JP2012253099A - Laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser device which can stabilize amplified light output.SOLUTION: A present laser device comprises a first excitation semiconductor laser 22 having reference laser output capable of exciting a rare earth doped optical fiber 21 to a high excited state and a second excitation semiconductor laser 23 having laser output lower than that of the first excitation semiconductor laser 22. Before laser beams are pulse oscillated from a signal semiconductor laser 10, the rare earth doped optical fiber 21 is preliminarily excited by laser beams radiated from the second excitation semiconductor laser 23. When laser beams are radiated from the signal semiconductor laser 10, the rare earth doped optical fiber 21 is excited by laser beams radiated from the first excitation semiconductor laser 22. In the present laser device, at a start of radiation of laser beams from the first excitation semiconductor laser 22, the laser output is lowered to the reference laser output after the laser output is set at a high laser output higher than the reference laser output.

Description

  The present invention relates to a laser device that amplifies laser light emitted from a signal laser light source through an optical amplification unit and emits the amplified light as amplified light.

  As this type of laser apparatus, for example, a laser processing apparatus that performs marking on an object to be processed by laser light irradiation has been put into practical use. In this apparatus, laser light is pulse-oscillated from the signal semiconductor laser, and this laser light is incident on a rare earth-doped optical fiber that functions as an optical amplifier. The rare earth-doped optical fiber is excited in a highly excited state by laser light emitted from an excitation semiconductor laser. Therefore, the laser light incident on the rare earth doped optical fiber from the signal semiconductor laser is amplified when passing through the rare earth doped optical fiber, and is emitted as amplified light from the emission end face. The amplified light is condensed on the work through the converging lens, and the desired marking is performed by scanning the condensed light thus collected on the surface of the work.

  By the way, in such a laser processing apparatus, when an attempt is made to excite the rare-earth doped optical fiber to a high excitation state at the start of marking, a certain amount of time is required until the excitation is actually performed to the high excitation state. Therefore, there may be a case where sufficient output cannot be obtained with the first pulse of the amplified light emitted from the laser processing apparatus at the start of marking, and the quality of the marking may be deteriorated.

  Therefore, in the conventional laser processing apparatus, for example, as seen in Patent Document 1, a first excitation semiconductor laser having a laser output (reference laser output) capable of exciting a rare earth-doped optical fiber to a high excitation state; A second pumping semiconductor laser having a laser output lower than that of the first pumping semiconductor laser is provided. As shown in FIG. 7, if a switch provided in the laser processing apparatus is turned on at time t10, as shown in FIG. 7B, only the second excitation semiconductor laser is a low laser at that time. Laser light is continuously oscillated at the output Le. As a result, the rare-earth-doped optical fiber is preliminarily excited in a state where marking is impossible by the laser light emitted from the second excitation semiconductor laser. Thereafter, as shown in FIG. 7 (a), the first pumping semiconductor laser continuously oscillates the laser beam with the reference laser output Ld at time t11, and at the same time t11 as shown in FIG. 7 (d). Semiconductor lasers oscillate laser light. At this time, the rare-earth-doped optical fiber that has already been pre-pumped is immediately pumped to the high pumping state by the laser light emitted from the first pumping semiconductor laser. Therefore, as shown in FIG. 7E, a sufficient output Lf can be secured by the first pulse P20 of the amplified light, so that the quality of marking can be improved. FIG. 7C shows the total laser output of the laser light source used for exciting the rare earth-doped optical fiber.

JP 34118852 A

  Thus, if the rare earth doped optical fiber is preliminarily pumped before the laser light is emitted from the signal semiconductor laser, a sufficient output Lf can be secured by the first pulse P20 of the amplified light. It will be possible. However, in the amplification light output measurement experiment by the inventor, it has been confirmed that the output of several pulses after the second pulse 21 is lower than the predetermined output Lf, as shown in FIG. Such a decrease in the output of the amplified light is considered to be mainly due to the following causes.

  ・ Much of the energy stored in the rare-earth doped optical fiber during the pre-excitation is consumed when the first pulse of the laser light emitted from the signal semiconductor laser is amplified, so the initial pulse after the second pulse Cannot be amplified sufficiently.

