stably for a long time is obtained.
• the nitrogen volume content is preferably 10% or less, more preferably 1% or less.
• the present inventors conducted further tests in order to investigate the cause of deterioration in wavelength conversion characteristics using a CLBO crystal. For example, using the wavelength conversion device 7b described in Example 2, using a CLBO crystal as the nonlinear optical crystal 2, a laser beam having a wavelength of 532 nm is made incident on the CLBO crystal, and an ultraviolet laser beam having a wavelength of 266 nm is used.
• the atmosphere in contact with the CLBO crystal's 266 nm wavelength ultraviolet laser beam emission end face is a gas other than oxygen, such as argon, which is a gas with a lower nitrogen element content than air.
• an atmosphere in contact with the laser beam incident end face having a wavelength of 532 nm, a gas other than argon gas for example, a gas mainly composed of oxygen gas (O 2 ), air, or the like.
• the cesium-lithium-borate Ichito (chemical formula: C s L i B 6 ⁇ 10, abbreviated: CLB 0) crystal
• a cesium-borate (chemical formula: CsB 3 0 5, abbreviation: CB0)
• crystals containing cesium such as a crystal is suitable
• lithium 'volley Bok (chemical formula: L i B 3 0 5, abbreviation: LB 0) crystal
• based evening' Roh Riumu-borate (chemical formula:? one BaB 2 0 4 , Abbreviation: BB 0), gadolinium.
• Dithium calcium calcium oxyborate (chemical formula: Even crystals that do not contain cesium, such as GdYCOB) crystals, can be used because elements other than cesium may react with nitrogen to form nitrogen compounds.
• the stoppers 14a, 14b, 14c, and 14d are opened and the gases 16a and 16b flow constantly is described, but the stoppers 14a, 14b, 14c, and 14d come into contact with the incident end face of the nonlinear optical crystal 2 in the container 11.
• the stoppers 14a, 14b, 14c, and 14d come into contact with the incident end face of the nonlinear optical crystal 2 in the container 11.
• the cell may be used in a sealed state, that is, a cell in which the nonlinear optical crystal 2 is sealed, and the same effect as in the fourth embodiment can be obtained.
• the effect of flowing the gases 16a and 16b cannot be obtained.
• FIG. 7 is a diagram for explaining a wavelength conversion method and a wavelength conversion device according to a fifth embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion device.
• Reference numeral 19 is the same as that shown in the first and second embodiments, and has the same function.
• 4 c is an O-ring.
• 1 1a is a container.
• 11b is the lid of the container 11a.
• 45 is a fixing jig for fixing the heat insulating material 19.
• An angle adjuster 46 corresponds to a means for adjusting the angle of the nonlinear optical crystal 2 with respect to the incident light.
• Reference numeral 47 denotes a position adjuster corresponding to a means for adjusting the position at which the incident light passes through the nonlinear optical crystal 2.
• 7e indicates the entire wavelength converter.
• the angle adjuster 46 adjusts the angle of the nonlinear optical crystal 2 with respect to the laser beam
• the position adjuster 47 adjusts the laser beam passing position of the nonlinear optical crystal 2.
• the wavelength conversion device 7 e is configured as described above, and includes the angle adjuster 46 and the position adjuster 47.
• the angle adjuster 46 and the position adjuster 47 are reduced. Discoloration may occur in the portion passing through the X-ray beam.
• the position adjuster 47 shifts the laser beam passage portion of the nonlinear optical crystal 2 to a position where there is no discoloration, and the angle adjuster 4 6
• the output of the wavelength-converted laser beam can be returned to the output before the laser beam passage portion of the nonlinear optical crystal 2 is deteriorated. To extend the life of There is an effect that it is.
• the nonlinear optical crystal 2 is exposed to a gas 16 containing no nitrogen element or having a low nitrogen element. Therefore, the wavelength conversion of the laser beam is performed. No nitric acid compound such as cesium nitrate is generated even when irradiated with an ultraviolet laser beam of 100 nm or less, and impurities are generated from the container because the wavelength converter 7 e is not evacuated. Therefore, it is possible to stably generate a high-quality and high-output wavelength-converted laser beam for a long period of time.
