JP5697145B2 - Birefringence phase matching wavelength conversion device and method for manufacturing the device - Google Patents

Description

  The present invention relates to a wavelength conversion device for converting the wavelength of laser light and a method for manufacturing the same, and more particularly to a birefringence phase matching wavelength conversion device formed by laminating a plurality of plates made of nonlinear optical crystals.

As a nonlinear optical crystal for generating deep ultraviolet light, β-BaB ₂ O ₄ (hereinafter referred to as BBO) that is transparent in the ultraviolet region and has a high nonlinear optical constant is widely used.
However, since BBO has a large birefringence, as shown in FIG. 8A, when a bulk crystal 50B is used as the wavelength conversion device 50, ordinary light (o-ray) indicated by a solid line in FIG. ) Is emitted along the incident optical axis, whereas the emission direction of the extraordinary light (e-ray) indicated by the thick solid line in FIG. There is a problem that the interaction length necessary for phase matching is limited.
As a method for compensating for this walk-off, as shown in FIG. 8 (b), a plurality of plates (here, the number of plates is defined as N) where the c-axis of the crystal is inclined by the phase matching angle θ with respect to the incident optical axis of light. = 2) is arranged by reversing the c-axis direction of the crystals of the plates 51a and 51b adjacent to each other to increase the interaction length and reduce the walk-off amount ΔZ ( For example, refer nonpatent literature 1).
When the total length of the wavelength conversion device 50 is the same, as shown in FIG. 8C, a large number of thin plates 52a and 52b are arranged so that the c-axis direction of the crystals of the adjacent plates 52a and 52b is reversed. The (N = 8) arrangement has a larger walk-off compensation (WOC) effect and higher conversion efficiency.

J.-J.Zondy, Ch.Bonnin and D.Lupinski, J.Opt.Soc. Am.B 20,1675 (2003)

However, in the conventional wavelength conversion device, in order to reduce the walk-off amount ΔZ, it is necessary to prepare a large number of thin plates, and in terms of productivity to be widely used as industrial devices. There are difficulties. In addition, since the wavelength conversion device is simply contacting the plates, not only can there be a gap at the plate joint surface, but a deviation occurs between the inclination of the c-axis and the phase matching angle θ. As a result, there is a problem that the conversion efficiency is greatly reduced.
As a method of joining two plates together, a method of performing pressure etching after chemically etching the surface is conceivable. However, in this case as well, a gap of an atomic level or more is formed at the interface between the two plates. It is difficult to obtain sufficient conversion efficiency because light is scattered at the interface.

  The present invention has been made in view of the conventional problems, and a birefringence phase matching wavelength conversion device capable of efficiently reducing the walk-off with a small number of plates and a birefringence phase matching wavelength conversion device having high conversion efficiency. An object of the present invention is to provide a method for easily manufacturing the above.

In order to solve the above-mentioned problems, the present invention includes a plurality of plates made of nonlinear optical crystals that are bonded to each other and in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction. The c-axis directions of the plates adjacent to each other are plane-symmetric with respect to the joining surface, and the incident side plate at the incident side end of the laser beam and the emission of the harmonics of the laser beam in a plurality of plates The thickness of the plate located between the exit side plate at the side end is the same, and the thickness of the entrance side plate and the exit side plate is the thickness of the plate located between the entrance side plate and the exit side plate. It was set as the structure which is 1/2.
According to this configuration, the walk-off amount of the wavelength conversion device can be made the same as the walk-off amount of the incident side plate and the emission side plate with a thin thickness (short crystal length), so the walk-off is effective with a small number of plates. Can be reduced.

As another configuration of the present invention, the nonlinear optical crystal is a β-BBO crystal or an LBO crystal.
According to the configuration of the present application, a birefringence phase matching wavelength conversion having a high conversion efficiency and a stable performance by using a β-BBO crystal or an LBO crystal, which is easy to obtain a high quality crystal as a nonlinear optical crystal and has a high damage threshold. You can get a device.

