JP2006245608A - Semiconductor-laser pumped solid-state laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor-laser pumped solid-state laser apparatus capable of generating a stable, high-power and high-efficiency laser beam. <P>SOLUTION: The semiconductor-laser pumped solid-state laser apparatus is provided with a solid-state laser element 2 including an active medium, semiconductor lasers 1 for optically pumping the solid-state laser element, a power source 8 for feeding electric power to the semiconductor lasers, and an optical resonator 9, 10 for extracting the laser beam from the optically pumped solid-state laser element. In pulse-pumping the solid-state laser element by pulse-operating the semiconductor lasers 1, the current flowing through each semiconductor laser is varied within a single pulse. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor laser pumped solid-state laser device capable of generating a laser beam stably and efficiently.

  17A, 17B, and 18 are a side view and a cross-sectional view showing a configuration of a conventional semiconductor laser pumped solid-state laser device disclosed in, for example, Patent Document 1, and a waveform of an input current passed through the semiconductor laser. It is a figure which shows a laser output waveform. In FIGS. 17A and 17B, 1 is a semiconductor laser that is an excitation light source, and 2 is a slab-shaped Nd: YAG as a solid-state laser element. 3 is a semiconductor laser beam which is excitation light, and 4 is a flow tube.

  The solid laser element 2 is inserted into the flow tube 4, and cold water is allowed to flow between the solid laser element 2 and the flow tube 4 as a cooling medium 5 in order to cool the solid laser element 2. The semiconductor laser 1 is installed outside the flow tube 4, and the emitted semiconductor laser light 3 is reflected and guided by a gold mirror 6 to excite the solid-state laser element 2 through the flow tube 4. The periphery of the flow tube 4 is covered with a gold mirror 6 except for the region where the semiconductor laser light 3 is incident. Thereby, the effect of confining the semiconductor laser light 3 inside the flow tube 4 is obtained, and the excitation efficiency is improved. Reference numerals 9 and 10 are a main reflection mirror and a partial reflection mirror constituting the resonator, and 11 is a laser beam emitted to the outside of the resonator.

  Next, the operation of the solid state laser device by pulse excitation of the semiconductor laser 1 will be described. When a current is passed through the semiconductor laser 1, semiconductor laser light is emitted from the light emitting portion. Conventionally, when a semiconductor laser is pulse-operated, the current value within one pulse is always kept constant as shown in the input current waveform shown in FIG. Inside the semiconductor laser, the difference between the input energy due to the current and the output energy extracted as the semiconductor laser light is the heat generated by the semiconductor laser. Although not shown here, this amount of heat is removed by a cooling device. .

  The emitted semiconductor laser light excites the solid-state laser element 2 and spontaneous emission light is generated from the solid-state laser element 2. At this time, as shown in FIG. 17A, by providing an optical resonator constituted by mirrors 9 and 10, spontaneously emitted light is amplified while reciprocating between the resonators, and laser light having good directivity. It becomes. When reaching a certain size or larger, the laser beam 11 is emitted outside the resonator.

Advanced High-Power Lasers, SPIE Vol.3889, pp. 182-189

  By the way, it takes time for the input energy, the output energy extracted as the semiconductor laser light, and the waste heat from the cooling device to reach thermal equilibrium after the current starts to flow through the semiconductor laser 1. For this reason, when a constant current is always supplied to the semiconductor laser 1 as in the prior art, the internal temperature changes over time until the semiconductor laser 1 reaches thermal equilibrium.

  The oscillation spectrum of the semiconductor laser 1 has temperature dependence, and changes to a longer wavelength as the temperature increases. In the conventional pulse operation of the semiconductor laser 1, the oscillation spectrum within one pulse also changes with time in response to temperature changes. For this reason, the consistency between the oscillation spectrum of the semiconductor laser 1 and the absorption spectrum of the solid-state laser element 2 is reduced even in one entire pulse, causing a decrease in the absorption rate of the semiconductor laser light and the like.

  For example, when the oscillation spectrum of the semiconductor laser 1 is longer than the absorption spectrum of the solid-state laser element 2 at the time of thermal equilibrium, the absorption rate of the semiconductor laser light in the solid-state laser element 2 increases immediately after the start of excitation, but the wavelength over time due to the temperature rise. Due to the change, the absorption rate of the semiconductor laser light within one pulse decreases sequentially. As a result, there is a problem that the laser output within one pulse duration time decreases successively and the processing quality deteriorates when used for processing applications.