• a heating element 18 and a heat insulating material 19 are provided, and by keeping the nonlinear optical crystal 2 at a constant temperature of 100 ° C. or more, a trace amount of gas 16 is obtained.
• the nonlinear optical crystal 2 does not absorb moisture even when the JP01 / 10905
• the present invention is not limited to this.
• a wavelength converter similar to that described in 1, 3, or 4 may be provided with an angle adjuster 46 and a position adjuster 47, and the same effect can be obtained in this case.
• FIG. 8 is a diagram for explaining a wavelength conversion method and a wavelength conversion device according to a sixth embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion device.
• the pipe 15 g is connected to a hole 13 e for putting the gas 16 b into the container 11, and is arranged so as to extend near the exit end face of the nonlinear optical crystal 2.
• the hole 13 f is provided at a position facing the pipe 15 g with the nonlinear optical crystal 2 interposed therebetween. 7f indicates the entire wavelength converter.
• the space in contact with the incident end face of the nonlinear optical crystal 2 and the space in contact with the output end face are separated by, for example, a partition wall. This is the same as in the fourth embodiment.
• the non-linear optical crystal 2 is cut and polished at both ends to a phase matching angle for generating an ultraviolet laser beam having a wavelength of 400 nm or less by wavelength conversion. It is fixed on the container 1 1 by Teiji instrument 1 7 c, 1 7 d.
• the nonlinear optical crystal 2 is made of a CLBO crystal, and both end faces are cut and polished at a phase matching angle for converting a laser beam having a wavelength of 532 nm into an ultraviolet laser beam having a wavelength of 266 nm. ing.
• the laser beam enters the container 11 from the input side optical window 3a, is wavelength-converted by the nonlinear optical crystal 2, and then exits from the output side optical window 3b.
• the gas 16a enters the space in contact with the incident end face of the nonlinear optical crystal 2 in the vessel 11 from the pipe 15b through the plugs 14b and 613b, and enters the incident end face of the nonlinear optical crystal 2.
• the atmosphere in contact with the gas was the atmosphere of gas 16a, which was discharged out of the container 11 through the hole 13a, the stopper 14a, and the pipe 15a.
• a predetermined flow rate for example, a flow rate of 0.1 liter Z
• the gas 16b flows into the vessel 11 from the pipe 15e through the stopper 14e, the hole .13e, and the pipe 15g.
• the atmosphere that flows into the vicinity of the exit end face of the nonlinear optical crystal 2 and is in contact with the exit end face of the nonlinear optical crystal 2 is the atmosphere of gas 16b, and passes through holes 13f, plugs 14f, and pipes 15: Drained out of container 11
• the flow rate of the gas 16b is, for example, from a gas cylinder (not shown) to a flow control valve (not shown) and a flow meter (not shown). It is adjusted by adjusting the flow control valve, and measured by the flow meter.
• the wavelength conversion device 7f is configured as described above, and in addition to the same effects as described in the fourth embodiment, the following effects are also obtained. .
• the emission end face of the nonlinear optical crystal 2 is kept at the emission end face. Fresh gas just flowing in 1 6 Since b is supplied, impurities are prevented from adhering to the exit end face of the nonlinear optical crystal 2, and also from adhering to the portion of the optical window 3b close to the nonlinear optical crystal 2, and high quality is stably provided for a long time. In addition, the effect that a high-power wavelength conversion laser beam can be generated is enhanced.
• a hole 13 f was provided at a position opposite to the pipe 15 g, which is the inlet of the gas 16 b into the container 11, with the nonlinear optical crystal 2 interposed. Even if impurities are generated from the constituent materials of the container, the impurities can be efficiently removed from the inside of the container 11, thereby preventing the impurities from adhering to the exit end face of the nonlinear optical crystal 2 and the optical window 3 and The effect of being able to stably generate a high-quality and high-output wavelength-converted laser beam for a long time is further enhanced.
• the gas 16b flows into the vicinity of the end face of the nonlinear optical crystal 2 only on the exit end face side of the nonlinear optical crystal 2, and is efficiently discharged from the hole 13f facing the inlet 15g.
• the impurities enter the nonlinear optical crystal 2. Adhesion to the end face and the portion of the optical window 3a near the nonlinear optical crystal 2 is prevented, and the effect of stably generating a high-quality and high-output wavelength-converted laser beam for a longer period of time is further enhanced.