Further, as an aspect related to the manufacturing method, the plates having the same thickness made of nonlinear optical crystals in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction are bonded to each other in the c-axis direction. A process of activating the surface by irradiating one of an atomic beam, a molecular beam, and an ion beam on the surface that is a plane of symmetry with respect to the plate and irradiating the surface to be a bonding surface between the plates. Bonding the surfaces of the plates at room temperature , and having both thicknesses of the plates constituting the plate group at both ends of the joined plate group, and the c-axis of the crystal being thick When joining a plate made of a nonlinear optical crystal that is inclined with respect to the thickness direction in a plane parallel to the thickness direction, the plate having the thickness of 1/2 is symmetrical with respect to the joining surface in the c-axis direction. Facing each other and pre- A process of activating the surface by irradiating one of an atomic beam, a molecular beam, or an ion beam onto the surface to be a joint surface between the two, and a process of joining the surfaces of the activated plates at room temperature It was set as the aspect provided with.
According to the aspect of the present application, since the plates made of the nonlinear optical crystal in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction can be joined at an atomic level in a short time, conversion efficiency is improved. A high birefringence phase matching wavelength conversion device can be easily manufactured. Further, the plates made of a nonlinear optical crystal having a thickness that is 1/2 that of each plate constituting the plate group and in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction are short. It can be bonded at the atomic level in time, and the walk-off amount of the wavelength conversion device can be made the same as the walk-off amount of the entrance side plate and the exit side plate, making it easy to create a birefringence phase matching wavelength conversion device with high conversion efficiency. Can be manufactured.

Further, as another aspect relating to the manufacturing method, an aspect is provided that includes a step of applying a non-reflective coating only to the surface serving as the incident end face and the surface serving as the exit end face of the plate having a thickness of 1/2.
According to the aspect of the present application, since only the incident end face and the exit end face of the plate arranged on the incident side and the plate arranged on the exit side are coated, the loss at each joint surface can be greatly reduced, and the intermediate When the number of plates is increased, the same room temperature bonding condition is sufficient, so that the production efficiency is improved.
The summary of the invention does not list all necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

It is a figure which shows the structure of the birefringent phase matching wavelength conversion device which concerns on embodiment of this invention. It is a figure for demonstrating operation | movement of a birefringence phase matching wavelength conversion device. It is a flowchart which shows the manufacturing method of the birefringence phase matching wavelength conversion device which concerns on this Embodiment. It is a figure which shows an example of the cutting method of a plate. It is a schematic diagram which shows the structure of a room temperature bonding apparatus. It is a figure which shows the joining method of a plate. It is a figure which shows the conversion characteristic of a birefringence phase matching wavelength conversion device. It is a figure which shows the structure of the conventional birefringence phase matching wavelength conversion device.

  Hereinafter, the present invention will be described in detail through embodiments, but the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

1A and 1B are diagrams showing an embodiment of the present invention, in which FIG. 1A shows a birefringence phase matching wavelength conversion device (hereinafter referred to as a wavelength conversion device), and FIG. 1B shows each plate of the wavelength conversion device. The figure which shows the relationship with the c-axis of a crystal | crystallization, (c) A figure is a figure which shows the relationship between the optical axis direction of incident light and normal light, and the c-axis of the crystal | crystallization of a plate.
The wavelength conversion device 10 of this example includes a plurality of plates made of a single crystal (hereinafter referred to as BBO) of β-BaB ₂ O ₄ which is a nonlinear optical crystal, and the wavelength incident from the laser device 20 is λ ₁ = A wavelength of 532 nm laser light (fundamental wave) is converted, and a laser light having a wavelength of λ ₂ = 266 nm, which is the second harmonic (SH) of the fundamental wave, is emitted. Each plate is joined by a room temperature joining method to be described later with plate surfaces adjacent to each other as joining surfaces.
The plate constituting the wavelength conversion device 10 includes four plates 11 (111 to 114) having a thickness of d and two plates 12 (121, 122) having a thickness of d / 2. The plate 122 is disposed on the incident side of the laser device 20, and the plate 122 is disposed on the emission side of the wavelength conversion device 10 of the laser device 20.
The plates 111 to 114 are disposed between the plate 121 and the plate 122. Hereinafter, as necessary, the plate 121 is referred to as an incident side plate, the plate 122 is referred to as an output side plate, and the plates 111 to 114 are referred to as intermediate plates.
The plates 11 and 12 and the plates 11 and 11 are arranged so that the c-axis directions of the crystals of the plates adjacent to each other are plane-symmetric with respect to the bonding surface.
Here, the direction perpendicular to the plate surface of the plate that is the optical axis direction of ordinary light that is the left-right direction in FIG. 1A is the thickness direction or the x-axis direction, and the direction perpendicular to the paper surface is the width direction or the y-axis direction. When the vertical direction is the height direction or the z-axis direction, the c-axis of the plate 121 and the c-axis of the plates 112 and 114 are counterclockwise with respect to the thickness direction in a plane parallel to the thickness direction (zx plane). It is tilted around the phase matching angle θ. On the other hand, the c-axis of the plate 122 and the c-axis of the plates 111 and 113 are inclined by (π−θ) with respect to the thickness direction in a plane parallel to the thickness direction (zx plane). The phase matching angle θ varies depending on the type of nonlinear optical crystal and the incident wavelength, but in the case of BBO, the phase matching angle θ is in the range of 45 ° to 50 °, for example.

