JP7438057B2 - solid state laser oscillator - Google Patents

Description

The present invention relates to a solid-state laser oscillator.

Many solid-state laser oscillators such as Nd:YAG lasers, which are widely used as processing lasers, have a low absorption rate for wavelengths in the near-infrared region because their oscillation wavelength region is limited to the near-infrared region around 1 μm. The problem with materials is that processing efficiency is poor. For this reason, nonlinear optical crystals such as LiB ₃ O ₅ (lithium triborate; LBO), KTiOPO ₄ (KTP), and β-BaB ₂ O ₄ (barium baud rate; BBO) are used to adjust the oscillation wavelength to the second harmonic. A method has been proposed to improve processing efficiency by converting laser light into a shorter wavelength region such as a wave or third harmonic to reduce the reflectance on the surface of the workpiece and increase the absorption of laser light. (See Patent Document 1).

Wavelength conversion using a nonlinear optical crystal includes an external resonator wavelength conversion method in which the wavelength is converted outside the resonator, and an internal resonator wavelength conversion method in which the wavelength is converted inside the resonator. In order to increase the conversion efficiency from fundamental laser light to harmonic laser light, it is necessary to focus the fundamental laser light on a nonlinear optical crystal with high power density, so the internal cavity wavelength conversion method is , the conversion efficiency is superior compared to the resonator external wavelength conversion method.

A general solid-state laser medium hardly absorbs fundamental laser light, but often has high absorption characteristics for wavelength-converted laser light, especially laser light converted to a shorter wavelength. Therefore, in the resonator internal wavelength conversion method, in order to prevent the wavelength-converted laser light from entering the laser medium, a method is used to separate the fundamental laser light and the wavelength-converted laser light in the optical path inside the resonator. A dielectric multilayer mirror is arranged. This prevents the wavelength-converted laser beam from being absorbed by the solid-state laser medium, and allows only the wavelength-converted laser beam to be extracted outside the resonator, thereby efficiently extracting the wavelength-converted laser beam. ing.

Japanese Patent Application Publication No. 2007-53160

By the way, in wavelength conversion using a nonlinear optical crystal, two SHG (Second Harmonic Generation) optical axes are generated that are separated from each other by about several hundred micrometers due to the influence of walk-off due to birefringence of the wavelength conversion crystal. The mirror of a commonly used resonator called a confocal resonator is a concave mirror with curvature, so when it is taken out of the resonator, the light is emitted in an oblique direction due to the concave lens effect, and the distance between the two optical axes is It will spread further. As a result, the condensed spot is formed in a distorted manner due to the influence of aberrations, which poses a problem in that the quality of laser processing may be degraded.

The present invention has been made in view of such problems, and an object of the present invention is to provide an internal wavelength conversion type solid-state laser oscillator that can suppress the influence of walk-off caused by the wavelength conversion crystal.

In order to solve the above-mentioned problems and achieve the objects, the solid-state laser oscillator of the present invention includes a resonator configured by sandwiching a laser medium between a first mirror and a second mirror, and a resonator that includes a first mirror and a second mirror. a wavelength conversion crystal disposed between the laser medium and converting a fundamental wavelength laser beam oscillated by the laser medium into a second harmonic laser beam; and a wavelength conversion crystal disposed between the wavelength conversion crystal and the laser medium. A solid-state laser oscillator comprising: a dichroic mirror disposed between the wavelength converting crystal and reflecting the second harmonic laser beam wavelength-converted by the wavelength converting crystal toward the wavelength converting crystal and transmitting the fundamental wavelength laser beam; The first mirror is a plane mirror, and further includes a lens disposed between the laser medium and the dichroic mirror, and constitutes a confocal resonator as a whole.

The wavelength conversion crystal may be a Type-1 SHG crystal.

At least one of the first mirror and the dichroic mirror may be wedge-shaped.

The laser device may further include a light shielding member that is disposed between the dichroic mirror and the laser medium and shields light returning from the end face of the dichroic mirror.

The device may further include a condenser lens that condenses the laser beam, and an optical fiber that receives the laser beam condensed by the condenser lens.