• Example 6 the gas 16 was placed in the vessel 11 in the nonlinear optical crystal 2.
• 15 g of piping is used as a means for supplying at least near the exit end face of the above
• the present invention is not limited to this.
• the inner wall of the container 11 may reach the vicinity of the end face of the nonlinear optical crystal 2.
• the gas 16 may be supplied to the vicinity of the end face of the nonlinear optical crystal 2 directly from the holes 13b and 13e without using the pipe 15g, and the same effect as in the sixth embodiment can be obtained.
• Example 7 the same effect as in the sixth embodiment can be obtained.
• the atmosphere in contact with the incident end face of the nonlinear optical crystal 2 and the atmosphere in contact with the exit end face are converted into gases 16 & and 16 b of different components to perform wavelength conversion.
• a gas having a lower nitrogen element content than air is supplied to the vicinity of the entrance end face or exit end face of the nonlinear optical crystal 2 and then discharged.
• the atmosphere in contact with the input end face of the nonlinear optical crystal 2 and the atmosphere in contact with the output end face as described in Embodiments 1 to 3 and Embodiment 5 are gases having the same components.
• the gas 16 having a nitrogen element content lower than that of air is supplied to the vicinity of the input end face or the output end face of the nonlinear optical crystal. After, it may be discharged.
• FIG. 9 is a diagram for explaining a wavelength conversion method and a wavelength conversion device according to a seventh embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion device.
• 15a, 15b, 16, 17c, 17 d, 18, and 19 are the same as those shown in the first and second embodiments, and have the same functions.
• 15 g is a pipe in the same manner as described in Example 6 above, and serves as a means for supplying a gas 16 having a nitrogen element content lower than that of air to the vicinity of the nonlinear + optical crystal output end face.
• wave-Au conversion 1 shows the entire apparatus.
• the laser beam enters the container 11 from the input side optical window 3a, is wavelength-converted by the nonlinear optical crystal 2, and then exits from the output side optical window 3b.
• the gas 16 flows from the pipe 15 b to the stopper; L 4 b and the hole 13 b pass through the pipe 15 g connected to the hole 13 b.
• a predetermined flow rate for example, a flow rate of 0.1 liter
• the gas 16 flows from the pipe 15 b to the stopper; L 4 b and the hole 13 b pass through the pipe 15 g connected to the hole 13 b.
• the atmosphere in contact with the exit end face of the nonlinear optical crystal 2 is set to the atmosphere of gas 16, and the holes 13 a, the plugs 14 a, It is discharged out of the container 11 through the pipe 15a.
• the flow of the gas 16 is connected to the pipe 15b from, for example, a gas cylinder not shown in the figure, through a flow control valve not shown in the figure, and further through a flow meter not shown in the figure. It is adjusted by adjusting the flow control valve and measured by a flow meter.
• the wavelength conversion device 7 g is configured as described above, and in addition to the same effects as described in the second embodiment, the following effects are also obtained. .
• the gas 16 is caused to flow in the vicinity of the emission end face of the nonlinear optical crystal 2, even if impurities are generated from components and the like in the container 11, the impurities flow into the emission end face of the nonlinear optical crystal 2. Since fresh gas 16 is supplied, impurities are prevented from adhering to the exit end face of the nonlinear optical crystal 2, and furthermore, are prevented from adhering to the portion of the optical window 3b close to the nonlinear optical crystal 2, The effect of being able to stably generate a high-quality and high-output wavelength-converted laser beam for a long time is enhanced.
• the gas 16 is supplied to the vicinity of the output end face of the nonlinear optical crystal 2.
• the gas 16 is supplied to both the output end face and the input end face of the nonlinear optical crystal 2. May be configured.
• the means for supplying the gas 16 to at least the vicinity of the emission end face of the nonlinear optical crystal 2 in the container 11 is provided to the same wavelength conversion device as that described in the second embodiment. 5 g), but the present invention is not limited to this, and the gas 16 is placed in the same wavelength converter as described in Example 1, 3 or 4 by using the nonlinear optical crystal in the vessel 11.
• a means (pipe 15 g) for supplying at least in the vicinity of the emission end face may be provided, and the same effect can be obtained in this case.