Next, the operation of the wavelength conversion device 10 having the above configuration will be described with reference to FIG.
Laser light with a wavelength of λ ₁ = 532 nm emitted from the laser device 20 is perpendicularly incident on the plate surface on the laser device 20 side of the incident side plate 121 that is the incident end surface of the wavelength conversion device 10. This incident light is birefringent at the incident end face of the incident side plate 121 and separated into ordinary light (o-ray) and extraordinary light (e-ray). Ordinary (o-ray) refractive index n _o of is not angular dependence with respect to the optical axis of the incident light, the refractive index n _e of the extraordinary light (e-ray) is an optical axis of the crystal and the optical axis of the incident light c Since it varies depending on the angle formed with the axis, ordinary light (o-ray) travels straight in the direction of incidence of laser light, and extraordinary light (e-ray) is refracted in the −z direction.
Since the c-axis of the incident side plate 121 is inclined by the BBO phase matching angle θ, the ordinary light (o-ray) and the extraordinary light (e-ray) are phase-matched. As a result, the second harmonic (SH; wavelength λ ₂ = 266 nm) of the laser light having a fundamental wave of λ ₁ = 532 nm is emitted from the emission end face of the second plate 111. When the walk-off angle that is an angle formed by ordinary light (o-ray) and extraordinary light (e-ray) is ρ, the walk-off amount in the incident side plate 121 is ΔZ = (d / 2) · tan ρ.
The ordinary light (o-ray) and extraordinary light (e-ray) emitted from the incident side plate 121 are incident on the intermediate plate 111 on the laser device 20 side, and the ordinary light (o-ray) travels straight in the incident direction of the laser light. .
On the other hand, in the intermediate plate 111, the c-axis direction is arranged so as to be plane-symmetric with respect to the c-axis and the joint surface of the adjacent incident-side plate 121, so abnormal light (e-ray) is in the + z direction, That is, the light is refracted in the traveling direction of ordinary light (o-ray). Thereby, since the interaction length becomes long, the conversion efficiency is improved.
The amount of deviation of the extraordinary light (e-ray) at the intermediate plate 111 is twice the amount of Δz ′ = d · tanρ and the walk-off amount ΔZ of the incident side plate 121, but the optical axis direction of ordinary light (o-ray) The walk-off amount ΔZ ′, which is a deviation amount, is equal to the walk-off amount ΔZ in the incident side plate 121 at ΔZ ′ = (d / 2) · tanρ.