Further, the solid-state laser oscillator of the present invention includes a resonator configured by sandwiching a laser medium between a first mirror and a second mirror, and a resonator disposed between the first mirror and the laser medium, A wavelength conversion crystal that converts a fundamental wavelength laser beam oscillated by a medium into a second harmonic laser beam, and a wavelength conversion crystal that is disposed between the wavelength conversion crystal and the laser medium, and converts the wavelength with the wavelength conversion crystal. a dichroic mirror that reflects a laser beam of a second harmonic wave to the wavelength conversion crystal side and transmits a laser beam of a fundamental wavelength, the first mirror being a flat mirror. The dichroic mirror is a concave mirror or a convex mirror.

The dichroic mirror may be adjustable in angle so that the laser beams separated by walk-off by the wavelength conversion crystal are superimposed at a predetermined position.

The present invention can provide an internal wavelength conversion type solid-state laser oscillator that can suppress the influence of walk-off caused by a wavelength conversion crystal.

FIG. 1 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to a first embodiment. FIG. 2 is a schematic diagram showing a focused state of a laser beam oscillated by the solid-state laser oscillator of FIG. FIG. 3 is a schematic diagram showing a focused state of a laser beam oscillated by a solid-state laser oscillator of a comparative example. FIG. 4 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the second embodiment. FIG. 5 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the third embodiment. FIG. 6 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the fourth embodiment. FIG. 7 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the fifth embodiment. FIG. 8 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the sixth embodiment. FIG. 9 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to the first modification. FIG. 10 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator according to a second modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Further, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[First embodiment]
First, a solid-state laser oscillator 1 according to a first embodiment will be explained based on the drawings. FIG. 1 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 1 according to the first embodiment. As shown in FIG. 1, the solid-state laser oscillator 1 includes a resonator 11, a wavelength conversion crystal 50, a dichroic mirror 61, and a lens 71. The resonator 11 is configured by sandwiching a laser medium 20 between a first mirror 31 and a second mirror 41. In the following description, the laser beam 120 generated by the solid-state laser oscillator 1 in the laser medium 20 will be referred to as the fundamental wavelength laser beam 130, and the laser beam 120 whose wavelength has been converted by the wavelength conversion crystal 50 will be referred to as the second harmonic. The laser beam 140 of FIG. The second harmonic laser beam 140 is a double wave of the fundamental wavelength laser beam 130.

The laser medium 20 is excited by an excitation source (not shown) to oscillate a laser beam 130 having a fundamental wavelength. A laser beam 130 having a fundamental wavelength oscillated from the laser medium 20 is reflected between the first mirror 31 and the second mirror 41 and is amplified by reciprocating. The laser medium 20 includes, for example, Nd:YAG crystal, Nd:YLF crystal, or the like. For example, a dielectric multilayer antireflection film is formed on the incident surface of the laser medium 20, through which the incident laser beam 130 of the fundamental wavelength is transmitted.

The first mirror 31 is arranged at the end of the output side of the resonator 11 that causes the laser beam 130 of the fundamental wavelength to reciprocate. A fundamental wavelength laser beam 130 and a second harmonic laser beam 140 are incident on the first mirror 31 . The first mirror 31 reflects the laser beam 130 at the fundamental wavelength. The first mirror 31 transmits the second harmonic laser beam 140 and emits it to the outside of the resonator 11 .

In the first embodiment, the first mirror 31 is a plane mirror in which both surfaces are flat and parallel. On the incident surface of the first mirror 31, a dielectric multilayer film is formed, for example, on which the fundamental wavelength laser beam 130 is reflected and the second harmonic laser beam 140 is transmitted.

The second mirror 41 is arranged at the end of the resonator 11 opposite to the output side on which the laser beam 130 of the fundamental wavelength is made to reciprocate. A laser beam 130 having a fundamental wavelength is incident on the second mirror 41 . The second mirror 41 reflects the laser beam 130 at the fundamental wavelength.

In the first embodiment, the second mirror 41 is a concave mirror in which a concave surface is formed on the incident surface. For example, a dielectric multilayer film is formed on the incident surface of the second mirror 41 to reflect the incident laser beam 130 of the fundamental wavelength.

