JP2001350166A - Method for adjusting optical axis position of laser beam in invisible wavelength region - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easily adjustable the optical axis position of laser beam in an invisible wavelength region. SOLUTION: A fundamental wave laser beam 1 of 1064 nm in wavelength emitted from a YAG laser oscillator 2 is converged by a condenser lens 15, its wavelength is converted into the wavelength of 2nd higher-harmonic laser beam 18 of green of 532 nm in wavelength by a wavelength converting element 16 consisting of non-linear optical crystal, and the 2nd higher-harmonic laser beam 18 are paralled by a collimeter lens 17, then the angles of reflection of bend mirrors 3, 4, 5 and 6 between the YAG laser oscillator 2 and a fiber incidence fiber 10 are adjusted while visualizing the 2nd higher-harmonic laser beam 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the optical axis position of invisible wavelength range laser light.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional method for adjusting the optical axis position of invisible wavelength laser light. A high-power laser generator to which the method is applied oscillates a fundamental laser light 1 having a wavelength of 1064 nm. A YAG laser oscillator 2 and the YAG laser oscillator 2
A first bend mirror 3, a second bend mirror 4, a third bend mirror 5, and a fourth bend mirror 6 arranged so as to sequentially reflect the fundamental wave laser light 1 emitted from the laser oscillator 2, A shutter mirror 7 disposed between the first bend mirror 3 and the second bend mirror 4;
He-Ne oscillating guide laser beam 8 of 32.8 nm
And a laser oscillator 9.

[0003] Each of the bend mirrors 3, 4, 5, and 6 can adjust the reflection angle.

Further, the fundamental laser light 1 reflected by the fourth bend mirror 6 enters an optical fiber (not shown) via a fiber incident lens 10 and a fiber sleeve 11, and is guided to a light irradiation target. .

The shutter mirror 7 emits the fundamental wave laser beam 1 reflected by the first bend mirror 3 toward the second bend mirror 4 or the fundamental wave laser beam reflected by the first bend mirror 3. 1 is selectively set so as to be emitted toward the beam damper 12.

The guide laser light 8 emitted from the He-Ne laser oscillator 9 is reflected by the emission mirror 13, passes through the second bend mirror 4, and enters the third bend mirror 5.

In the high-power laser generator shown in FIG. 2, when adjusting the optical axis position of the fundamental laser beam 1,
The position of the shutter mirror 7 is set so as not to hinder the incidence of the fundamental laser beam 1 from the first bend mirror 3 to the second bend mirror 4, and the position of the fourth bend mirror 6 and the fiber incident lens 10 The shielding plate 14 is arranged between them.

Next, the He-Ne laser oscillator 9 is operated to emit a visible red guide laser beam 8 having a wavelength of 632.8 nm to the output mirror 13, the bend mirrors 4, 5, and 5.
The guide laser beam 8 is guided to the shield plate 14 via the guide plate 6 and a mark is formed at the incident position of the guide laser beam 8 with respect to the shield plate 14.

Further, the YAG laser oscillator 2 is operated alternately with the He-Ne laser oscillator 9 to output the low-power fundamental laser light 1 whose output is about the threshold value and does not exceed 20 W at the maximum, and the bend mirror 3, Shielding plate 1 via 4, 5, 6
4, the reflection angle of the second bend mirror 4 is adjusted while confirming the incident position of the fundamental laser light 1 on the shielding plate 14 by an infrared light visualizing device such as an infrared camera, and the fundamental laser light 1 is adjusted. Is made to coincide with the above-mentioned marking.

As a result, the optical axes of the fundamental wave laser beam 1 and the guide laser beam 8 coincide with each other on the downstream side of the second bend mirror 4, and the guide laser beam 8 is emitted from the He-Ne laser oscillator 9. By doing so, the optical axis position of the fundamental wave laser light 1 becomes visible.