Similarly, the intermediate plates 112, 113, and 114 are disposed so that the c-axis direction is plane-symmetric with respect to the c-axis direction and the joint surface of the adjacent intermediate plates 111, 112, and 113, respectively. The extraordinary light (e-ray) is refracted in the −z direction in the intermediate plate 112, in the + z direction in the intermediate plate 113, and in the −z direction in the intermediate plate 114. At this time, the amount of deviation of the extraordinary light (e-ray) at the intermediate plates 112, 113, 114 is Δz ′ = d · tanρ. Further, the walk-off amount ΔZ ′ is equal to the walk-off amount ΔZ in the incident side plate 121 and the intermediate plate 111.
The ordinary light (o-ray) and extraordinary light (e-ray) emitted from the end side intermediate plate 114 are incident on the emission-side plate 122, and the ordinary light (o-ray) travels straight in the incident direction of the laser light. The light is emitted from a plate surface of the emission side plate 122 opposite to the laser device 20. Since the c-axis direction of the crystal of the emission side plate 122 is arranged so as to be plane-symmetric with respect to the c-axis and the joint surface of the intermediate plate 114 on the end side, the extraordinary light (e-ray) is in the + z direction. Refracted and emitted.
Since the emission side plate 122 is half the thickness of the intermediate plate 114, both the amount of abnormal light (e-ray) deviation Δz and the amount of walk-off ΔZ are Δz = ΔZ = (d / 2) · tanρ.
Thus, in the wavelength conversion device 10, even when four plates 111 to 114 having a thickness of d are used as intermediate plates, the walk-off amount is the same as that when a plate having a thickness of d / 2 is used. Since ΔZ = (d / 2) · tanρ, the walk-off can be effectively reduced with a small number of plates.

Next, the manufacturing method of the wavelength conversion device 10 of this invention is demonstrated based on the flowchart of FIG. First, from a BBO single crystal grown by the CZ method (chocolasky method) or the flux method, a predetermined area (here, one side is d and d / 2 (here, 1 mm and 0.5 mm) in thickness) A plurality of 5 mm square plate plates are cut out (step S10).
As shown in FIG. 4, the BBO crystal wafer usually has the c-axis direction oriented in the p-direction, which is the thickness direction of the wafer 55. What is necessary is just to cut out so that the angle which becomes may become (90 degrees-(theta)). As a result, it is possible to obtain a plate that is inclined by the phase matching angle θ with respect to the thickness direction x in a plane perpendicular to the cut-out surface where the c-axis direction after cut-out is a bonding surface.
Here, four plates with a thickness of d are used as intermediate plates, and two plates with a thickness of d / 2 are used as end side (incident side and outgoing side) plates. 5, the vacuum chamber 31, the first and second sample holders 32 and 33 installed in the vacuum chamber 31, and the side surfaces of the first and second sample holders 32 and 33. Bonding is performed using a room temperature bonding apparatus 30 provided with a beam source 34.
First, the two plates 111 and 112 serving as intermediate plates among the plates are attached to the sample attachment surfaces 32a and 33a of the first and second sample holders 32 and 33, respectively (step S11). At this time, the plates 111 and 112 are mounted facing each other so that the c-axis direction of the crystals of the plates 111 and 112 is symmetric with respect to the bonding surface. Here, the sample mounting surfaces 32a and 33a of the first and second sample holders 32 and 33 are horizontal surfaces, and the direction perpendicular to these surfaces is the vertical direction. In this example, the first sample holder 32 is a movable holder, and the second sample holder 33 is a fixed holder. The first sample holder 32 moves up and down in the direction of the second sample holder 33 by an elevator mechanism (not shown).
The beam source 34 is an apparatus that irradiates an Ar beam onto the planned joining surface of the plate, and the center of the irradiated Ar beam is at a position away from the sample mounting surface 33a of the second sample holder 33, which is a fixed holder. Arranged so that.

When the attachment of the plates 111 and 112 is completed, the vacuum chamber 31 is closed, and the vacuum chamber 31 is evacuated by a vacuum pump (not shown) until a high vacuum of 10 ⁻⁵ Pa or less is reached (step S12). After a certain first sample holder 32 is lowered in the direction of the second sample holder 33, which is a fixed holder, the distance between the surface 111a of the plate 111 and the surface 112a of the plate 112 becomes a predetermined distance d. Hold (step S13).
Then, after the inside of the vacuum chamber 31 reaches a predetermined degree of vacuum, as shown in FIG. 6A, the beam source 34 is operated, and the Ar beam is applied to the surfaces 111a and 112a of the plates 111 and 112 for a predetermined time. Irradiation is performed to etch the surfaces 111a and 112a (step S14). Thereby, the surface 111a, 112a of the plates 111, 112 can be activated.
The conditions for the activation treatment are as follows: the spread angle of the Ar beam is ω = 10 ° to 30 °, the distance d between the two plates 111 and 112 is 1 to 5 mm, and the irradiation energy density of the Ar beam is 90 to 1200 J / A range of cm ² is preferable. Thereby, not only the surfaces 111a and 112a of the plates 111 and 112 can be uniformly etched, but also the surface 111a and 112a can be appropriately activated since they are not etched deeply unnecessarily as in the case of chemical etching. . Therefore, bonding at the atomic level can be reliably performed, and conversion efficiency can be improved.