  Due to the fluorescence lifetime of the rare earth-doped optical fiber, it takes a certain amount of time for the rare-earth-doped optical fiber to transition from the pre-pumped state to the high-pumped state by the laser light emitted from the first pumping semiconductor laser.

  When a high repetition pulse operation is performed in the signal semiconductor laser, the pulse light is incident on the rare earth-doped optical fiber with an extremely short period, so that the energy accumulated in the rare earth doped optical fiber is easily consumed. For this reason, the energy accumulated in the rare earth-doped optical fiber tends to be insufficient, particularly in the excitation transient stage from the pre-excitation state to the high excitation state.

Thus, in such a laser processing apparatus, there is still room for improvement in terms of stabilizing the output of the amplified light.
Such a problem is not limited to a laser processing apparatus that performs processing such as marking, drilling, cutting, and welding on a workpiece by laser light irradiation, but amplifies laser light through an optical amplification unit such as a rare earth doped optical fiber. This is a problem common to various laser devices that emit light.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a laser apparatus capable of stabilizing the output of amplified light.

  In order to solve the above-mentioned problem, the invention according to claim 1 amplifies the laser light pulse-oscillated from the signal laser light source through the optical amplifying unit, and excites the optical amplifying unit when emitted as amplified light. As the excitation laser light source, a first excitation laser light source having a reference laser output and a second excitation laser light source having a laser output lower than that of the first excitation laser light source are provided. Before the laser light is pulse-oscillated, the optical amplification unit is preliminarily excited by the laser light emitted from the second excitation laser light source, and the first laser light is emitted from the signal laser light source. In the laser apparatus that excites the optical amplifying unit with laser light emitted from an excitation laser light source, the first excitation laser light source starts emitting laser light. Preparative to the condition, after setting the laser output of the first pumping laser light source to a high laser output is higher than the reference laser output, and summarized in that which is adapted to lower to the reference laser output.

  According to this configuration, since the laser output of the first excitation laser light source is set to a high laser output with the start of emission of laser light from the first excitation laser light source, the optical amplifying unit is switched to the high excitation state. It is excited strongly with the start of excitation. As a result, the initial pulse of the laser light emitted from the signal laser light source is further amplified, so that a sufficient output can be secured with the initial pulse of the amplified light. Therefore, the output of the amplified light can be stabilized.

  According to a second aspect of the present invention, in the laser device according to the first aspect, the setting of the high laser output in the first excitation laser light source is the start of emission of laser light from the first excitation laser light source. The gist of what is sometimes done.

  According to this configuration, when the first excitation laser light source starts emitting laser light, the laser output is set to a high laser output, so that the excitation of the optical amplification unit to the high excitation state is started. In this case, the optical amplification unit is strongly excited. Thus, the initial pulse of the laser light emitted from the signal laser light source can be more effectively amplified, which is effective in securing a sufficient output with the initial pulse of the amplified light.

  According to a third aspect of the present invention, in the laser device according to the first or second aspect, a decrease in the laser output of the first excitation laser light source from the high laser output to the reference laser output is the same as the laser output. The gist is that it is performed as a gradual reduction process.

  According to this configuration, since the optical amplifying unit can be excited in a manner that compensates for the decrease in the output of the amplified light exemplified in FIG. 7E, the output of the amplified light can be further stabilized. It becomes like this.

  According to a fourth aspect of the present invention, in the laser apparatus according to any one of the first to third aspects, when starting the emission of the laser light from the signal laser light source, the emission of the first pulse is as follows: The gist of the present invention is that it is performed before the laser light is emitted from the first excitation laser light source.

  When the first pulse of the laser light from the signal laser light source is emitted before the laser light is emitted from the first excitation laser light source as in the same configuration, the signal laser light source Since the first pulse of the emitted laser light is amplified by the energy accumulated in the optical amplification unit at the time of preliminary excitation, it is possible to ensure a sufficient output with the first pulse of the amplified light. As a result, amplified light having a sufficient output can be emitted more quickly, and the waiting time of the user can be shortened.

  According to the laser device of the present invention, the output of the amplified light can be stabilized.

