JP5510298B2 - Solid state laser equipment - Google Patents

Description

  The present invention relates to a solid-state laser device, and more particularly to a solid-state laser device that can optimize the power of an RF signal applied to an acousto-optic element.

  2. Description of the Related Art Conventionally, there has been known a laser oscillation apparatus that generates a pulsed laser by controlling an RF signal applied to an acousto-optic element (see, for example, Patent Document 1).

JP 2009-218446 A ([0012])

In a solid-state laser device such as the above-described laser oscillation device, if the RF signal power is sufficiently increased and the RF signal is turned on, the loss of the resonator including the acoustooptic device increases, and the laser oscillation is not performed and is included in the resonator. The gain of the laser medium increases. When the RF signal is rapidly turned off from this state, the loss of the resonator is reduced, laser oscillation is performed, and a pulsed laser is output from the laser medium whose gain has been increased.
Insufficient RF signal power results in unstable pulsed laser output, and thus the RF signal power is generally set to several W or more.
However, there is a problem in that heat generation in the RF signal generation circuit is large and power consumption of the entire apparatus is increased.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a solid-state laser device capable of optimizing the power of an RF signal applied to an acoustooptic device so that heat generation in the RF signal generation circuit can be suppressed and power consumption of the entire device can be reduced. It is in.

In a first aspect, the present invention includes a semiconductor laser (1) that generates excitation laser light, a solid-state laser medium (2) that is excited by the excitation laser light, and the solid-state laser medium (2). An acoustooptic device (4) for controlling the loss of the resonator (3), a photodetector (6) for detecting a pulse laser, and the acoustooptic device (4). And an RF signal generation circuit (9) for generating an RF signal to the control circuit and a control circuit (8) for controlling the power of the RF signal. The control circuit (8) changes the power of the RF signal. Then, the variation of the pulse laser with respect to the power of the RF signal is measured, the power of the minimum RF signal that can be tolerated is obtained, and the power of the RF signal is set based on the power of the minimum RF signal. Solid state To provide a device.
In the solid-state laser device according to the first aspect, the power of the RF signal is changed, the dispersion of the pulse laser with respect to the power of the RF signal is measured, and the power of the minimum RF signal that can be tolerated is obtained. A minimum RF signal power is applied to the acousto-optic device. Alternatively, in order to provide a margin, the acoustooptic device is given a power of an RF signal slightly larger than the power of the minimum RF signal. As the allowable variation is increased, the power of the RF signal can be made smaller than before, so that heat generation in the RF signal generation circuit can be suppressed and the power consumption of the entire apparatus can be reduced.
It is preferable that the allowable variation can be set by the user according to the application.

  If it takes a long time to turn the RF signal from on to off, the original pulse is not generated and becomes a double pulse. On the other hand, in the present invention, since the power of the RF signal can be reduced, the time for turning off the RF signal can be shortened, and a stable pulse laser can be generated in this respect as well.

In a second aspect, the present invention provides the solid-state laser apparatus according to the first aspect, wherein the control circuit (8) calculates an energy dispersion value from the energy of each laser pulse of three pulses or more for a certain power of an RF signal. The calculation is repeatedly performed while changing the power of the RF signal, the power of the minimum RF signal that is equal to or less than an allowable dispersion value is obtained, and the power of the RF signal is calculated based on the power of the minimum RF signal. A solid-state laser device is provided.
In the solid-state laser device according to the second aspect, the dispersion of the pulse laser is measured using the energy dispersion value of each pulse as an index.

In a third aspect, the present invention is the solid-state laser device according to the first aspect, wherein the control circuit (8) measures the energy of the laser pulse for a predetermined time for a certain power of the RF signal three times or more. The calculation of the dispersion value of the average pulse power is repeated while changing the power of the RF signal, and the power of the minimum RF signal that is equal to or less than the allowable dispersion value is obtained, and the minimum RF signal A solid-state laser device characterized in that the power of the RF signal is set based on the power.
In the solid-state laser device according to the third aspect, the dispersion of the pulse laser is measured using the dispersion value of the average pulse power of the laser pulse for a predetermined time as an index.