Incidentally, originally, the first bend mirror 3
It is necessary to match the optical axes of the fundamental laser light 1 and the guide laser light 8 emitted from the second bend mirror 4 by adjusting the reflection angle of the second bend mirror 4. Since the deviation of the optical axis of 8 is very small,
To simplify the operation, the adjustment of the reflection angle of the first bend mirror 3 is omitted.

[0012]

However, when the YAG laser oscillator 2 emits the high-power fundamental laser light 1 after the optical axis position adjustment, the heat generated by the laser rod and the bend mirrors 3, 4, 5, and 6 can be reduced. Due to the distortion, the optical axis position of the fundamental laser beam 1 is likely to shift, and the optical axis position may need to be readjusted.

Further, the fundamental laser beam having a large output has a large luminous flux diameter and a non-circular luminous flux cross section, so that it is not easy to determine the center of the optical axis. Therefore, the fundamental laser light 1 and the guide laser It was difficult to ensure the accuracy of coaxializing the light 8.

The present invention has been made in view of the above circumstances, and has as its object to enable easy adjustment of the optical axis position of invisible wavelength region laser light.

[0015]

According to a first aspect of the present invention, there is provided a method for adjusting an optical axis position of a laser beam in an invisible wavelength region, comprising the steps of: The light is converted into a visible wavelength region by a wavelength conversion element, and the reflection angle of a mirror disposed between the laser oscillator and the laser light incident target is adjusted.

In the method of adjusting the optical axis position of invisible wavelength region laser light according to a second aspect of the present invention, the wavelength of laser light emitted from a laser oscillator is converted into a visible wavelength region by a wavelength conversion element. The laser light in the wavelength region is collimated by a collimator lens, and the reflection angle of a mirror disposed between the laser oscillator and the laser light incident target is adjusted.

According to a third aspect of the present invention, in the method for adjusting the optical axis position of laser light in the invisible wavelength region, laser light emitted from a laser oscillator is condensed by a condensing lens and the wavelength is converted by a wavelength conversion element. The laser light in the visible wavelength region is converted into a visible wavelength region, and the laser light in the visible wavelength region is collimated by a collimating lens to adjust the reflection angle of a mirror disposed between the laser oscillator and the laser light incident target.

In any one of the first to third aspects of the present invention, the invisible wavelength region laser light emitted from the laser oscillator is visualized by the wavelength conversion element. This facilitates the adjustment of the reflection angle of the mirror disposed between the laser oscillator and the laser light incident target.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a method for adjusting the optical axis position of laser light in the invisible wavelength region according to the present invention. A laser oscillator 2 and the YAG
A first bend mirror 3, a second bend mirror 4, a third bend mirror 5, and a fourth bend mirror 6 arranged so as to sequentially reflect the fundamental wave laser light 1 emitted from the laser oscillator 2, A shutter mirror 7 disposed between the first bend mirror 3 and the second bend mirror 4;
The fundamental laser light 1 emitted by the fourth bend mirror 6 is transmitted to the fiber incident lens 10 and the fiber sleeve 1.
1 and an optical fiber (not shown) to guide the object to a light irradiation target.

In the high-power laser generator shown in FIG. 1, when adjusting the optical axis position of the fundamental laser beam 1,
The position of the shutter mirror 7 is set so as not to hinder the incidence of the fundamental laser beam 1 from the first bend mirror 3 to the second bend mirror 4, and the position of the fourth bend mirror 6 and the fiber incident lens 10 The condenser lens 15, the wavelength conversion element 16, and the collimator lens 17 are arranged between them.

The following nonlinear optical crystal is used for the wavelength conversion element 16. Nickname Compositional Formula BBO β-BaB ₂ O ₄ KTP KTiOPO ₄ KDP KH ₂ PO ₄ LBO LiB ₃ O ₅ LN LiNbO ₃ KN KNbO ₃

These nonlinear optical crystals generate the second harmonic laser light of wavelength λ ₂ from the incident laser light of wavelength λ _{1 in} the relationship shown by the following equation.