The block diagram which shows the schematic structure about one Embodiment of the laser processing apparatus to which the laser apparatus concerning this invention is applied. The flowchart which shows the procedure of the marking process by the laser processing apparatus of the embodiment. (A)-(e) is a timing chart which shows the operation example about the laser processing apparatus of the embodiment. (A)-(e) is a timing chart which shows the operation example about the other example of the laser processing apparatus to which the laser apparatus concerning this invention is applied. (A)-(e) is a timing chart which shows the operation example about the other example of the laser processing apparatus to which the laser apparatus concerning this invention is applied. (A)-(e) is a timing chart which shows the operation example about the other example of the laser processing apparatus to which the laser apparatus concerning this invention is applied. (A)-(e) is a timing chart which shows the operation example about the conventional laser processing apparatus.

  Hereinafter, an embodiment of a laser processing apparatus to which a laser apparatus according to the present invention is applied will be described with reference to FIGS. In addition, the laser processing apparatus concerning this embodiment marks a character, a figure, etc. on a workpiece | work by irradiation of a laser beam. First, with reference to FIG. 1, the outline | summary of the laser processing apparatus concerning this embodiment is demonstrated.

  As shown in FIG. 1, in this laser processing apparatus, when a user inputs a character, a figure, or the like to the input unit 3, the laser beam generated by the laser generation unit 1 is irradiated to the workpiece W via the head unit 2. Characters, figures, etc. are marked on the workpiece W.

  The laser generator 1 includes a signal semiconductor laser 10 as a signal laser light source that pulsates an infrared laser, and an amplifier 20 that amplifies the laser light emitted from the semiconductor laser 10. Laser light emitted from the signal semiconductor laser 10 is input to the amplifier 20 through the optical fiber 26a and amplified, and then amplified as light through an optical fiber 26d provided at the rear end of the amplifier 20. Incident into part 2.

  The amplifier 20 includes, for example, a rare earth-doped optical fiber 21 made of a glass fiber containing yttrium (Yb), which is a rare earth element, and a first pumping semiconductor having a laser output that excites the optical fiber 21 into a highly pumpable state capable of marking. And a laser 22. The amplifier 20 includes a second pumping semiconductor laser 23 having a laser output lower than that of the first pumping semiconductor laser 22. In the present embodiment, the rare earth-doped optical fiber 21 is an optical amplification unit. The first and second pumping semiconductor lasers 22 and 23 serve as the first and second pumping laser light sources.

  The first excitation semiconductor laser 22 makes the laser light incident on the rare earth-doped optical fiber 21 via the optical fiber 26c. The second pumping semiconductor laser 23 makes the laser light incident on the rare earth-doped optical fiber 21 via the optical fiber 26b.

  On the other hand, the rare earth-doped optical fiber 21 has a structure in which an optical path having a required length is secured by being wound many times on a bobbin (not shown). In the drawing, the direction from the incident end 21a to the emission end 21b in the rare earth-doped optical fiber 21 is indicated by an arrow a. First and second optical coupling portions 24 and 25 are provided at the incident end 21a and the emission end 21b of the rare earth-doped optical fiber 21, respectively.

  Laser light emitted from the signal semiconductor laser 10 is incident on the first optical coupling portion 24 via the optical fiber 26a, and laser light emitted from the second excitation semiconductor laser 23 passes through the optical fiber 26b. Through. The first optical coupling unit 24 transmits the laser light emitted from the signal semiconductor laser 10 and the laser light emitted from the second excitation semiconductor laser 23 to the incident end 21a of the rare earth-doped optical fiber 21 in the direction indicated by the arrow a. Respectively. The laser light emitted from the second pumping semiconductor laser 23 is incident on the rare earth-doped optical fiber 21 via the first optical coupling portion 24, so that the rare earth doped optical fiber 21 is low-pumped and cannot be marked. Pre-excited in the state.

  On the other hand, laser light emitted from the emission end 21b of the rare earth-doped optical fiber 21 is incident on the second optical coupling unit 25, and laser light emitted from the first excitation semiconductor laser 22 passes through the optical fiber 26c. Through. The second optical coupling unit 25 causes the laser beam emitted from the first excitation semiconductor laser 22 to enter the emission end 21b of the rare earth-doped optical fiber 21 in the direction opposite to the direction indicated by the arrow a. As a result, the rare earth-doped optical fiber 21 is excited to a highly excited state that can be marked. The second optical coupling unit 25 emits laser light (amplified light) emitted from the emission end 21b of the rare earth-doped optical fiber 21 to the head unit 2 through the optical fiber 26d.