The wavelength conversion crystal 50 is arranged on the optical axis between the first mirror 31 and the laser medium 20. The wavelength conversion crystal 50 converts the fundamental wavelength laser beam 130 oscillated by the laser medium 20 into a second harmonic laser beam 140. The wavelength conversion crystal 50 is, for example, a nonlinear optical crystal such as LBO, KTP, or BBO.

In the first embodiment, the wavelength conversion crystal 50 is a Type-1 SHG (Second Harmonic Generation) that emits the incident laser beam 130 of the fundamental wavelength as a second harmonic laser beam 140 that is a double wave thereof. It is a crystal. For example, a dielectric multilayer antireflection film is formed on the incident surface of the wavelength conversion crystal 50, through which the incident fundamental wavelength laser beam 130 and the second harmonic laser beam 140 are transmitted.

Dichroic mirror 61 is arranged on the optical axis between wavelength conversion crystal 50 and laser medium 20. Dichroic mirror 61 reflects light of a specific wavelength and transmits light of other wavelengths. The dichroic mirror 61 reflects the second harmonic laser beam 140 whose wavelength has been converted by the wavelength conversion crystal 50 toward the wavelength conversion crystal 50 side. The dichroic mirror 61 transmits the laser beam 130 having the fundamental wavelength.

In the first embodiment, the dichroic mirror 61 is a plane mirror in which both surfaces are flat and parallel. For example, a dielectric multilayer antireflection film is formed on the incident surface of the dichroic mirror 61 on the wavelength conversion crystal 50 side, through which the incident laser beam 130 of the fundamental wavelength is transmitted and the second harmonic laser beam 140 is reflected. . On the entrance surface of the dichroic mirror 61 on the laser medium 20 side, for example, a dielectric multilayer antireflection film is formed, through which the incident laser beam 130 of the fundamental wavelength is transmitted.

In the first embodiment, the dichroic mirror 61 is configured to be adjustable in angle with respect to the optical axis. By adjusting the angle of the dichroic mirror 61, it is possible to superimpose the second harmonic laser beam 140 (for example, see FIG. 2) separated by walk-off by the wavelength conversion crystal 50 at a predetermined position. .

Lens 71 is arranged between laser medium 20 and dichroic mirror 61. Although the lens 71 is illustrated as a biconvex lens in the example shown in FIG. 1, it may be a convex lens in the first embodiment.

The combination of the first mirror 31, which is a plane mirror, and the lens 71, which is a convex lens, is equivalent to a concave mirror having the same radius of curvature as the radius of curvature of the concave surface of the second mirror 41. Note that the radius of curvature of the virtual concave mirror formed by the first mirror 31 and the lens 71 is equal to the radius of curvature of the second mirror 41. Thereby, the first mirror 31, the lens 71, and the second mirror 41 constitute a confocal resonator as a whole.

Next, a light focusing state by the solid-state laser oscillator 1 will be explained. FIG. 2 is a schematic diagram showing a focused state of the laser beam 120 oscillated by the solid-state laser oscillator 1 of FIG. FIG. 3 is a schematic diagram showing a focused state of the laser beam 120 oscillated by the solid-state laser oscillator 9 of the comparative example. In the solid-state laser oscillator 9 of the comparative example shown in FIG. 3, the same components as those of the solid-state laser oscillator 1 of the first embodiment shown in FIGS. 1 and 2 are given the same reference numerals, and the description thereof will be omitted. Further, in FIGS. 2 and 3, the laser medium 20 and the second mirror 41 are not shown.

A condensing lens 100 shown in FIG. 2 is provided in a laser processing device equipped with a solid-state laser oscillator 1. Note that in the present invention, the condenser lens 100 may be provided in a solid-state laser oscillator (for example, the solid-state laser oscillator 7 in FIG. 9, which will be described later). In the first embodiment, the condensing lens 100 is a biconvex single lens. The condensing lens 100 condenses the second harmonic laser beam 140 emitted from the first mirror 31 onto a condensing spot 150 .