• Example 7 the case where the pipe 15 g was used as a means for supplying the gas 16 to the vicinity of the entrance end face or the exit end face of the nonlinear optical crystal 2 in the vessel 11 was shown, but the present invention is not limited to this.
• the inner wall of the container 11 is configured to reach the vicinity of the end face of the nonlinear optical crystal 2, and the nonlinear optical crystal 2 is directly formed from the holes 13b and 13e without using the piping 15g.
• a gas 16 may be supplied in the vicinity of the end face, and the same effects as those of the above-described seventh embodiment can be obtained.
• FIG. 10 is a view for explaining a wavelength conversion laser device according to an eighth embodiment for carrying out the present invention, and more specifically, is a longitudinal sectional view of the wavelength conversion laser device.
• reference numeral 2 denotes a nonlinear optical crystal.
• 7a is the above Example 1
• the wavelength converter shown in FIG. Reference numeral 20 denotes a laser device that generates a laser beam having a wavelength of 532 nm, which is the second harmonic of a neodymium-Yag (Nd: YAG) laser.
• Reference numeral 21 denotes a laser beam having a wavelength of 532 nm emitted from the laser device 20.
• Reference numeral 21a denotes a laser beam in which a part of the laser beam 21 having a wavelength of 532 nm is converted into a wavelength of 266 nm by the nonlinear optical crystal 2.
• Reference numeral 22 denotes a coated wavelength selective mirror that transmits a laser beam having a wavelength of 266 nm and reflects a laser beam having a wavelength of 532 nm.
• 21 b is an ultraviolet laser beam having a wavelength of 2666 nm.
• 23 is a base.
• Reference numeral 24 denotes a fixing table for fixing the wavelength conversion device 7a on the base 23.
• Reference numeral 25 denotes a fixing jig for fixing the wavelength selection mirror 22 on the base 23. 26 indicates the entire wavelength conversion laser device.
• Non-linear optical crystal 2 for example, cesium 'lithium' borate (chemical formula: C s L iB 6 O 10 abbreviated: CLBO) crystals, cesium 'Bole Ichito (chemical formula: C sB 3 0 5, abbreviation: CBO) crystal, lithium ⁇ borate (chemical formula: L iB 3 0 5, abbreviation: LB 0) crystal, Baie Isseki 'barium' borate (I ⁇ formula: beta-aB 2 ⁇ 4, abbreviation: BBO), Gadoriniumu 'yttrium' Cal Shiumu ' Okishiboreto (formula: Gd x YhC a 4 (B0 3) 3, abbreviation: G dYCOB) crystals made like, cut end surfaces in the phase matching angle for generating the following ultraviolet laser beam wavelength 40 O nm by the wavelength conversion It is polished and fixed on the container 11 by fixing jigs 17a and 17b.
• the nonlinear optical crystal 2 is made of a CLBO crystal, and both end faces are cut and polished to a type 1 phase matching angle for converting a laser beam with a wavelength of 532 nm into an ultraviolet laser beam with a wavelength of 266 nm. I have.
• the laser beam 21 having a wavelength of 532 nm emitted from the laser device 20 is incident on the wavelength conversion device 7 a, and a part of the laser beam 21 is converted to a wavelength of 26 nm by the nonlinear optical crystal 2.
• the laser beam becomes 21a.
• Laser beam 21a is transmitted by the wavelength selection mirror 22 to only the 266 nm wavelength component, and the 532 nm wavelength component is reflected, thereby forming an ultraviolet laser beam 21b having a 266 nm wavelength.
• the wavelength conversion laser device is configured as described above, and the nonlinear optical crystal 2 is exposed to a gas containing no nitrogen element or containing little nitrogen element.
• nitric compounds such as cesium nitrate are not generated even when irradiated with an ultraviolet laser beam with a wavelength of 400 nm or less due to wavelength conversion. It has the effect of being able to occur.
• the wavelength conversion device 7a does not need to be a vacuum container, there is an effect that no impurities are generated from the container, and the wavelength conversion laser device can be provided at a low cost.