  The optical fiber 26a is provided with an optical isolator 27 that allows laser light to pass only in the direction indicated by the arrow a. That is, the optical isolator 27 prevents the light reflected by the joint portion of the optical fiber and the laser reflecting surface from flowing backward to the signal semiconductor laser 10 and damaging the semiconductor laser 10.

  On the other hand, the head unit 2 includes a collimator lens 40 that narrows the amplified light emitted from the optical fiber 26d of the laser generating unit 1 into parallel light or convergent light. The amplified light focused through the collimator lens 40 is reflected in a required direction by the optical scanning mechanism 41 provided in the head unit 2. The optical scanning mechanism 41 is configured to include two galvanometer mirrors that reflect the amplified light, and the amplified light focused through the collimator lens 40 is required by changing the inclination angle of each galvanometer mirror. Scanning in the direction of. The amplified light reflected by the optical scanning mechanism 41 is narrowed down to a spot laser beam by the condenser lens 42. Then, the narrowed amplified light scans the surface of the workpiece W, whereby desired marking is performed.

  Further, as described above, the input unit 3 is a part where characters, graphics, and the like to be printed on the workpiece W are input, and also a part where operations such as starting and stopping of marking are performed by the user. When a character or graphic is input, the input unit 3 outputs the input information. Further, when a marking start operation and a stop operation are performed, the input unit 3 outputs an operation signal indicating that. Then, the outputs of these input units 3 are taken into a control unit 5 configured mainly with a microcomputer.

  The control unit 5 controls the supply current amounts of the semiconductor lasers 10, 22, and 23 through the drivers 30 to 32 based on the output of the input unit 3, thereby driving, stopping, and lasering the semiconductor lasers 10, 22, and 23, respectively. Control the output. The control unit 5 also controls driving of the optical scanning mechanism 41. Specifically, when input information such as characters or figures to be printed on the workpiece W is transmitted from the input unit 3, the control unit 5 stores the input information in the memory 5a. Thereafter, when it is detected that the marking start operation has been performed based on the operation signal output from the input unit 3, first, the second pumping semiconductor laser 23 is driven via the driver 32, whereby the rare-earth doped optical fiber 21. Are pre-excited for a predetermined time. Thereafter, based on the input information stored in the memory 5a, the signal semiconductor laser 10 and the first pumping semiconductor laser 22 are driven via the drivers 30 and 31, and the optical scanning mechanism 41 is driven, thereby A figure or the like is marked on the workpiece W.

  Next, with reference to FIG. 2, the procedure of the marking process will be described. 2 is executed when it is detected that a marking start operation has been performed based on an operation signal output from the input unit 3. The reference laser output La1 is set based on the output of the amplified light, and indicates a laser output capable of exciting the rare earth-doped optical fiber 21 to a high excitation state capable of marking.

  As shown in FIG. 2, in this process, first, the laser light is continuously oscillated from the second pumping semiconductor laser 23 through the driver 32 with the low laser output Lb (step S1), and the first predetermined time Ta is set. It is monitored whether or not it has elapsed (step S2). The low laser output Lb is set to a value lower than the reference laser output La1 and capable of exciting the rare earth doped optical fiber 21 to a low excitation state where marking is impossible. In addition, the first predetermined time Ta is determined depending on the magnitude of the reference laser output La1, and a preliminary experiment is performed so that a sufficient output can be secured by the first pulse of the amplified light. Etc. are set through. If the first predetermined time Ta has elapsed (step S2: YES), the laser light is pulse-oscillated from the signal semiconductor laser 10 (step S3), and then the first laser light is emitted from the signal semiconductor laser 10. It is monitored whether or not the second predetermined time Tb has elapsed since the pulse was emitted (step S4). The second predetermined time Tb is set to a time shorter than the period from when the first pulse of laser light is emitted in the signal semiconductor laser 10 to when the second pulse is emitted. Then, when the second predetermined time Tb has elapsed since the first pulse of the laser beam was emitted from the signal semiconductor laser 10 (step S4: YES), the high laser output La2 from the first excitation semiconductor laser 22 is obtained. Laser light is continuously oscillated (step S5). Further, in the subsequent step S6, the laser output of the first excitation semiconductor laser 22 is gradually reduced to the reference laser output La1 over a third predetermined time Tc (step S6). Thereafter, it is monitored whether or not the marking is completed (step S7). When the marking is completed (step S7: YES), the oscillation of each of the semiconductor lasers 10, 22, and 23 is stopped (step S8). .

