JP2021034464A - Laser device and laser stabilization method - Google Patents

Abstract

To provide a laser device and a laser stabilization method that can restart a search process without requiring a waiting time when the search process of a target saturated absorption line fails.SOLUTION: A control unit 53 of a laser device includes an actuator control unit 531 that sweeps a drive voltage V, a search unit 532 that executes search processing of detecting a singular point on the basis of a second derivative signal SL2, and storing a voltage value of a drive voltage V at the time when the singular point is detected in a memory 54, and a noise determination unit 533 that determines noise from a plurality of singular points detected in the search processing. When the noise detected as the singular point is present, the search unit 532 performs the search processing while the drive voltage V changes in the decreasing direction from a value smaller than the voltage value at the time when the noise is detected.SELECTED DRAWING: Figure 2

Description

The present invention relates to a laser apparatus and a laser stabilization method.

Conventionally, a laser device that stabilizes the oscillation frequency of laser light to a specific saturated absorption line of an absorption cell has been known.
For example, the laser device described in Patent Document 1 detects a resonator that emits laser light, an absorption cell that is irradiated with laser light emitted from the resonator, and a laser beam that has passed through the absorption cell, and detects a light detection signal. It is equipped with an optical detector that outputs. In this laser device, the saturation absorption line is searched based on the light detection signal and the second-order differential signal of the light detection signal while changing the resonator length within a predetermined range, and the target saturation absorption line is observed. By realizing the instrument length, the oscillation frequency of the laser beam is fixed to the target saturation absorption line.

Japanese Unexamined Patent Publication No. 2013-016713

By the way, in the laser apparatus described in Patent Document 1 described above, noise is erroneously detected as a saturated absorption line when the laser beam is in a state of multi-mode oscillation instead of single-mode oscillation or when it is affected by disturbance. It may end up. If noise is erroneously detected as a saturated absorption line, the count number of the saturated absorption line becomes a value different from the parameter stored in the memory, and the search process becomes an error. In order to restart the search process without any problem, it is necessary to wait until the noise settles down, which increases the time required for the entire search process.

An object of the present invention is to provide a laser apparatus and a laser stabilization method capable of restarting the search process without requiring a waiting time when the search process of the target saturated absorption line results in an error.

The laser apparatus of the present invention detects a resonator that outputs a laser beam, an absorption cell into which the laser beam output from the resonator is incident, and the laser beam that has passed through the absorption cell, and detects a light detection signal. The light detection unit that outputs the light detection signal, the differential calculation unit that generates the second-order differential signal of the light detection signal, the actuator that changes the resonator length of the resonator according to the applied drive voltage, and the drive voltage. A laser device including an output actuator drive unit and a control unit, wherein the control unit is an actuator control unit that sweeps the drive voltage in an increasing direction or a decreasing direction, and while the driving voltage is swept. A search unit that detects a singular point based on the second-order differential signal and stores the voltage value of the driving voltage at the time when the singular point is detected in a memory, and a plurality of detection units detected in the search process. When the noise detected as the singular point is present, the search unit drives the noise from a value larger than the detected voltage value. The search process is performed while the voltage is swept in the increasing direction or while the driving voltage is swept in the decreasing direction from a value smaller than the detected voltage value.

According to the present invention, when noise is detected as a singular point in the immediately preceding search process and an error occurs in the search process for the target saturated absorption line, the next time from the position beyond the voltage range where the noise is detected, the noise is detected. Search processing is performed. Therefore, the search process can be restarted without requiring a waiting time until the noise settles down.

In the laser apparatus of the present invention, when the noise detected as the singularity is present, the actuator control unit sweeps the driving voltage from a value larger than the voltage value at which the noise is detected in a decreasing direction. Or, it is preferable to sweep the noise from a value smaller than the detected voltage value in the decreasing direction.
According to the present invention as described above, the sweep time of the drive voltage can be shortened as compared with the case where the drive voltage is decreased from the maximum voltage value or the drive voltage is increased from the minimum voltage value.