[0024]

## EQU1 ## (1 / λ ₁ ) + (1 / λ ₁ ) = (1 / λ ₂ )

Accordingly, the fundamental laser light 1 in the invisible wavelength region with a wavelength of 1064 nm emitted from the YAG laser oscillator 2 passes through the bend mirrors 3, 4, 5, and 6, and is condensed by the condensing lens 15; The wavelength is converted to a visible second harmonic laser beam 18 having a wavelength of 532 nm by a wavelength conversion element 16 using a non-linear optical crystal, and further collimated by a collimator lens 17.

While visually confirming the second harmonic laser beam 18, the reflection angle of the second bend mirror 4 and the like is adjusted so that the second harmonic laser beam 18 is optimally incident on the fiber incident lens 10. After making appropriate adjustments, the condenser lens 15, the wavelength conversion element 16, and the collimator lens 17
Is removed from between the fourth bend mirror 6 and the fiber incident lens 10.

As described above, in the method of adjusting the optical axis position of the invisible wavelength region laser light shown in FIG. 1, the fundamental wave laser light 1 in the near infrared region emitted from the YAG laser oscillator 2 is used.
Is converted into green second harmonic laser light 18 by a wavelength conversion element 16 using a nonlinear optical crystal, so that the bend mirrors 3, 4, 4 disposed between the YAG laser oscillator 2 and the fiber incident lens 10 are converted. Adjustment of the reflection angles of 5 and 6 can be easily performed.

The method of adjusting the optical axis position of invisible wavelength region laser light according to the present invention is not limited to the above-described embodiment. In order to obtain efficiency, it may not be necessary to use a condensing lens in some cases. Also, it may not be necessary to use a collimating lens. The present invention relates to an invisible wavelength region laser light source other than a YAG laser oscillator. It goes without saying that other modifications can be made without departing from the scope of the present invention.

[0029]

As described above, according to the method of adjusting the optical axis position of the invisible wavelength region laser light of the present invention, the invisible wavelength region laser light emitted from the laser oscillator is visualized by the wavelength conversion element. There is an excellent effect that the reflection angle of the mirror disposed between the laser oscillator and the laser light incident target can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a method for adjusting the optical axis position of invisible wavelength laser light according to the present invention.

FIG. 2 is a conceptual diagram showing an example of a conventional optical axis position adjusting method for invisible wavelength region laser light.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fundamental-wave laser light 2 YAG laser oscillator 3 1st bend mirror 4 2nd bend mirror 5 3rd bend mirror 6 4th bend mirror 10 Fiber incidence lens (laser beam incidence target) 15 Condensing lens 16 wavelength Conversion element 17 Collimating lens 18 Second harmonic laser light

Continued on the front page (72) Inventor Akihiro Nishimi 3-1-1, Toyosu, Koto-ku, Tokyo Ishikawajima-Harima Heavy Industries Co., Ltd. Tokyo Engineering Center (72) Inventor Kenya Nakajima 3-1-1, Toyosu, Koto-ku, Tokyo No. Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Yoshihisa Yamauchi 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center F-term (reference) 2K002 AA04 AB12 CA02 CA03 CA04 GA10 HA20 4E068 CA05 CB05 CD05 CD12

Claims (3)

[Claims] 1. A wavelength conversion device converts a wavelength of a laser beam emitted from a laser oscillator into a visible wavelength region,
An optical axis position adjusting method for invisible wavelength region laser light, comprising adjusting a reflection angle of a mirror disposed between a laser oscillator and a laser light incident target. 2. The wavelength of a laser beam emitted from a laser oscillator is converted into a visible wavelength region by a wavelength conversion element, the laser beam in the visible wavelength region is collimated by a collimating lens, and the laser beam enters the laser oscillator. A method for adjusting an optical axis position of invisible wavelength region laser light, comprising adjusting a reflection angle of a mirror disposed between the mirror and an object. 3. A laser beam emitted from a laser oscillator is condensed by a condenser lens and its wavelength is converted into a visible wavelength region by a wavelength conversion element, and the laser beam in the visible wavelength region is parallelized by a collimator lens. And adjusting a reflection angle of a mirror disposed between the laser oscillator and the laser light incident target.