In a fourth aspect, the present invention provides the solid-state laser apparatus according to any one of the first to third aspects, wherein the control circuit (8) intermittently optimizes the power of the RF signal. A solid-state laser device is provided.
In the solid-state laser device according to the fourth aspect, for example, by optimizing the power of the RF signal once a day, it is possible to correct a temporal change factor such as a decrease in the diffraction effect of the acoustooptic device.

In a fifth aspect, the present invention provides the solid-state laser apparatus according to any one of the first to third aspects, wherein the control circuit (8) continuously optimizes the power of the RF signal. A solid-state laser device is provided.
In the solid-state laser device according to the fifth aspect, it is possible to correct disturbance factors such as a change in environmental temperature.

  According to the solid-state laser device of the present invention, as the allowable variation is increased, the power of the RF signal can be reduced as compared with the conventional one. Therefore, heat generation in the RF signal generation circuit can be suppressed, and the power consumption of the entire device can be reduced. .

1 is a configuration explanatory diagram illustrating a solid-state laser device according to a first embodiment. FIG. 3 is a flowchart showing RF power (RF signal power) setting processing in the solid-state laser apparatus according to the first embodiment. It is a graph which shows the relationship between RF power and a dispersion value. It is a wave form diagram of a pulse laser output. FIG. 10 is a flowchart showing an RF power setting process in the solid-state laser apparatus according to the second embodiment. It is a graph which shows the relationship between RF power and a dispersion value.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

Example 1
FIG. 1 is an explanatory diagram illustrating a solid-state laser device 100 according to the first embodiment.
This solid-state laser device 100 includes a semiconductor laser 1 that generates excitation laser light, an input-side mirror 3a, a solid-state laser medium 2 that is excited by excitation laser light, an acoustooptic device 4 that constitutes a Q switch, and an output side. A mirror 3 b, a beam splitter 5 that branches a part of the pulse laser that has passed through the output side mirror 3 b, a photodetector 6 that detects the pulse laser branched by the beam splitter 5, and a pulse from the output of the photodetector 6 An energy monitor circuit 7 that measures the energy of the laser, an RF signal generation circuit 9 that generates an RF signal to the acoustooptic device 4, and indicates the magnitude of the power of the RF signal and controls on / off of the RF signal A control circuit 8 and an allowable value setting operation unit 10 for an operator to set an allowable value are provided.
The resonator 3 includes an input side mirror 3a, a solid-state laser medium 2, an acoustooptic device 4, and an output side mirror 3b.

FIG. 2 is a flowchart showing RF power setting processing in the control circuit 8. This RF power setting process is executed intermittently, for example, when the power is turned on or when a certain time has elapsed.
In step S1, the allowable value set by the allowable value setting operation unit 10 is read.
In step S2, as shown in FIG. 3, the RF power is set to an initial value that ensures that the read allowable value is not satisfied. A table of initial values for various allowable values may be stored in advance, and an initial value corresponding to the read allowable value may be searched to obtain an initial value that ensures that the read allowable value is not satisfied. .

  In step S3, the energy of each pulse of the laser output as shown in FIG. 4 is measured, and the energy dispersion value E is calculated from the measurement results of three or more pulses. Alternatively, measuring the average pulse power including a plurality of pulses is repeated three or more times, and the dispersion value E of the average pulse power is calculated from the measurement result.

  In step S4, if the calculated dispersion value E satisfies the allowable value, the process ends. If not, the process proceeds to step S5. If the RF power is the initial value, the dispersion value E does not necessarily satisfy the allowable value, so the process proceeds to step S5.

  In step S5, the RF power is increased by a predetermined unit amount (for example, 0.1 W) determined in advance. Then, the process returns to step S3.

  By repeating steps S3 to S5, as shown in FIG. 3, the set value of the RF power becomes the minimum value that satisfies the allowable value.