The laser stabilization method of the present invention detects a resonator that outputs a laser beam, an absorption cell into which the laser beam output from the resonator is incident, and the laser beam that has passed through the absorption cell, and emits light. An optical detection unit that outputs a detection signal, a differential calculation unit that generates a second-order differential signal of the optical detection signal, an actuator that changes the resonator length of the resonator according to an applied drive voltage, and the drive. Using a laser device including an actuator drive unit that outputs a voltage, a singular point is detected based on the quadratic differential signal while the drive voltage is changed in an increasing direction or a decreasing direction, and the singular point is detected. A search step of performing a search process for storing the voltage value of the drive voltage at the time when the signal is generated, a noise discrimination step of discriminating noise from a plurality of the singular points detected in the search step, and detection as the singular point When the noise is present, the drive voltage is changed from a value larger than the voltage value at the time when the noise is detected to an increasing direction, or the drive voltage is changed at the time when the noise is detected. It is characterized in that a re-search step of carrying out the search process is performed while the voltage value is changed from a value smaller than the voltage value in a decreasing direction.
According to the laser stabilization method of the present invention, the same effect as that of the laser apparatus of the present invention described above can be obtained.

The figure which shows typically the laser apparatus which concerns on one Embodiment of this invention. The block diagram which shows the control apparatus in the laser apparatus of the said embodiment. The graph which shows the change of each output value of the light detection signal and the 2nd derivative signal when the drive voltage is changed. The graph which shows by enlarging a part about the change of each output value of the light detection signal and the 2nd derivative signal shown in FIG. The flowchart for demonstrating the laser stabilization method of the said Embodiment. The figure which shows the example which noise is generated in the light detection signal and the 2nd derivative signal shown in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Laser device]
As shown in FIG. 1, the laser device 1 includes an excitation light source 10, a resonator 20, a waveguide optical unit 30, a detection unit 40, and a control device 50.
The excitation light source 10 is driven by the control of the control device 50, and when the drive current flows, for example, the excitation light La1 in the vicinity of 808 nm is emitted.

The resonator 20 includes a laser medium 21, a nonlinear optical crystal 22, an etalon 23, a resonator mirror 24, an actuator 25, and a housing 26 for accommodating them.
The laser medium 21 is, for example, Nd: constituted by YVO ₄ crystal, etc., are excited by the excitation light La1, it emits a wavelength in the vicinity of 1064nm of light (fundamental light). Further, the surface of the laser medium 21 on which the excitation light La1 is incident is coated with a coating that transmits the excitation light La1 and reflects the fundamental wave light.

The nonlinear optical crystal 22 is composed of, for example, a KTP crystal, and converts the fundamental wave light emitted from the laser medium 21 into light having a wavelength of, for example, around 532 nm (second harmonic light).
The etalon 23 sets the fundamental wave light and the second harmonic light to a single mode by transmitting light having a predetermined wavelength.

The resonator mirror 24 is attached to the housing 26 via the actuator 25. The surface of the resonator mirror 24 on the etalon 23 side is coated with a coating that reflects the fundamental wave light and transmits the second harmonic light.
The actuator 25 is composed of, for example, a piezo element or the like, and is driven by the control of the control device 50 to change the position of the resonator mirror 24. That is, the actuator 25 changes the cavity length.

In such a resonator 20, the fundamental wave light emitted from the laser medium 21 reciprocates between the laser medium 21 and the resonator mirror 24, and is converted into the second harmonic light by the nonlinear optical crystal 22. The second harmonic light converted into the nonlinear optical crystal 22 passes through the resonator mirror 24 and is emitted from the resonator 20 as laser light La2.

The waveguide optical unit 30 is composed of, for example, a plurality of optical members including a λ / 2 plate 31 and a first polarization beam splitter 32. In the waveguide optical unit 30, the laser beam La2 is incident on the first polarization beam splitter 32 with the polarization direction adjusted by the λ / 2 plate 31. The light incident on the first polarized beam splitter 32 is separated into P-polarized transmitted light and S-polarized reflected light, of which the S-polarized reflected light (laser light La3) is emitted to the outside of the laser apparatus 1. And used for length measurement, etc. The P-polarized laser beam La4 that has passed through the first polarization beam splitter 32 is incident on the detection unit 40.

The detection unit 40 includes a light incident unit 42 on which the laser light La4 of the waveguide optical unit 30 is incident, a light absorption unit 43 through which the laser light La4 from the light incident unit 42 is transmitted, and a laser light transmitted through the light absorption unit 43. The light reflecting unit 44 is provided so as to reflect the light and re-enter the light absorbing unit 43.