As shown in FIGS. 2 and 3, compared to the solid-state laser oscillator 1 of the first embodiment, the solid-state laser oscillator 9 of the comparative example includes a first mirror 39 instead of the first mirror 31 and the lens 71. They differ in terms of preparation. The first mirror 39 is a concave mirror that has the same radius of curvature as the radius of curvature of the concave surface of the second mirror 41 (see FIG. 1) on its entrance surface. Thereby, the first mirror 39 and the second mirror 41 constitute a confocal resonator as a whole.

In both the solid-state laser oscillator 1 of the first embodiment and the solid-state laser oscillator 9 of the comparative example, a plurality of second-harmonic laser beams 140 (see FIG. 2 and In FIG. 3, it is separated into two optical axes.

In the solid-state laser oscillator 9 of the comparative example, since the first mirror 39 is a concave mirror, the second harmonic laser beam 140 is emitted in an oblique direction when passing through the first mirror 39. As a result, the intervals between the plurality of optical axes of the second harmonic laser beam 140 widen as they move toward the condenser lens 100. The second harmonic laser beam 140 obliquely enters the condenser lens 100 and is condensed onto a condensing spot 160 . At this time, the focused spot 160 is formed in a distorted shape due to the influence of aberration.

On the other hand, in the solid-state laser oscillator 1 of the first embodiment, since the first mirror 31 is a plane mirror, when the second harmonic laser beam 140 passes through the first mirror 31, it Emit light so that the optical axes are parallel to each other. As a result, the intervals between the plurality of optical axes of the second harmonic laser beam 140 are maintained until the second harmonic laser beam 140 enters the condenser lens 100. The second harmonic laser beam 140 enters the condensing lens 100 in parallel and is condensed on the condensed spot 150, so that the beam image condensed on the condensed spot 150 is the beam image immediately after emission. Distortion can be suppressed. Furthermore, since the angle of the dichroic mirror 61 is adjustable, two beam images that are separated into two can be combined into one at the condensing spot 150.

[Second embodiment]
Next, a solid-state laser oscillator 2 according to a second embodiment will be described based on the drawings. FIG. 4 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 2 according to the second embodiment. In the solid-state laser oscillator 2 of the second embodiment shown in FIG. 4, the same components as those of the solid-state laser oscillator 1 of the first embodiment shown in FIG.

As shown in FIG. 4, compared to the solid-state laser oscillator 1 of the first embodiment, the solid-state laser oscillator 2 of the second embodiment includes a resonator 12 instead of the resonator 11, and further includes a lens 82. They differ in some respects. The resonator 12 is configured by sandwiching the laser medium 20 between a first mirror 31 and a second mirror 42 . That is, the resonator 12 differs from the resonator 11 of the first embodiment in that it includes a second mirror 42 instead of the second mirror 41.

The second mirror 42 of the second embodiment differs from the second mirror 41 of the first embodiment in that it is not a concave mirror but a plane mirror with both surfaces formed of flat surfaces.

Lens 82 is arranged between laser medium 20 and second mirror 42 . Although the lens 82 is illustrated as a biconvex lens in the example shown in FIG. 4, it may be a convex lens in the second embodiment.

The combination of the second mirror 42, which is a plane mirror, and the lens 82, which is a convex lens, is the same as the second mirror 41, which is a concave mirror, in the first embodiment. That is, the combination of the second mirror 42 and the lens 82 is equivalent to a concave mirror having the same radius of curvature as the radius of curvature of the concave surface of the second mirror 41 of the first embodiment. Thereby, the first mirror 31 and lens 71, and the second mirror 42 and lens 82 as a whole constitute a confocal resonator.

[Third embodiment]
Next, a solid-state laser oscillator 3 according to a third embodiment will be described based on the drawings. FIG. 5 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 3 according to the third embodiment. In the solid-state laser oscillator 3 of the third embodiment shown in FIG. 5, the same components as those of the solid-state laser oscillator 1 of the first embodiment shown in FIG.

