JP4240763B2 - Laser equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser apparatus.
[0002]
[Prior art]
A laser device in which a resonator and an amplifier are arranged in series is generally used in applications where energy efficiency is not considered as important, such as pulse amplification. Therefore, the laser beam mode (laser beam mode) is controlled on the amplifier side. In order to achieve this, the diameter of the small hole in the aperture (laser beam mode adjusting mechanism) on the amplifier side is provided with an allowance, or unnecessary components are positively removed from the laser beam.
[0003]
Thus, in the case of the laser device described above, the mechanical accuracy such as the manufacturing accuracy and installation accuracy of the device may not be so high, but the energy efficiency of the output laser light is poor and is not suitable as a high-power laser device. Is appropriate. Further, when used as a high-power laser device, there is a problem that if the diameter (molding amount) of the laser beam is not managed well, the optical axis of the laser beam is deviated from a predetermined position and heat is generated.
[0004]
As a high-power laser device, there is one using a multistage YAG laser and arranging a resonator and an amplifier in series. In this case, in order to increase the energy efficiency of the laser light as the output light, it is necessary to reduce the laser light to a desired diameter in order to make the cross-sectional shape of the laser light a desired shape. For this reason, in any of the resonators and amplifiers of conventional high-power laser devices, an aperture is provided as a laser beam mode adjustment mechanism on the laser beam entrance side and exit side of the cavity housing the YAG rod as the laser medium, I try to squeeze the light.
[0005]
FIG. 3 shows an example of a conventional high-power laser device in which a resonator and an amplifier are arranged in series and an aperture is provided as a laser beam mode adjusting mechanism on the laser beam input side and output side of each cavity. . In the figure, 1 is a laser device, 2 is a resonator for generating and resonating laser light 3, and 4 is an amplifier arranged in series downstream of the resonator 2 in the traveling direction of the laser light 3.
[0006]
The resonator 2 includes, for example, an optical surface plate 5, a base 6 that is processed on the optical surface plate 5 with high accuracy in dimensions and levelness, and a laser beam 3 traveling direction entrance side and exit side of the base 6. A pair of resonance laser mirrors 7 and 8 disposed on the upper surface of the end portion, and a YAG rod disposed inside the laser mirrors 7 and 8 so as to be positioned linearly and continuously with respect to the upper surface of the base 6. A plurality of cavities 10 in which 9 is positioned and accommodated, and a small hole 11 such as a pinhole through which the laser light 3 can be passed, are provided at the entrance and exit sides of the laser light 3 of each cavity 10. A thin plate-shaped aperture 12 is provided (see FIG. 4).
[0007]
The amplifier 4 does not include the laser mirrors 7 and 8 as in the resonator 2, but the configuration of other parts is the same as that of the resonator 2. That is, the amplifier 4 is, for example, linearly and continuously positioned on the optical surface plate 13, a base 14 that is processed on the optical surface plate 13 with high accuracy in dimensions and horizontality, and the base 14. A plurality of cavities 16 in which the YAG rods 15 are positioned and housed are installed, and the laser beams 3 are installed on the entrance side and the exit side of each cavity 16 and the laser beam 3 can pass through the center. A thin plate-shaped aperture 18 having a small hole 17 such as a pinhole is provided (see FIG. 4).
[0008]
In the resonator 2 and the amplifier 4, the axial centers of optical elements such as the YAG rods 9 and 15 in the predetermined cavities 10 and 16 and the small holes 11 and 18 in the apertures 12 and 18 that form a pair with the YAG rods 9 and 15. The center of the shaft 17 is adjusted in advance so as to coincide with each other before being set on the bases 6 and 14, and the cavities 10 and 16 and the apertures 12 and 18 are set in the bases 6 and 14 in the state of X -Y can be adjusted in the biaxial direction (where X is the height direction and Y is the radial direction of the YAG rods 9 and 15 in plan view). Although not shown, the YAG rods 9 and 15 are supported by the rod holder, and an O-ring is interposed between the rod holder inner periphery and the YAG rods 9 and 15 outer periphery.
[0009]
Thus, the axes of the optical elements such as the YAG rods 9 and 15 in the resonator 2 and the amplifier 4 of the laser apparatus 1 described above are adjusted in advance so as to coincide with the optical axis of the laser light 3. As an optical element, there are a lens, an optical fiber and the like in addition to the YAG rods 9 and 15.
[0010]
During operation of the laser device 1, the laser light 3 generated by irradiating the YAG rod 9 with an excitation light source (not shown) provided in each cavity 10 of the resonator 2 is resonated between the laser mirrors 7 and 8. , Becomes high level, passes through the laser mirror 8, is output from the resonator 2, and is introduced into the amplifier 4.
[0011]
The laser beam 3 introduced into the amplifier 4 is amplified after passing through a YAG rod 15 irradiated by an excitation light source (not shown) provided in the cavity 16 and is provided downstream. It is introduced into the optical fiber and transmitted to the processing target part.