The light incident portion 42 is a portion where the P-polarized laser beam La4 transmitted through the first polarization beam splitter 32 of the waveguide optical unit 30 is incident. The light incident portion 42 is provided with a second polarization beam splitter 421, a λ / 4 plate 422, and a light detection unit 424.
The second polarization beam splitter 421 transmits the P-polarized laser light La4 incident on the light incident unit 42, and reflects the S-polarized laser light incident on the absorption cell 431 to the light detection unit 424.
The λ / 4 plate 422 converts the P-polarized laser beam La4 incident from the second polarization beam splitter 421 side into circular polarization and emits it to the absorption cell 431 side. Further, the circularly polarized laser light incident from the absorption cell 431 side is converted into S polarized light and emitted to the second polarization beam splitter 421 side.
The photodetector 424 detects the light reflected by the second polarization beam splitter 421 and outputs the photodetection signal SL1 according to the light intensity to the control device 50.

The light absorption unit 43 includes an absorption cell 431. An enclosed gas (for example, iodine) is enclosed in the absorption cell 431, and among the incident laser light, light having a predetermined wavelength corresponding to the absorption characteristics of the enclosed gas is absorbed.
The light reflecting portion 44 is provided on the side opposite to the light incident portion 42 via the light absorbing portion 43. The light reflecting unit 44 includes a reflecting mirror 442 that reflects the laser light transmitted through the absorption cell 431.

In the present embodiment, the P-polarized laser beam La4 incident on the light incident unit 42 passes through the second polarization beam splitter 421 and the λ / 4 plate 422 and is emitted toward the absorption cell 431 of the light absorption unit 43. .. The laser light transmitted through the absorption cell 431 is reflected by the reflection mirror 442 of the light reflection unit 44 and is again incident on the absorption cell 431. Then, the transmitted laser light that has not been absorbed by the enclosed gas inside the absorption cell 431 passes through the λ / 4 plate 422 again and is incident on the second polarization beam splitter 421. Therefore, the laser light re-entering the second polarization beam splitter 421 becomes S-polarized light by passing through the λ / 4 plate 422 twice, is reflected by the second polarization beam splitter 421, and is reflected by the light detection unit 424. Being incident.

Although the description is omitted in the present embodiment, the nonlinear optical crystal 22 and the etalon 23 may each be provided with an angle adjusting mechanism controlled by the control device 50. Further, the nonlinear optical crystal 22, the etalon 23, the housing 26, and the light absorbing unit 43 may each be provided with a temperature control mechanism controlled by the control device 50.

The control device 50 controls the operation of the actuator 25 based on the photodetection signal SL1 input from the photodetector 424, and stabilizes the oscillation frequency of the laser beam La2 to a specific saturation absorption line.
Specifically, as shown in FIG. 2, the control device 50 includes an actuator drive unit 51 that applies a drive voltage V to the actuator 25, and a second-order differential signal SL2 and a third-order differential signal based on the light detection signal SL1. It includes a differential calculation unit 52 that generates SL3, a control unit 53 that outputs a control signal Sc to an actuator drive unit 51 based on the signals SL1 to SL3, and a memory 54.

The control unit 53 functions as an actuator control unit 531, a search unit 532, and a noise discrimination unit 533 by reading and executing the program stored in the memory 54.
The actuator control unit 531 controls the drive voltage V applied to the actuator 25 from the actuator drive unit 51 by outputting a control signal Sc to the actuator drive unit 51. Thereby, the resonator length of the resonator 20 is controlled.
The search unit 532 detects a feature point that appears in the second derivative signal SL2 and is considered to be a saturated absorption line, and performs a search process for searching for a target saturated absorption line from the detected feature point.
The noise discrimination unit 533 determines whether or not each feature point detected by the search unit 532 is noise.

[Saturated absorption line]
FIG. 3 is a diagram showing a photodetection signal SL1 and a second derivative signal SL2. In FIG. 3, the output values of the signals SL1 and SL2 are on the vertical axis, the drive voltage V to the actuator 25 is on the horizontal axis, and the drive voltage V is changed (when the resonator length is changed). It is a figure which shows the change of signals SL1 and SL2.
Since the photodetection signal SL1 inverts and amplifies the signal photoelectrically converted by the photodetector 424, the voltage polarity is inverted. That is, when the absorption rate of the laser light with respect to the absorption cell 431 is high, the output value of the photodetection signal SL1 increases.