As shown in FIG. 5, the solid-state laser oscillator 3 of the third embodiment includes a resonator 13 and a lens 73 instead of the resonator 11 and the lens 71, compared to the solid-state laser oscillator 1 of the first embodiment. They differ in some respects. The resonator 13 is configured by sandwiching the laser medium 20 between a first mirror 31 and a second mirror 43. That is, the resonator 13 differs from the resonator 11 of the first embodiment in that it includes a second mirror 43 instead of the second mirror 41.

The second mirror 43 of the third embodiment differs from the second mirror 41 of the first embodiment in that it is not a concave mirror but a convex mirror in which a convex surface is formed on the incident surface.

The lens 73 of the third embodiment differs from the lens 71 of the first embodiment in that it is a concave lens. In the example shown in FIG. 5, the lens 73 is shown as a single-concave lens with a concave surface formed on the surface on the side of the dichroic mirror 61, but in the third embodiment, it may be any concave lens.

The combination of the second mirror 43, which is a convex mirror, and the lens 73, which is a concave lens, is the same as the combination of the second mirror 41, which is a concave mirror, and the lens 71, which is a biconvex lens, in the first embodiment. Thereby, the first mirror 31, the second mirror 43, and the lens 73 collectively constitute a confocal resonator.

[Fourth embodiment]
Next, a solid-state laser oscillator 4 according to a fourth embodiment will be described based on the drawings. FIG. 6 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 4 according to the fourth embodiment. In addition, in the solid-state laser oscillator 4 of the fourth embodiment shown in FIG. 6, the same components as those of the solid-state laser oscillator 1 of the first embodiment shown in FIG.

As shown in FIG. 6, compared to the solid-state laser oscillator 1 of the first embodiment, the solid-state laser oscillator 4 of the fourth embodiment has a resonator 14 and a dichroic mirror 64 instead of the resonator 11 and the dichroic mirror 61. It is different in that it further includes a light shielding member 94. The resonator 14 is configured by sandwiching the laser medium 20 between a first mirror 34 and a second mirror 41. That is, the resonator 14 differs from the resonator 11 of the first embodiment in that it includes a first mirror 34 instead of the first mirror 31.

Compared to the second mirror 41 of the first embodiment, the first mirror 34 of the fourth embodiment is not a mirror in which both surfaces are perpendicular to the optical axis and both surfaces are parallel to each other, but is a mirror that is perpendicular to the optical axis. It differs in that it is a wedge-shaped mirror that has a small angle with respect to the surface and both surfaces are non-parallel.

Compared to the dichroic mirror 61 of the first embodiment, the dichroic mirror 64 of the fourth embodiment is not a mirror in which both surfaces are perpendicular to the optical axis and both surfaces are parallel to each other; The difference is that it is a wedge-shaped dichroic mirror with a small angle and non-parallel surfaces.

In the example shown in FIG. 6, the surface of the first mirror 34 on the wavelength conversion crystal 50 side and the surface of the dichroic mirror 64 on the wavelength conversion crystal 50 side are tilted in the same direction with respect to the plane perpendicular to the optical axis. Although shown in the figure, they may not be the same in the fourth embodiment. Note that the present invention is not limited to the fourth embodiment, and either the first mirror 34 or the dichroic mirror 64 may have a wedge shape. By forming at least one of the first mirror 34 and the dichroic mirror 64 into a wedge shape, it is possible to suppress disruption of laser oscillation due to parasitic oscillation caused by back reflected light entering the laser medium 20.

The light shielding member 94 is arranged between the dichroic mirror 64 and the laser medium 20. The light blocking member 94 blocks a portion of the laser beam 130 having the fundamental wavelength that passes between the dichroic mirror 64 and the laser medium 20 . The light blocking member 94 blocks the return light of the laser beam 130 having the fundamental wavelength from the end face of the dichroic mirror 64. In the fourth embodiment, the light shielding member 94 is an aperture that transmits the laser beam 130 having a fundamental wavelength near the optical axis.

[Fifth embodiment]
Next, a solid-state laser oscillator 5 according to a fifth embodiment will be described based on the drawings. FIG. 7 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 5 according to the fifth embodiment. In addition, in the solid-state laser oscillator 5 of the fifth embodiment shown in FIG. 7, the same components as those of the solid-state laser oscillator 4 of the fourth embodiment shown in FIG.