When the activation processing of the surfaces 111a and 112a of the plates 111 and 112 is completed, the irradiation of the Ar beam is stopped and the second sample holder 33 is moved to the first sample holder 32 as shown in FIG. The surface 111a of the plate 111 and the surface 112a of the plate 112 are brought into close contact with each other, and the plate 111 and the plate 112 are joined at room temperature (step S15). In this example, since the interval d between the two plates 111 and 112 is 1 to 5 mm, the joining can be performed in a short time of about 1 to 3 seconds.
Thereafter, the vacuum pump is stopped, an inert gas is introduced into the vacuum chamber 31, the interior of the vacuum chamber 31 is returned to atmospheric pressure, the vacuum chamber 31 is opened, and the plate 111 and the plate 112 are joined. The composite plate 10A thus taken out is taken out (step S16).

Next, the composite plate 10A is attached to the first sample holder 32, and a new plate 113 is attached to the second sample holder 33 (step S17). At this time, the direction of the c-axis of the crystal of the new plate 113 attached to the second sample holder 33 and the c-axis of the plate 112 on the planned joining surface side of the composite plate 10A attached to the first sample holder 32 It is mounted so that the direction is symmetrical with respect to the joint surface.
Then, the operations from Step S12 to Step S14 are performed, and as shown in FIG. 6C, after the surface 113a of the new plate 113 and the surface of the composite plate 10A are activated, the process proceeds to Step S15. As shown in FIG. 6D, a new plate 113 and a composite plate 10A are joined at room temperature to obtain a composite plate 10B in which three plates 111, 112, 113 are joined.
By repeating the same operation, a composite plate 10C obtained by joining the four intermediate plates 111 to 114 is obtained (see FIG. 6E for the composite plate 10C).

Next, as shown in FIG. 6E, one of the composite plate 10C and the end side plate 12 (incident side plate 121 or outgoing side plate 122) is joined at room temperature (step S18). At this time, the non-reflective coating process is performed in advance on the surface to be the incident end surface or the output end surface of the end portion side plate 12. Then, the c-axis direction of the crystal of the end side plate 12 and the c-axis direction of the plate 111 on the planned joining surface side of the composite plate 10C attached to the first sample holder 32 are symmetrical with respect to the joining surface. As described above, the composite plate 10C is attached to the first sample holder 32, and the operations from step S12 to step S14 are performed, so that the surface of the end plate 12 and the surface of the composite plate 11a are activated. . Then, it progresses to step S15 and the edge part side plate 12 and the composite plate 11b are joined at normal temperature, and the composite plate 10D which consists of the edge part side plate 12 and the intermediate | middle plates 111-114 is obtained.
Finally, as shown in FIG. 6 (f), the other plate of the end side plates 12 and the composite plate 10D are joined at room temperature (step S19), so that the wavelength conversion device as shown in FIG. 10 can be obtained.

7 was produced using a room temperature bonding apparatus 30, the thickness of the four plates and thickness two wavelength conversion device of the full-length consisting plate of 5mm of 0.5mm of 1 mm, wavelength lambda ₁ = 532 nm laser light (fundamental wave) is incident, and the fundamental power (Fundamental Power; [W]) when the second harmonic (SH) of the laser light having a wavelength of λ ₂ = 266 nm is generated. As a comparative example, the graph also shows the measurement results of a wavelength conversion device manufactured using a bulk crystal as a comparative example, and shows the relationship between the power of the second harmonic (SH) (SH Power; [μW]). The walk-off angle at this time is about 4.8 °.
Moreover, the manufacturing conditions of the wavelength conversion device according to the present invention are as follows.
Degree of vacuum ... 2.0 × 10 ^-6 Torr
Ar beam: current: 2 mA, voltage: 5 kV,
Spreading angle: 20 °, irradiation time: 60 seconds Distance between samples: 2 mm
Beam-sample distance: 10 mm
Bonding time: 2 seconds It can be seen from the graph of FIG. 7 that the wavelength conversion device according to the present invention can provide an output that is approximately twice that of a wavelength conversion device manufactured using a bulk crystal. Thus, it was confirmed that a birefringence phase matching wavelength conversion device capable of efficiently reducing the walk-off with a small number of plates can be easily manufactured.