• neodymium-catcher grayed (Nd: YAG, formula N d: Y 3 A 1 5 0 12) laser device for generating a record one
• the beam of wavelength 532 nm which is the second harmonic of the laser an example has been described using 20 as the light source, the wavelength of the light source is not limited to this, for example, ytterbium 'catcher grayed (Yb: YAG, formula Yb: Y 3 a 1 5 ⁇ 12) ⁇ neodymium - Irufu (N d: YL Fs formula Nd: L i YF 4), neodymium Waivio one Four (Nd: YV0 4), titanium 'sapphire (T i: fundamental of Al 2 ⁇ 3), may be such as a second harmonic, the The same effect as in the eighth embodiment is obtained.
• FIG. 11 is a view for explaining a laser beam machine according to a ninth embodiment for carrying out the present invention, and more specifically, a longitudinal sectional view of the laser beam machine. is there.
• reference numeral 26 denotes the wavelength conversion laser device shown in the eighth embodiment.
• 27 is a galvanomira.
• Reference numeral 28 denotes a galvanomirror fixing jig for fixing the galvanomirror 27 at an angle to the ultraviolet laser beam 21b having a wavelength of 2666 nm emitted from the wavelength conversion laser device 26.
• 29 is an f0 lens.
• 3 1 is a mirror lens fixing jig.
• Reference numeral 32 denotes a processed product such as a printed circuit board or a green sheet, and in this case, a glass epoxy printed circuit board.
• 3 3 is a processing machine base.
• Reference numeral 34 denotes a processing machine including a galvanometer mirror 27, a galvanometer mirror fixing jig 28, a 0 lens 29, a lens fixing jig 30, a mirror lens fixing jig 31, and a processing machine base 33.
• the galvanomirror 27 is fixed to the mirror lens fixing jig 31 by the galvanomirror fixing jig 28, and is fixed on the processing machine base 33.
• the f 6> lens 29 is fixed to the mirror lens fixing jig 31 by the f 0 lens fixing jig 30, and is fixed on the processing machine base 33.
• the wavelength conversion laser beam 2 lb emitted from the wavelength conversion laser device 26 is incident on the galvano mirror 27, and the traveling direction is variably changed by the galvano mirror 27.
• the wavelength-converted laser beam 21b whose traveling direction has been changed enters the f0 lens 29, and is focused on the workpiece 32.
• the focused wavelength-converted laser beam 2 1 b makes a hole in the workpiece 32.
• the laser processing machine is configured as described above, and the wavelength conversion laser device 26 can stably generate the wavelength conversion laser beam 2 lb for a long period of time.
• the present invention has an effect that good and uniform processing can be performed, and provides a method of manufacturing a high-quality printed circuit board. Further, since the wavelength conversion device 7a does not need to be a vacuum vessel, there is also an effect that a laser processing machine can be provided at low cost.
• a galvanomirror 27 is provided to change the traveling direction of the wavelength conversion laser beam 21 b variably. However, a workpiece such as an XY stage is mounted on the base 33.
• a movable base for moving 32 it is also possible to provide a movable base for moving 32, or to provide both a galvanomirror 27 and a movable base.
• a galvanomirror 27 it is also possible to provide a movable base for moving 32, or to provide both a galvanomirror 27 and a movable base.
• a plano-convex lens, a biconvex lens, or the like may be provided.
• the workpiece 32 was made of a printed board made of another material, a green sheet, and an electronic device. Parts, metals, glass, etc. can be used as long as they can be processed, and any processing can be used, such as cutting, welding, engraving, marking, forming, etc. This produces the same effect as that of the ninth embodiment.
• the wavelength conversion laser device 26 can be used for long-term stable high-quality wavelength conversion without distortion. Since the laser beam 21b can be generated, there is an effect that stable and accurate processing can be performed stably for a long time, and a method of manufacturing a high-quality fiber grating can be provided.
• the wavelength conversion method and the wavelength conversion device according to the present invention can be used, for example, in a wavelength conversion laser device, and a laser processing machine can be configured using the wavelength conversion laser device. Since such a laser processing machine can perform uniform processing with high accuracy and stability for a long period of time, it can be advantageously used in various processing such as production of printed circuit boards and production of fiber gratings.

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• Physics & Mathematics (AREA)
• Nonlinear Science (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

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• 2001
  • 2001-12-12 WO PCT/JP2001/010905 patent/WO2002048786A1/ja active IP Right Grant
  • 2001-12-12 DE DE10195608T patent/DE10195608B4/de not_active Expired - Fee Related

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