  Furthermore, since the pumping light absorptance immediately after the start of excitation becomes high, as shown in FIG. 18, the spike at the head of the laser pulse due to relaxation oscillation becomes prominent, which not only causes a reduction in processing quality, It has also contributed to damage to optical components such as resonator mirrors.

  The present invention has been made to solve such a problem, and in a semiconductor laser to be operated in a pulse, a change in the oscillation spectrum of the semiconductor laser within one pulse is suppressed, and a solid laser medium is efficiently excited. An object of the present invention is to obtain a semiconductor laser excitation solid-state laser device capable of generating laser light stably and with high output.

  A semiconductor laser pumped solid-state laser device according to the present invention includes: a solid-state laser element including an active medium; a semiconductor laser that optically pumps the solid-state laser element; a power source that supplies power to the semiconductor laser; and an optically pumped solid-state laser element In a semiconductor laser pumped solid-state laser device including an optical resonator for extracting laser light, when the solid-state laser element is pulse-excited by pulsing the semiconductor laser, a laser output value is obtained from the optical resonator. The value of the current flowing from the power source to the semiconductor laser is changed.

  According to the present invention, when the semiconductor laser is pulse-operated and the solid-state laser element is pulse-excited, the current value flowing from the power source to the semiconductor laser is changed within one pulse time in which the laser output value is obtained from the optical resonator. Therefore, the oscillation spectrum and output of the semiconductor laser can be controlled within one pulse, and a stable and efficient semiconductor laser pumped solid-state laser device can be obtained.

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining a semiconductor laser pumped solid-state laser device according to Embodiment 1 of the present invention.
In FIG. 1, the same reference numerals as those of the conventional example shown in FIG. In the first embodiment, the solid-state laser element 2 including the active medium is made of, for example, Nd: YAG (Nd: Yttrium Aluminum Garnet) and has a rod-like shape with a circular cross section. The solid laser element 2 is provided with a flow tube 4 so as to surround it, and a cooling medium 5 is passed between the flow tube 4 and the solid laser element 2. The semiconductor laser 1 is installed outside the flow tube 4, and the flow tube 4 is made of a medium that transmits the semiconductor laser light 3 emitted from the semiconductor laser 1, such as glass or quartz.

The semiconductor laser 1 is connected to a temperature control device 7, and the temperature control device 7 is configured so that the spectrum of the semiconductor laser light 3 emitted from the semiconductor laser 1 substantially matches the absorption spectrum of the solid-state laser element 2. The temperature is controlled.
The semiconductor laser 1 is connected to a power source 8 and supplied with current. When a current is supplied to the semiconductor laser 1 by the power supply 8, the semiconductor laser light 3 is emitted from the semiconductor laser 1 and absorbed by the solid-state laser element 2 to excite the active medium in the solid-state laser element 2.

  The total reflection mirror 9 and the partial reflection mirror 10 are provided on the optical axis with the solid-state laser element 2 interposed therebetween. The total reflection mirror 9 has a high reflectivity that almost totally reflects the laser beam 11, and the partial reflection mirror 10 has a reflectivity that reflects a part of the laser beam 11. An optical resonator for extracting the laser beam 11 from the solid state laser element 2 is configured.

Next, the operation of the semiconductor laser pumped solid-state laser device according to the first embodiment will be described in detail using a conventional technique as a comparative example.
FIG. 2 shows a current waveform supplied from the power supply 8 to the semiconductor laser 1 according to the first embodiment and the comparative example.
The value of the current passed through the semiconductor laser 1 through one pulse is constant in the comparative example (see FIG. 2A), but in the first embodiment, it is the highest in the initial stage of the pulse and decreases sequentially with the pulse duration. (See FIG. 2B). That is, the power supply 8 includes pulse current waveform control means for controlling the current waveform within one pulse.

As described above, the oscillation spectrum of the semiconductor laser 1 depends on the temperature.
FIG. 3 shows an example of the relationship between the oscillation spectrum of the semiconductor laser 1 and the temperature. As shown in FIG. 3, the oscillation spectrum of the semiconductor laser 1 becomes longer as the temperature is higher.