As shown in FIG. 7, the solid-state laser oscillator 5 of the fifth embodiment differs from the solid-state laser oscillator 4 of the fourth embodiment in that it includes a dichroic mirror 65 instead of the dichroic mirror 64 and lens 71. .

The dichroic mirror 65 of the fifth embodiment differs from the dichroic mirror 64 of the fourth embodiment in that it is not a wedge-shaped plane mirror but a plano-convex mirror in which a convex surface is formed on the surface facing the laser medium 20. different.

The dichroic mirror 65, which is a plano-convex mirror, is equivalent to the combination of the dichroic mirror 64, which is a wedge-shaped plane mirror, and the lens 71, which is a convex lens, in the fourth embodiment.

[Sixth embodiment]
Next, a solid-state laser oscillator 6 according to a sixth embodiment will be described based on the drawings. FIG. 8 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 6 according to the sixth embodiment. In addition, in the solid-state laser oscillator 6 of the sixth embodiment shown in FIG. 8, the same components as those of the solid-state laser oscillator 5 of the fifth embodiment shown in FIG.

As shown in FIG. 8, the solid-state laser oscillator 6 of the sixth embodiment differs from the solid-state laser oscillator 4 of the fourth embodiment in that it includes a dichroic mirror 66 instead of the dichroic mirror 64 and the lens 71. .

The dichroic mirror 66 of the sixth embodiment differs from the dichroic mirror 64 of the fourth embodiment in that it is not a wedge-shaped plane mirror but a plano-concave mirror in which a concave surface is formed on the surface on the wavelength conversion crystal 50 side. It's different.

The dichroic mirror 66, which is a plano-concave mirror, is equivalent to the combination of the dichroic mirror 64, which is a wedge-shaped plane mirror, and the lens 71, which is a convex lens, in the fourth embodiment.

As explained above, the solid-state laser oscillators 1, 2, 3, 4, 5, and 6 according to each embodiment are
In a conventional solid-state laser oscillator, a concave mirror (for example, the first mirror 39 shown in FIG. 3) disposed at the output side end is replaced with a plane mirror (for example, the first mirror 31) and a lens (for example, the lens 71). ), forming a confocal resonator as a whole. Further, the solid-state laser oscillators 1, 2, 3, 4, 5, and 6 have a wavelength conversion crystal 50 and dichroic mirrors 61, 64, 65, and 66 arranged between the plane mirror and the lens.

This prevents the distance between the optical axes separated by the walk-off of the wavelength conversion crystal 50 from further widening due to the effect of the concave mirror as in conventional solid-state laser oscillators, and allows the optical axes to be extracted to the outside without widening the distance between them. Is possible.

Further, by configuring the angles of the dichroic mirrors 61, 64, 65, and 66 to be adjustable, it is possible to superimpose the second harmonic laser beams 140 from two optical axes at the external focal spot 150. Therefore, it is possible to suppress the influence of walk-off caused by the wavelength conversion crystal 50, improve light convergence, and improve processing quality.

In addition, by making the dichroic mirrors 64, 65, and 66 wedge-shaped, plano-convex, or plano-concave, and providing a light shielding member 94, laser oscillation is caused by the back reflected light entering the laser medium 20 and causing parasitic oscillation. It is possible to suppress the destruction of This makes it possible to realize stable laser oscillation.

Note that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the invention. For example, it may further include an optical fiber shown in a first modification example described later or a THG (Third Harmonic Generation) crystal shown in a second modification example.

[First modification]
FIG. 9 is a schematic diagram schematically showing the configuration of the solid-state laser oscillator 7 according to the first modification. The solid-state laser oscillator 7 of the first modified example shown in FIG. 9 differs from the solid-state laser oscillator 1 of the first embodiment shown in FIG. 1 in that it further includes a condenser lens 100 and an optical fiber 110.

A second harmonic laser beam 140 condensed by the condenser lens 100 is incident on the optical fiber 110 . Thereby, the position and angle of the second harmonic laser beam 140 to be transmitted can be freely moved.