[0012]
When the laser beam 3 is introduced into or extracted from the YAG rods 9 and 15 provided in the cavities 10 and 16 of the resonator 2 and the amplifier 4, the laser beam 3 is small in the apertures 12 and 18. Pass through holes 11 and 17. For this reason, as shown in FIG. 4, the laser beam 3 changes its diameter due to the thermal lens effect of the YAG rods 9 and 15 when passing through the YAG rods 9 and 15, but the small holes 11 of the apertures 12 and 18. , 17 and the optical axis is reduced to a predetermined position with respect to the axis of the optical element.
[0013]
Therefore, in the resonator 2, the laser beam mode of the laser beam 3 is controlled so that the transmittance of the laser mirror 8 is optimized, and in the amplifier 4, the beam mode of the laser beam 3 is controlled so that the output is maximized. The As a result, the laser device 3 outputs a laser beam 3 with high output and high energy efficiency.
[0014]
[Problems to be solved by the invention]
In the laser apparatus described above, in order to increase the energy efficiency, the effective medium cross-sectional areas of the resonator 2 and the amplifier 4 in the YAG rods 9 and 15 may be made the same. For this purpose, the resonator 2 and the amplifier 4 are used. It is necessary to set the axis line with high machine accuracy. This must be fairly high accuracy, and when the device is manufactured with practical mechanical accuracy (for example, 2/1000 mm), the effective diameters of the small holes 11 and 17 in the apertures 12 and 18 of the resonator 2 and the amplifier 4 are reduced. If they are the same, the optical axis of the laser beam 3 in the amplifier 4 is slightly shifted from the axis of the YAG rod 15 in the amplifier 4, and the problem of abnormal heat generation due to the thermal lens effect of the YAG rod 15 is inevitable.
[0015]
On the other hand, when the aperture 18 is not provided on the amplifier 4 side, the risk of the disturbance of the optical axis of the laser beam 3 cannot be avoided. This increases the risk of damage, and may cause abnormal heat generation in a transmission optical system such as an optical fiber.
[0016]
The present invention is made by paying attention to the characteristic that the laser beam mode is determined in the resonator and the amplifier side simply amplifies the laser beam mode. If the position of the optical axis of the laser beam is not precisely controlled by the amplifier, it is possible to prevent abnormal heat generation in the device. It is also intended to suppress beam mode disturbances that may occur in the amplifier.
[0017]
The laser apparatus of the present invention includes a resonator that generates and resonates laser light, and an amplifier that is arranged in series with the resonator and amplifies the laser light from the resonator,
Resonator includes a pair of laser mirrors for resonance to the traveling direction of the laser beam are arranged at predetermined intervals, is Rezaro' de inside while being disposed between the pair of laser mirrors housed A cavity, and a first laser beam mode adjustment mechanism having a small hole provided on at least one of the inlet side and the outlet side of the cavity,
Amplifier includes a cavity Rezaro' de therein is housed, and a second laser beam mode adjusting mechanism having an inlet side and the small hole provided on at least one of the outlet side of said cavity,
The diameter of the small hole of the second laser beam mode adjusting mechanism is set to the first amount by the predicted amount of the laser beam deviation caused by the transmission of the laser beam outputted from the resonator to the amplifier side and the position deviation amount of the amplifier itself . This is larger than the diameter of the small hole of the laser beam mode adjusting mechanism.
[0019]
In the present invention, when the laser beam passes through the small hole in the laser beam mode adjustment mechanism of the amplifier, it is not cut off excessively in the laser beam mode adjustment mechanism, and the optical axis control in the amplifier is rough, so that the amplifier Even if the optical axis position of the laser beam becomes abnormal after being output from the laser, it is possible to prevent heat generation in the amplifier, and furthermore, it is possible to manage the laser light in the amplifier without difficulty and to avoid heat generation. However, since the position of the optical axis with respect to the amplifier can be adjusted with appropriate accuracy, the disturbance of the laser beam mode caused by the amplifier can also be controlled, and furthermore, the laser beam can be controlled by suppressing the disturbance of the optical axis of the laser light. Can easily pass through the amplifier while maintaining the beam characteristics in the resonator, thus further improving energy efficiency. Multiplication effect can be expected.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described together with illustrated examples.
[0021]
1 and 2 show an example of an embodiment for carrying out the present invention, and the laser apparatus 1 itself has the same configuration as that shown in FIG. 3, but the feature of this illustrated example is that shown in FIGS. As shown, the diameter D2 of the small hole 17 in the aperture 18 of the amplifier 4 is made larger than the diameter D1 of the small hole 11 in the aperture 12 of the resonator 2.
[0022]
That is, the diameter D1 of the small hole 11 in the aperture 12 is the same as that of the conventional case shown in FIG. 4, but the diameter D2 of the small hole 17 in the aperture 18 is more shifted by mechanical accuracy than the diameter D1 of the small hole 11. It is formed slightly larger as much as it allows.