  When a current is passed through the semiconductor laser 1, the semiconductor laser 1 generates heat and the internal temperature starts to rise. When the heat generation amount of the semiconductor laser 1 and the waste heat amount of the temperature control device 7 reach thermal equilibrium, the temperature of the semiconductor laser 1 becomes constant. However, the temperature control device 7 has a response time, and it takes time until the inside of the semiconductor laser 1 reaches thermal equilibrium and the oscillation spectrum is fixed. Therefore, within the duration of one pulse, the oscillation spectrum changes from time to time until thermal equilibrium is reached within the semiconductor laser 1.

FIG. 4 shows the temperature change of the semiconductor laser according to the first embodiment and the comparative example.
Since the current suddenly rises simultaneously with the start of the pulse, the amount of heat generated in the semiconductor laser 1 exceeds the amount of waste heat, and heat is stored in the semiconductor laser 1 to increase the temperature. This temperature rise continues until the inside of the semiconductor laser 1 reaches thermal equilibrium, but in the comparative example, since the same energy is always input, it takes a long time to reach thermal equilibrium (FIG. 4A). reference).
On the other hand, in the first embodiment, since the input energy decreases with time from the start of the pulse, the temperature rise due to overheating can be suppressed, and the time to reach thermal equilibrium can be shortened (FIG. 4B). )reference).

  The oscillation spectrum of the semiconductor laser 1 changes corresponding to this temperature change, and if the thermal equilibrium is not reached within the time of one pulse operation, the oscillation spectrum of the semiconductor laser 1 always changes during one pulse. The change of the oscillation spectrum of the semiconductor laser 1 with respect to the pulse operation shown in FIG. In the first embodiment, it is shown as in FIG. Here, an example is shown in which the oscillation spectrum of the semiconductor laser 1 substantially matches the absorption spectrum of the solid-state laser element 2 during thermal equilibrium.

  In the case of Nd: YAG as the solid-state laser element 2, when the absorption spectrum thereof is shown in FIG. 6, the spectral absorptance has a peak at around 808 nm and rapidly decreases at wavelengths around that. In the comparative example, the change in the oscillation spectrum within one pulse of the semiconductor laser light, which is the excitation light, is large, and the absorption spectrum of the solid-state laser element 2 and the oscillation spectrum of the semiconductor laser 1 over the entire pulse cannot be matched. It is shown.

FIG. 7 shows the excitation efficiency according to the comparative example and the first embodiment.
Due to the change in the oscillation spectrum, in the comparative example, the excitation efficiency is greatly reduced at the beginning of the pulse (see FIG. 7A). On the other hand, in the first embodiment, the excitation efficiency is high throughout the pulse and can maintain a substantially constant excitation efficiency (see FIG. 7B).

  The laser output waveform finally obtained is shown in FIG. 8A in the comparative example and FIG. 8B in the first embodiment. In contrast to the large collapse of the output waveform due to the comparative example, in the first embodiment, a constant high output is obtained throughout the entire pulse. This mainly reflects the pumping efficiency. Furthermore, in the first embodiment, since a large current flows at the initial stage of the pulse, the output of the semiconductor laser 1 is high, and the decrease in pumping efficiency is compensated for. The effect of further stabilizing the output is also raised. In addition, since the current is sequentially reduced, there is an effect of reducing power consumption.

  When these lasers are used for processing, in the comparative example, the processing performance is deteriorated and the laser output per pulse is low, so that the processing efficiency is also reduced. On the other hand, in the first embodiment, the laser output waveform is also maintained in a substantially rectangular shape, and a high output is obtained for the entire pulse, so that processing with good performance and efficiency can be performed.

  Further, even when using the semiconductor laser 1 whose oscillation spectrum at the time of thermal equilibrium is shorter than the absorption spectrum of the solid-state laser element 2, in order to always realize an operation close to the state at the time of thermal equilibrium, significant excitation at the initial stage of the pulse The lower efficiency is avoided and high excitation efficiency is maintained, and the first embodiment is more effective.

  As described above, according to the first embodiment, power consumption can be reduced by controlling the current flowing from the power supply 8 to the semiconductor laser 1 to change within one pulse, that is, controlling the current to decrease sequentially. However, the solid-state laser element 2 can be excited efficiently, and a high-power laser beam can be obtained stably. In addition, since the first embodiment can be realized only by controlling the current, there is an advantage that a high-performance laser device can be obtained simply and inexpensively.