Next, an operation example (action) of the laser processing apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 3, if the user performs a marking start operation on the input unit 3 at time t1, for example, as shown in FIG. 3B, the second excitation semiconductor laser 23 has a low laser output Lb. Laser light is oscillated continuously. Thereby, the rare earth doped optical fiber 21 is excited to a low excitation state incapable of marking. Then, at the time t2 when the first predetermined time Ta has elapsed from the time t1, the rare earth-doped optical fiber 21 is excited to a level at which a sufficient output Lc can be secured with the first pulse of the amplified light. In the laser processing apparatus of the present embodiment, as shown in FIG. 3D, the signal semiconductor laser 10 starts pulse oscillation of the laser light at time t2. At this time, the first pulse P10 of the laser light emitted from the signal semiconductor laser 10 is amplified by the energy accumulated in the rare earth-doped optical fiber 21 at the time of the preliminary excitation, and as shown in FIG. In addition, a sufficient output Lc can be secured by the first pulse P1 of the amplified light.

  Further, at the time t3 when the second predetermined time Tb has elapsed from the time when the first pulse P10 of the laser beam is emitted from the signal semiconductor laser 10, that is, from the emission of the first pulse P10 of the semiconductor laser 10 to the second time. Before the emission of the pulse P11, as shown in FIG. 3A, the first excitation semiconductor laser 22 continuously oscillates the laser beam with the high laser output La2. Thereby, the rare earth doped optical fiber 21 is excited to a highly excited state from time t3. Then, during the period from time t3 to t4 when the third predetermined time Tc has elapsed, the laser output of the first excitation semiconductor laser 22 gradually decreases from the high laser output La2 to the reference laser output La1, and then held at the reference laser output La1. Is done. At this time, as shown in FIG. 3C, the total laser output of the pumping light source becomes particularly strong at time t3, so that the rare earth-doped optical fiber 21 is pumped particularly strongly at the start of pumping to the high pumping state. . For this reason, the initial pulse after the second pulse P11 of the laser light emitted from the signal semiconductor laser 10 can be further amplified. Further, if the laser output of the first pumping semiconductor laser 22 is gradually decreased from the high laser output La2 to the reference laser output La1, the decrease in the output of the amplified light illustrated in FIG. The rare earth-doped optical fiber 21 can also be excited in the form. Therefore, as shown in FIG. 3E, a sufficient output Lc can be ensured even with the initial pulse after the second pulse P2 of the amplified light, so that the output of the amplified light can be stabilized.

If the marking is completed at time t5 thereafter, the oscillation of each of the semiconductor lasers 10, 22, and 23 is stopped at that time, as shown in FIGS. 3 (a), (b), and (d).
As described above, according to the laser processing apparatus according to the present embodiment, the following effects can be obtained.

  (1) At the start of emission of laser light from the first excitation semiconductor laser 22, the laser output is set to a high laser output La2 higher than the reference laser output La1, and then lowered to the reference laser output La1. As a result, a sufficient output can be ensured by the initial pulse of the amplified light, so that the output of the amplified light can be stabilized.

  (2) In reducing the laser output of the first excitation semiconductor laser 22 from the high laser output La2 to the reference laser output La1, the laser output is gradually reduced. This makes it possible to excite the rare earth-doped optical fiber 21 in a manner that compensates for the decrease in the output of the amplified light excited in FIG. 7E, so that the output of the amplified light can be further stabilized. become.

  (3) When starting emission of the laser light from the signal semiconductor laser 10, the first pulse is emitted before the laser light is emitted from the first excitation semiconductor laser 22. As a result, the amplified light having a sufficient laser output can be emitted earlier, so that the waiting time of the user can be shortened.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
As a method for reducing the laser output of the first pumping semiconductor laser 22 from the high laser output La2 to the reference laser output La1, for example, a method as shown in FIGS. 4 and 5 may be employed. That is, as shown in FIG. 4A, the laser output of the first excitation semiconductor laser 22 may be changed in pulses. Further, as shown in FIG. 5A, the laser output of the first excitation semiconductor laser 22 may be changed stepwise. Even with such a configuration, since the initial pulse of the laser light emitted from the signal laser light source can be further amplified, it is possible to stabilize the output with high amplification.