In the above-described embodiment, the wavelength conversion device 10 is configured by the two end side plates and the four intermediate plates 11. However, the present invention is not limited to this. If the number is further increased, the walk-off can be further reduced and the conversion efficiency can be improved. Also in this case, the c-axis of the crystal is tilted by the phase matching angle θ with respect to the thickness direction in a plane parallel to the thickness direction, and the directions of the c-axis of two plates adjacent to each other are Needless to say, they are arranged so as to be plane-symmetric with respect to the surfaces to be joined, and the thickness of the end side plate 12 is set to half the thickness of the intermediate plate 11.
In the above example, the intermediate plate 12 is first joined at room temperature, and then the room temperature joined intermediate plate and the end side plate are joined at room temperature, but the order of room temperature joining is not limited to this, and the end side Room temperature bonding may be performed in order from the plate.
In the above example, the β-BBO crystal is used as the nonlinear optical crystal, but another nonlinear optical crystal such as an LBO crystal, a CLBO crystal, or a KTP crystal may be used. Among these, β-BBO crystals and LBO crystals are easy to obtain high-quality crystals, and have a high damage threshold, so that high conversion efficiency and stable performance can be obtained.
In the above example, the surfaces of the plates 11 and 12 are etched with an Ar atomic beam, but a molecular beam or an ion beam may be used.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the embodiment. It is apparent from the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  According to the present invention, since the walk-off can be effectively reduced with a small number of plates, the productivity of the birefringence phase matching wavelength conversion device can be improved. In addition, since the plates are joined at room temperature, a birefringence phase matching wavelength conversion device having high conversion efficiency and stable performance can be easily provided.

10 birefringence phase matching wavelength conversion device, 11, 111-114 intermediate plate,
12, 121, 122 End side plate, 20 laser device.

Claims (4)

A plurality of plates composed of nonlinear optical crystals that are bonded together and in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction;
The c-axis directions of the plates adjacent to each other in the arrangement of the plurality of plates are plane symmetric with respect to the joint surface
The thickness of the plate located between the incident side plate of the incident side end of the laser beam in the plurality of plates and the emission side plate of the emission side end that emits harmonics of the laser beam is the same, A birefringence phase-matching wavelength conversion device, wherein the incident side plate and the outgoing side plate have a thickness that is ½ of the thickness of the plate located between the incident side plate and the outgoing side plate.   The birefringence phase matching wavelength conversion device according to claim 1, wherein the nonlinear optical crystal is a β-BBO crystal or an LBO crystal. Plates of the same thickness made of nonlinear optical crystals in which the c-axis of the crystal is inclined with respect to the thickness direction in a plane parallel to the thickness direction are arranged so that the c-axis direction is plane-symmetric with respect to the bonding surface. A process of activating the surface by irradiating any one of an atomic beam, a molecular beam, and an ion beam on the surface to be a bonding surface between the plates;
Joining the surfaces of the activated plates at room temperature;
At both ends of the joined plate group, the plate group has a half thickness of each plate constituting the plate group, and the c-axis of the crystal is parallel to the thickness direction with respect to the thickness direction. When a plate made of a nonlinear optical crystal tilting is joined, the plate having the thickness of 1/2 is opposed so that the c-axis direction is plane-symmetric with respect to the joining surface to form a joining surface between the plates. Irradiating the surface with either an atomic beam, molecular beam, or ion beam to activate the surface; and
Joining the surfaces of the activated plates at room temperature;
A method of manufacturing a birefringence phase matching wavelength conversion device comprising: Method for producing a birefringent phase matching wavelength conversion device of claim 3, further comprising the step of only surface to be the entrance end face the surface from the emitting end face processing antireflection coating in the plate having a thickness before Symbol 1/2.

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