Embodiment 2. FIG.
In the first embodiment, the configuration in which the current flowing from the power source 8 to the semiconductor laser 1 over the entire pulse is sequentially reduced has been described. However, the method for reducing the current is not limited to this. For example, as shown in FIG. 9, when the current only at the initial stage of the pulse is sequentially reduced, the pumping efficiency at the initial stage of the pulse can be prevented from being lowered, and the pump can always be efficiently excited to obtain a stable laser beam.

Embodiment 3 FIG.
FIG. 10 is a diagram showing a current waveform for driving the semiconductor laser of the semiconductor laser excitation solid-state laser device according to the third embodiment of the present invention.
The third embodiment is characterized in that the current passed through the semiconductor laser 1 is sequentially increased within one pulse.
As shown in FIG. 10, by increasing the current passed through the semiconductor laser 1 within one pulse, when the oscillation spectrum of the semiconductor laser 1 is longer than the absorption spectrum of the solid-state laser element 2, the oscillation efficiency is almost constant throughout the entire pulse. Can keep.

This is explained as follows.
First, since the current value is small and the input energy is small at the initial stage of the pulse, the oscillation wavelength of the semiconductor laser 1 is shorter than that at the time of thermal equilibrium, and changes to a longer wavelength with the pulse duration. FIG. 11 (a) shows the change in excitation efficiency accompanying the change in the oscillation spectrum. In the laser output, in the region where the oscillation spectrum is long in the latter part of the pulse and the pumping efficiency is low, the semiconductor laser output becomes large due to the large current value, and this is compensated. As shown in FIG. The output is almost constant.

  Furthermore, when the oscillation spectrum of the semiconductor laser 1 is longer than the absorption spectrum in this way, in the comparative example shown in FIG. 12A, the excitation light absorption rate immediately after the start of laser oscillation becomes high. In this case, relaxation oscillation occurs immediately after the laser oscillation starts, as shown in FIG. However, according to the third embodiment, the current value can be reduced at the initial stage of the pulse to reduce the absorption rate, so that relaxation oscillation can also be suppressed. Further, by reducing the current value at the initial stage of the pulse, the power consumption is reduced, so that the laser efficiency is also improved.

  As described above, according to the third embodiment, when pulse excitation is performed using the semiconductor laser 1, the current flowing through the semiconductor laser 1 is sequentially increased, so that constant oscillation efficiency is always achieved while reducing power consumption. Not only can be maintained, but also relaxation oscillation can be effectively suppressed. As a result, even when a semiconductor laser having a long oscillation spectrum is used, the laser output of one pulse can be kept constant and high processing quality can be obtained.

Embodiment 4 FIG.
In the third embodiment, the configuration in which the current passed through the semiconductor laser 1 is sequentially increased over the entire pulse has been described. However, the method for increasing the current is not limited to this. For example, as shown in FIG. 13, if the current is increased gradually only at the initial stage of the pulse, the occurrence of relaxation oscillation is effectively suppressed regardless of the oscillation spectrum, and not only high processing quality can be obtained, It is also possible to prevent damage to the optical component.

Embodiment 5. FIG.
In the first to fourth embodiments described above, the configuration in which the current is continuously decreased or increased is shown. However, the current value may be changed stepwise. For example, as shown in FIG. 14, even if the current value is decreased stepwise only at the head portion of the pulse, the same effect as in the fourth embodiment can be obtained, and the current can be easily controlled.
In the fifth embodiment, the current flowing through the semiconductor laser 1 is changed stepwise in one step, but may be changed in a plurality of steps.

Embodiment 6 FIG.
FIG. 15 is a diagram for explaining a semiconductor laser pumped solid-state laser device according to the sixth embodiment of the present invention.
In FIG. 15, the same parts as those of the first embodiment shown in FIG. As a new code, reference numeral 12 denotes a diffuse reflection concentrator which is arranged so as to surround the solid-state laser element 2, and whose inner surface is configured to diffusely reflect the semiconductor laser light 3, and which is a semiconductor emitted from the semiconductor laser 1. An opening (not shown) for guiding the laser beam 3 to the inside is opened. Further, the optical waveguide optical element 14 for guiding the semiconductor laser light 3 made of sapphire, undoped YAG (Yttrium Aluminum Garnet), or glass having a high refractive index with respect to the semiconductor laser light 3 is formed in the opening. Is attached.