  As a method for reducing the laser output of the first excitation semiconductor laser 22 from the high laser output La2 to the reference laser output La1, for example, a method as shown in FIG. 6 may be employed. That is, as shown in FIG. 6A, when emission of laser light from the first excitation semiconductor laser 22 is started at time t3, the laser output is temporarily set to the reference laser output La1. Then, at the time t6 when the predetermined time Td has elapsed from the time t3, the laser output of the first excitation semiconductor laser 22 is set to the high laser output La2 and gradually decreased from that time to the reference laser output La1. In such a configuration, when the method of the above embodiment, that is, the method of setting the laser output to the high laser output La2 at the start of the emission of the laser light from the first excitation semiconductor laser 22, the amplified light is used. This is effective when the output of the first pulse or the second pulse becomes too large.

  The timing for starting the emission of the laser beam from the signal semiconductor laser 10 may be set when the laser beam is emitted from the first excitation semiconductor laser 22 with the high laser output La2 or after that.

  In the above embodiment, the laser processing apparatus according to the present invention is applied to a laser processing apparatus including two excitation semiconductor lasers. For example, the laser processing apparatus is applied to a laser processing apparatus including three or more excitation semiconductor lasers. It is also possible to do.

  In the above embodiment, the laser apparatus according to the present invention is applied to a laser processing apparatus (laser marker) that marks a workpiece. For example, laser processing that performs processing such as drilling, cutting, and welding on a workpiece. It is also possible to apply to an apparatus. Further, the present invention is not limited to the laser processing apparatus, and can be applied to various laser apparatuses that amplify and emit laser light through an optical amplification unit such as the rare earth doped optical fiber 21.

<Appendix>
Next, a technical idea that can be grasped from the above embodiment and its modifications will be additionally described.
(A) In a laser processing apparatus for processing the object to be processed by irradiating the object to be processed with a laser beam, as an apparatus for irradiating the object to be processed with the laser light, any one of claims 1 to 4. The laser processing apparatus characterized by the above-mentioned is used. As described above, in the laser processing apparatus, in order to increase the processing accuracy, stabilization of the output of the amplified light is strongly desired. Therefore, it is significant to use the laser apparatus described above for such a laser processing apparatus.

  W ... Work, 1 ... Laser generator, 2 ... Head, 3 ... Input, 5 ... Control, 5a ... Memory, 10 ... Signal semiconductor laser, 20 ... Amplifier, 21 ... Rare earth doped optical fiber, 21a ... Incident End, 21b ... Output end, 22 ... First excitation semiconductor laser, 23 ... Second excitation semiconductor laser, 24 ... First optical coupling portion, 25 ... Second optical coupling portion, 26a-26d, Optical fiber, 27 ... Optical isolators, 30 to 32... Drivers, 40... Collimator lenses, 41.

Claims (4)

A first pumping laser light source having a reference laser output as a pumping laser light source for exciting the light amplifying unit when the laser light pulse-oscillated from the signal laser light source is amplified through an optical amplifying unit and emitted as amplified light And a second excitation laser light source having a laser output lower than that of the first excitation laser light source, before pulsing the laser light from the signal laser light source, from the second excitation laser light source. The optical amplifying unit is preliminarily excited by the emitted laser light, and when the laser light is emitted from the signal laser light source, the optical amplifying unit is excited by the laser light emitted from the first excitation laser light source. In the laser device to be
On condition that the first excitation laser light source starts emitting laser light, the laser output of the first excitation laser light source is set to a high laser output higher than the reference laser output, and then the reference laser output A laser device characterized by being lowered to a minimum. The laser apparatus according to claim 1, wherein the setting of the high laser output in the first excitation laser light source is performed at the start of emission of laser light from the first excitation laser light source. The laser apparatus according to claim 1, wherein the laser output of the first excitation laser light source is decreased from the high laser output to the reference laser output as a gradual reduction process of the laser output. 4. When starting emission of laser light from the signal laser light source, the first pulse is emitted before the laser light is emitted from the first excitation laser light source. The laser device according to any one of the above.

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