  According to the solid-state laser device 100 of the first embodiment, since the power of the RF signal is the minimum value that satisfies the allowable value, heat generation in the RF signal generation circuit 9 can be suppressed, and the power consumption of the entire device can be reduced. Further, the time for turning off the RF signal can be shortened, and a stable pulse laser can be generated also in this respect.

-Example 2-
FIG. 5 is a flowchart illustrating the RF power setting process in the control circuit 8 according to the second embodiment. This RF power setting process is always executed continuously.
In step S11, as shown in FIG. 6, the RF power is set to the maximum value.

  In step S12, the RF power is increased by a predetermined margin (for example, 0.5 W). When the RF power is the maximum value, the maximum value remains.

  In step S13, the energy of each pulse of the laser output as shown in FIG. 4 is measured, and the energy dispersion value E is calculated from the measurement results of three or more pulses. Alternatively, measuring the average pulse power including a plurality of pulses is repeated three or more times, and the dispersion value E of the average pulse power is calculated from the measurement result.

  In step S14, the allowable value set by the allowable value setting operation unit 10 is read.

  In step S15, if the calculated dispersion value E satisfies the allowable value, the process proceeds to step S16, and if not, the process returns to step S12.

  In step S16, the RF power is decreased by a predetermined unit amount (for example, 0.1 W). Then, the process returns to step S13.

  By repeating steps S12 to S16, as shown in FIG. 6, the RF power set value is a lower value that is smaller by the unit amount than the minimum value that satisfies the allowable value, and an upper value that is larger by the margin amount. Will cycle between them.

  According to the solid-state laser device 100 of the second embodiment, the power of the RF signal becomes a value that is suppressed so as to satisfy the allowable value, so that heat generation in the RF signal generation circuit 9 can be suppressed, and the power consumption of the entire device is also small. I can do it. Further, the time for turning off the RF signal can be shortened, and a stable pulse laser can be generated also in this respect.

  The solid-state laser device of the present invention can be used in the bioengineering field and the measurement field.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Solid-state laser medium 3 Resonator 3a Input side mirror 3b Output side mirror 4 Acoustooptic device 5 Beam splitter 6 Photodetector 7 Energy monitor circuit 8 Control circuit 9 RF signal generation circuit 10 Allowable value setting operation part 100 Solid state laser apparatus

Claims (5)

Installed in a semiconductor laser (1) that generates excitation laser light, a solid-state laser medium (2) that is excited by the excitation laser light, and a resonator (3) that includes the solid-state laser medium (2). And an acoustooptic device (4) for controlling the loss of the resonator (3), a photodetector (6) for detecting a pulse laser, and an RF signal generator for generating an RF signal to the acoustooptic device (4). A circuit (9) and a control circuit (8) for maintaining the power of the RF signal at a set predetermined value, the predetermined value changing the power of the RF signal to A solid-state laser device characterized in that a variation of the pulse laser with respect to power is measured, and the value is set based on the power of a minimum RF signal that is acceptable variation. 2. The solid-state laser device according to claim 1, wherein the control circuit (8) calculates the energy dispersion value from the energy of each laser pulse of three pulses or more for a certain power of the RF signal. The solid-state laser is characterized in that the power of the minimum RF signal that is equal to or less than an allowable dispersion value is obtained repeatedly while changing the power and the power of the RF signal is set based on the power of the minimum RF signal apparatus. 2. The solid-state laser device according to claim 1, wherein the control circuit (8) measures the average pulse power of a laser pulse for a predetermined time for a certain power of an RF signal three times or more to obtain a dispersion value of the average pulse power. Is repeatedly performed while changing the power of the RF signal, and the power of the minimum RF signal that is equal to or less than an allowable dispersion value is obtained, and the RF signal power is calculated based on the power of the minimum RF signal. A solid-state laser device characterized by setting power. The solid-state laser apparatus according to any one of claims 1 to 3, wherein the control circuit (8) intermittently optimizes the power of the RF signal. The solid-state laser apparatus according to any one of claims 1 to 3, wherein the control circuit (8) continuously optimizes the power of the RF signal.

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