As shown in FIG. 3, when the drive voltage V is changed within a predetermined range, the range in which the output value of the photodetection signal SL1 increases, that is, the range in which the laser beam is absorbed by the absorption cell 431 (hereinafter, absorption regions Rv1 to 1). Rv4) is observed at a predetermined cycle. In the second derivative signal SL2, peak groups M1 to M4, which are a group of saturated absorption lines, appear in each absorption region Rv1 to Rv4.
In the present embodiment, one or more saturated absorption lines form a saturated absorption line group. For example, the peak group M2 shown in FIG. 4 includes a saturated absorption line group N1 (saturated absorption line a1), a saturated absorption line group N2 (saturated absorption line a2 to a5), and a saturated absorption line group N3 (saturated absorption line a6 to a9). ), Saturated absorption line group N4 (saturation absorption line a10), saturation absorption line group N5 (saturation absorption line a11 to a14), and saturation absorption line group N6 (saturation absorption line a15) are observed.
The number and combination of saturated absorption lines belonging to each of the above peak groups M1 to M4 and the number of saturated absorption lines belonging to each saturated absorption line group are stored in the memory 54 as parameters.

[Laser stabilization method]
The laser stabilization method in the laser apparatus 1 will be described with reference to the flowchart shown in FIG. In the following, for convenience of explanation, the target saturated absorption line is referred to as the saturated absorption line a10 belonging to the peak group M2.

(Search process)
First, the actuator control unit 531 sets the drive voltage V applied to the actuator 25 to the maximum voltage value (step S1).

After step S1, the actuator control unit 531 gradually sweeps the drive voltage V from the maximum voltage value to the minimum voltage value. While the drive voltage V is swept, the search unit 532 searches for the peak group M2 to which the target saturation absorption line a10 belongs (step S2; search step).

In step S2, the search unit 532 detects a singular point when, for example, the output value of the secondary differential signal SL2 is equal to or higher than a predetermined threshold value Vth1, and the voltage value of the drive voltage V at the time when the singular point is detected. (See, for example, FIG. 4).

After step S2, the control unit 53 determines whether or not the peak group M2 can be searched (step S3). Specifically, the control unit 53 refers to various parameters related to the peak group M2 from the memory 54, and determines whether or not a group of singular points matching the various parameters has been detected.

If No is determined in step S3, the process proceeds to step S12. The processing after step S12 will be described later.

On the other hand, when it is determined Yes in step S3, the actuator control unit 531 sets the drive voltage V to a value slightly before the absorption region Rv2 corresponding to the peak group M2 in the sweep direction of the next drive voltage V. Set (step S4).

Next, the actuator control unit 531 sweeps the drive voltage V from the value before the absorption region Rv2 to the value behind the absorption region Rv2, for example, in the increasing direction. While the drive voltage V is swept, the search unit 532 searches for the peak group M2 to which the target saturation absorption line a10 belongs (step S5). The method for searching for the peak group M2 is the same as in step S2 described above.
After step S5, the control unit 53 determines whether or not the target peak group M2 can be searched, as in step S3 (step S6).

If No is determined in step S6, the process proceeds to step S15 to perform error processing. The error handling outputs, for example, information notifying the user of the error.

On the other hand, when it is determined Yes in step S6, the actuator control unit 531 sweeps the drive voltage V from the value before the absorption region Rv2 toward the value behind the absorption region Rv2, for example, in the decreasing direction. .. While the drive voltage V is swept, the search unit 532 searches for the target saturation absorption line a10 (step S7).
In step S7, the search unit 532 counts the number of detections of the singular point while detecting the singular point by the same method as in step S2 described above. Then, when the sweep direction of the drive voltage V is in the decreasing direction, the singular point detected the fifth time is detected as the target saturation absorption line a10, and the voltage value Vg at the time of detection is stored in the memory 54.

Next, the control unit 53 determines whether or not the target saturation absorption line a10 can be searched (step S8). In step S8, for example, when the voltage value Vg at the time when the singular point to be the saturation absorption line a10 is detected is within a predetermined ideal range, it is determined that the target saturation absorption line a10 can be searched. be able to.