[Second modification example]
FIG. 10 is a schematic diagram schematically showing the configuration of a solid-state laser oscillator 8 according to a second modification. The solid-state laser oscillator 8 of the second modification shown in FIG. 10 differs from the solid-state laser oscillator 1 of the first embodiment shown in FIG. 1 in that it further includes a wavelength conversion crystal 58.

The wavelength conversion crystal 58 is a THG crystal that converts the incident laser beam 140 of the second harmonic of the second harmonic into a laser beam of the third harmonic, which is the third harmonic of the laser beam 130 of the fundamental wavelength. It is. In the second modification, the wavelength conversion crystal 58 is movably arranged on the optical axis between the first mirror 31 and the following optical component by a moving mechanism such as a motor.

Thereby, the third harmonic laser beam can be output only when the wavelength conversion crystal 58 is placed on the optical axis. Furthermore, when the wavelength conversion crystal 58 is burnt due to laser beam irradiation, it is possible to use the wavelength conversion crystal 58 continuously by shifting the position of the wavelength conversion crystal 58 little by little using the moving mechanism. be.

In addition, in the above-mentioned first modification and second modification, the optical fiber 110 or the wavelength conversion crystal 58 was provided with respect to the configuration of the first embodiment, but in the present invention, the second to sixth embodiments An optical fiber 110 or a wavelength conversion crystal 58 may be provided for this configuration.

1, 2, 3, 4, 5, 6, 7, 8, 9 solid-state laser oscillator 11, 12, 13, 14 resonator 20 laser medium 31, 34, 39 first mirror 41, 42, 43 second mirror 50, 58 wavelength conversion crystal 61, 64, 65, 66 dichroic mirror 71, 73 lens 82 lens 94 light shielding member 100 condenser lens 110 optical fiber 120 laser beam 130 fundamental wavelength laser beam 140 second harmonic laser beam 150, 160 Focus spot

Claims (7)

a resonator configured by sandwiching a laser medium between a first mirror and a second mirror;
a wavelength conversion crystal that is disposed between the first mirror and the laser medium and converts a fundamental wavelength laser beam oscillated by the laser medium into a second harmonic laser beam;
Disposed between the wavelength conversion crystal and the laser medium, it reflects the second harmonic laser beam wavelength-converted by the wavelength conversion crystal toward the wavelength conversion crystal, and transmits the fundamental wavelength laser beam. A dichroic mirror that
A solid-state laser oscillator comprising:
the first mirror is a plane mirror;
further comprising a lens disposed between the laser medium and the dichroic mirror, the whole forming a confocal resonator;
Solid state laser oscillator. The wavelength conversion crystal is a Type-1 SHG crystal,
The solid-state laser oscillator according to claim 1. At least one of the first mirror and the dichroic mirror is wedge-shaped;
A solid-state laser oscillator according to claim 1 or 2. The method further includes a light shielding member disposed between the dichroic mirror and the laser medium, and shielding light returning from the end face of the dichroic mirror.
The solid-state laser oscillator according to claim 3. a condensing lens that condenses the laser beam;
an optical fiber into which the laser beam focused by the focusing lens enters;
further comprising:
A solid-state laser oscillator according to claim 1 or 2. a resonator configured by sandwiching a laser medium between a first mirror and a second mirror;
a wavelength conversion crystal that is disposed between the first mirror and the laser medium and converts a fundamental wavelength laser beam oscillated by the laser medium into a second harmonic laser beam;
Disposed between the wavelength conversion crystal and the laser medium, it reflects the second harmonic laser beam wavelength-converted by the wavelength conversion crystal toward the wavelength conversion crystal, and transmits the fundamental wavelength laser beam. A dichroic mirror that
A solid-state laser oscillator comprising:
the first mirror is a plane mirror;
The dichroic mirror is a concave mirror or a convex mirror,
Solid state laser oscillator. The dichroic mirror is characterized in that its angle can be adjusted so that the laser beams separated by walk-off by the wavelength conversion crystal are superimposed at a predetermined position.
A solid-state laser oscillator according to any one of claims 1 to 6.

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