  The semiconductor laser light 3 incident on the inside of the optical waveguide optical element 14 is efficiently reflected by repeating total reflection inside the optical waveguide optical element 14 due to the refractive index difference between the optical waveguide optical element 14 and the surroundings. Waveguided. Further, the end face of the optical waveguide optical element 14 is provided with a non-reflective coating for the semiconductor laser light 3, and the semiconductor laser 1 is disposed close to the end face of the optical waveguide optical element 14. Is guided to the inside of the diffuse reflector 12 with almost no loss. In the semiconductor laser excitation solid-state laser device according to the sixth embodiment, a current is supplied to the semiconductor laser 1 as described in the first to fifth embodiments.

  Therefore, according to the sixth embodiment, after the excitation light that has not been absorbed by the solid-state laser element 2 passes through the solid-state laser element 2, it is diffusely reflected by the inner surface of the diffuse reflection collector 12, and the solid-state laser element 2 is again reflected. Since excitation is performed, the solid-state laser element 2 can be excited uniformly and efficiently, and laser light can be extracted more efficiently.

  Further, since the optical waveguide optical element 14 is attached to the diffuse reflection collector 12, the pumping light can be efficiently guided into the diffuse reflection collector 12, and a more efficient semiconductor laser excitation solid-state laser device can be obtained. Become.

  In addition, in this Embodiment 6, although the case where the diffuse reflection collector which the inner surface of a collector was comprised with a diffuse reflection surface was shown, the collector inner surface mirror-polished, for example, the inner surface of gold | metal | money What is necessary is just to have the inner surface highly reflective with respect to the semiconductor laser beam 3 like what gave the internal reflection coating with respect to the semiconductor laser beam 3 to the thing or the inner surface of glass.

  In the sixth embodiment, the optical waveguide optical element 14 has a plate shape, but may have any shape such as a wedge shape or a lens effect. Although the configuration using the optical waveguide optical element 14 is shown here, the semiconductor laser 1 may be installed close to the opening of the condenser 12 without using this. Further, if the coating is formed on the entire inner wall or a part of the opening with a coating or optical element highly reflective to the semiconductor laser light, the semiconductor laser light can be efficiently transmitted into the condenser.

Embodiment 7 FIG.
In any of the above-described embodiments, only the rod-shaped solid laser element 2 has been described. However, the cross section is not limited to a circle, and may be any shape such as a rectangle or an ellipse. In addition, it has been described that the cooling of the solid-state laser element 2 is performed by flowing the cooling medium 5 into the flow tube 4 installed so as to surround the periphery of the solid-state laser element 2, but the cooling means is not limited to this. Such cooling means may be used. For example, as shown in FIG. 16, if the solid laser element 2 having a rectangular cross section is disposed on the cooling plate 15, the solid laser element 2 can be cooled with a simple configuration.
In any of the embodiments, only the solid laser element 2 using Nd: YAG has been described. However, the present invention is not limited to this, and any solid laser element that can be optically excited by a semiconductor laser may be used. .

  As described above, according to the present invention, a solid-state laser element including an active medium, a semiconductor laser that optically excites the solid-state laser element, a power source that supplies power to the semiconductor laser, and light that extracts laser light from the optically-excited solid-state laser element In a semiconductor laser excitation solid-state laser device having a resonator, when a semiconductor laser is pulse-operated and a solid-state laser element is pulse-excited, the current flowing through the semiconductor laser is changed within one pulse. Thus, the oscillation spectrum and output of the semiconductor laser can be controlled, and a stable and efficient semiconductor laser pumped solid-state laser device can be obtained.

  In addition, since the current flowing to the semiconductor laser is sequentially decreased within one pulse, the solid-state laser element can be efficiently excited while reducing power consumption, and the change in the oscillation spectrum of the semiconductor laser is reduced. A stable and efficient semiconductor laser pumped solid-state laser device can be obtained which always maintains a constant oscillation efficiency.