[0023]
Specifically, in the resonator 2, the diameter of the laser beam 3 between the aperture 12 on the downstream side of one cavity 10 and the aperture 12 on the upstream side of another adjacent cavity 10 is 3.0 mm. Then, since the laser beam 3 is slightly expanded at the position of the small hole 11, the diameter D1 of the small hole 11 is set to 3.2 mm.
[0024]
In the amplifier 4, the diameter D <b> 2 of the small hole 17 of the aperture 18 is slightly larger than the small hole 11 and is about 3.4 mm. This is because the predicted amount of deviation of the laser beam 3 caused by transmission of the laser beam 3 output from the resonator 2 to the amplifier 4 side and the amount of positional deviation of the amplifier 4 itself is ± 0.1 mm. Because.
[0025]
As described above, when the diameter D2 of the small hole 17 in the aperture 18 is slightly larger than the diameter D1 of the small hole 11 in the aperture 12, the laser light 3 passes through the small hole 17 in the aperture 18 of the amplifier 4. Since the aperture 18 is not cut off excessively by interfering with the edge of the small hole 17, and the optical axis control in the amplifier 4 is rough, the optical axis position of the laser beam 3 after the output from the amplifier 4 is abnormal. Even in this case, heat generation in the amplifier 4 can be prevented.
[0026]
Furthermore, since the laser beam 3 can be managed without difficulty in the amplifier 4 and the position of the optical axis with respect to the amplifier 4 can be adjusted with appropriate accuracy while avoiding heat generation, the laser beam mode disturbance caused by the amplifier 4 can be prevented. In this way, by suppressing the disturbance of the optical axis of the laser beam 3, the laser beam 3 can easily pass through the amplifier 4 while maintaining the beam characteristics in the resonator 2. Therefore, a synergistic effect that energy efficiency is further improved can be expected.
[0027]
Note that the laser apparatus of the present invention is not limited to the above-described illustrated examples, and it is needless to say that various modifications can be made without departing from the scope of the present invention.
[0028]
【The invention's effect】
Above, in the laser apparatus of the serial placement in claim 1 of the present invention as described, the diameter of the small holes in the laser beam mode adjusting mechanism of the amplifier, the transmission to the amplifier side of the laser beam outputted from the resonator only the predicted amount of deviation amount of the resulting laser beam and the positional deviation amount of the amplifier itself, by greatly than the diameter of the small holes in the laser beam mode adjusting mechanism of the resonator,
I) When the laser beam passes through the small hole in the laser beam mode adjusting mechanism of the amplifier, it is not cut off excessively in the laser beam mode adjusting mechanism.
II) Since the optical axis control in the amplifier is rough, even when the optical axis position of the laser beam becomes abnormal after output from the amplifier, it is possible to prevent heat generation in the amplifier.
III) The laser beam in the amplifier can be managed without difficulty, and the position of the optical axis with respect to the amplifier can be adjusted with appropriate accuracy while avoiding heat generation, so that the beam mode disturbance caused by the amplifier can also be controlled. it can,
IV) By suppressing the disturbance of the optical axis of the laser beam, the laser beam can easily pass through the amplifier while maintaining the beam characteristics in the resonator, and therefore a synergistic effect is expected to further improve the energy efficiency. it can,
Various excellent effects can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an outline of an aperture in a resonator used in a laser apparatus of the present invention.
FIG. 2 is a sectional view showing an outline of an aperture in an amplifier used in the laser apparatus of the present invention.
FIG. 3 is a layout diagram for explaining an outline of a laser device.
FIG. 4 is an enlarged view of a portion of a YAG rod and an aperture used for a resonator and an amplifier.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser oscillation apparatus 2 Resonator 3 Laser beam 4 Amplifier 7 Laser mirror 8 Laser mirror 9 YAG rod (laser rod)
10 Cavity 11 Small hole 12 Aperture (Laser beam mode adjustment mechanism)
15 YAG rod (laser rod)
16 Cavity 17 Small hole 18 Aperture (Laser beam mode adjustment mechanism)
D1 diameter D2 diameter

Claims (1)

A resonator that generates and resonates laser light, and an amplifier that is arranged in series with the resonator and amplifies the laser light from the resonator;
Resonator includes a pair of laser mirrors for resonance to the traveling direction of the laser beam are arranged at predetermined intervals, is Rezaro' de inside while being disposed between the pair of laser mirrors housed A cavity, and a first laser beam mode adjustment mechanism having a small hole provided on at least one of the inlet side and the outlet side of the cavity,
Amplifier includes a cavity Rezaro' de therein is housed, and a second laser beam mode adjusting mechanism having an inlet side and the small hole provided on at least one of the outlet side of said cavity,
The diameter of the small hole of the second laser beam mode adjusting mechanism is set to the first amount by the predicted amount of the laser beam deviation caused by the transmission of the laser beam outputted from the resonator to the amplifier side and the position deviation amount of the amplifier itself . A laser device characterized in that it is larger than the diameter of the small hole of the laser beam mode adjusting mechanism.

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