  Further, by sequentially decreasing the current flowing through the semiconductor laser only at the initial stage of the pulse, it is possible to suppress a decrease in the excitation efficiency at the initial stage of the pulse and to always excite efficiently and obtain a stable laser beam.

  In addition, since the current flowing through the semiconductor laser is changed so as to increase sequentially within one pulse, not only can constant oscillation efficiency be maintained while reducing power consumption, but also it occurs immediately after the start of laser oscillation. A stable and efficient semiconductor laser-excited solid-state laser device can be obtained by suppressing possible relaxation oscillation.

  In addition, since the current flowing through the semiconductor laser is changed so as to increase sequentially only at the beginning of the pulse within one pulse, the generation of relaxation oscillation is suppressed regardless of the oscillation spectrum, and not only high or high quality can be obtained. , Damage to the optical components can be prevented.

  Further, since the current flowing through the semiconductor laser is changed so as to decrease stepwise within one pulse, in addition to the above effects, it is possible to obtain a semiconductor laser pumped solid-state laser device that is easy to control the current and is inexpensive.

  In addition, since the diffuse reflection concentrator and the optical waveguide optical element are provided, the excitation light can be efficiently guided into the diffuse reflection concentrator, and the solid laser element can be excited uniformly and efficiently. Furthermore, laser light can be extracted efficiently.

  Furthermore, by disposing the solid laser element having a rectangular cross section on the cooling plate, the solid laser element can be cooled with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the semiconductor laser excitation solid-state laser apparatus by Embodiment 1 of this invention. It is a figure which shows the electric current waveform sent through the semiconductor laser by Embodiment 1 and a comparative example. It is a figure which shows the relationship between the oscillation spectrum of a semiconductor laser, and temperature. It is a figure which shows the temperature change of the semiconductor laser by Embodiment 1 and a comparative example. It is a figure which shows the oscillation spectrum change of the semiconductor laser by Embodiment 1 and a comparative example. It is the figure which showed the absorption spectrum of the solid-state laser element. It is a figure which shows the change of the excitation efficiency of the semiconductor laser by Embodiment 1 and a comparative example. It is a figure which shows the laser output waveform in Embodiment 1 and a comparative example. FIG. 6 is a diagram showing a waveform of a current flowing through a semiconductor laser according to a second embodiment. FIG. 6 is a diagram showing a waveform of a current flowing through a semiconductor laser according to a third embodiment. It is a figure which shows the excitation efficiency and laser output waveform by Embodiment 3. It is a figure which shows the excitation efficiency and laser output waveform by the comparative example in Embodiment 3. FIG. FIG. 10 is a diagram showing a waveform of a current flowing through a semiconductor laser according to a fourth embodiment. FIG. 10 is a diagram showing a waveform of a current flowing through a semiconductor laser according to a fifth embodiment. FIG. 10 is a configuration diagram illustrating a semiconductor laser excitation solid-state laser device according to a sixth embodiment. FIG. 10 is a configuration diagram showing a semiconductor laser excitation solid-state laser device according to a seventh embodiment. It is a block diagram which shows the conventional semiconductor laser excitation solid-state laser apparatus. It is a figure which shows the electric current waveform sent through the conventional semiconductor laser.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Semiconductor laser, 2 Solid state laser element, 3 Semiconductor laser beam, 4 Flow tube, 5 Cooling medium, 6 Gold mirror, 7 Temperature control apparatus, 8 Power supply, 9 Total reflection mirror, 10 Partial reflection mirror, 11 Laser beam, 12 Diffuse reflection collector, 13 aperture, 14 optical waveguide optical element, 15 cooling plate.

Claims (2)

A solid-state laser element containing an active medium;
A semiconductor laser for optically exciting the solid-state laser element;
A power supply for supplying power to the semiconductor laser;
In a semiconductor laser pumped solid state laser device comprising: an optical resonator that extracts laser light from an optically pumped solid state laser element;
When the semiconductor laser is pulse-operated and the solid-state laser element is pulse-excited, a value of a current flowing from the power source to the semiconductor laser is changed within one pulse time in which a laser output value is obtained from the optical resonator. Semiconductor laser pumped solid state laser device. In the semiconductor laser excitation solid-state laser device according to claim 1,
The semiconductor laser pumped solid-state laser device is characterized in that the change in the current passed through the semiconductor laser is stepped.

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