If No is determined in step S8, the process proceeds to step S15 and error processing is performed.
On the other hand, when it is determined Yes in step S8, the actuator control unit 531 fixes the drive voltage V to the voltage value Vg at which the target saturation absorption line a10 is detected (step S9). As a result, the oscillation frequency of the laser beam La2 is adjusted to the target saturation absorption line a10.

After step S9, the control unit 53 monitors whether or not the output value of the second derivative signal SL2 is stable above, for example, the threshold value Vth1 (step S10). As a result, it is monitored whether or not the oscillation frequency of the laser beam La2 is stabilized at the target saturation absorption line a10. If it is determined that the output value of the second derivative signal SL2 is smaller than the threshold value Vth1 (step S10: No), the return process of step S11 is performed. Since the restoration process is the same as that of the conventional technique, the description thereof will be omitted in the present embodiment.

(Research process)
When No is determined in step S3 described above, the noise discrimination unit 533 discriminates noise from a plurality of singular points detected in step S2 (step S12; noise discrimination step).

The specific method of the noise discrimination unit 533 is not particularly limited, but noise can be discriminated by using the output value of the photodetection signal SL1 and the parameters stored in the memory 54.
For example, when the laser light is in a state of multi-mode oscillation instead of single-mode oscillation or is affected by disturbance, noise is likely to occur in the range of the drive voltage V at which the laser light starts to be absorbed by the absorption cell 431. This noise may be detected as a singular point when each output value of the second derivative signal SL2 becomes the threshold value Vth1 or more. For example, FIG. 6 illustrates noise generated near the positive boundary of the absorption region Rv2. In the present embodiment, based on the nature of such noise, the singularity detected near each boundary of the absorption regions Rv1 to Rv4 may be discriminated as noise.
Further, the saturated absorption line is observed while the laser beam is absorbed by the absorption cell 431. Therefore, the noise discrimination unit 533 may discriminate the singular point detected when the light detection signal SL1 is the threshold value Vth2 or less as noise.
Further, the noise discrimination unit 533 may select a singular point that matches the parameter stored in the memory 54 from the plurality of detected singular points, and discriminate the remaining unselected singular points as noise.

Next, the actuator control unit 531 determines whether or not the noise determined in step S12 is present (step S13).
When noise is present (Yes in step S13), the actuator control unit 531 increases the drive voltage V, which was the minimum voltage value at the end of step S2, and is slightly smaller than the voltage value at which noise is detected. The drive voltage V is set to a small value (return value). That is, the drive voltage V is set to the value at the position where noise has passed in the voltage sweep direction (decrease direction) of step S2 (step S14).

In step S14, when a plurality of noises are present, a value slightly smaller than the voltage value is set as the recovery value Vr with reference to the largest voltage value among the voltage values at which the noise is detected.
Further, the "value slightly smaller than the voltage value at which noise is detected" may be a value that is a predetermined amount smaller than the voltage value at which noise is detected so that the influence of noise can be avoided.
For example, FIG. 6 illustrates a return value Vr that is set when noise is present near the positive boundary of the absorption region Rv2.

Then, the process returns to step S2. In step S2, the actuator control unit 531 gradually reduces the drive voltage V from the return value to the minimum voltage value, and the search unit 532 searches for the peak group M2 to which the target saturation absorption line a10 belongs (research). Process).

On the other hand, when there is no noise (No in step S13), the process returns to step S1 with a waiting time in between, and the flow is restarted.

[Effect of this embodiment]
In the laser device 1 of the present embodiment, the control unit 53 detects a singular point based on the actuator control unit 531 that sweeps the drive voltage V and the secondary differential signal SL2 while the drive voltage V is swept. A search unit 532 that performs a search process for storing the voltage value of the drive voltage V at the time when a singular point is detected in the memory 54, and a noise discrimination unit 533 that discriminates noise from a plurality of singular points detected in the search process. Has. Then, when the noise detected as a singular point is present, the search unit 532 performs the search process while the drive voltage V changes in the decreasing direction from a value smaller than the voltage value at the time when the noise is detected.

In such an embodiment, when noise is detected as a singular point in the immediately preceding search process and an error occurs in the search process for the target saturated absorption line, the noise is detected from a position beyond the voltage range. The next search process is performed. Therefore, the search process can be restarted without requiring a waiting time until the noise settles down.
Further, in the present embodiment, since noise is avoided in the re-search process, it is possible to suppress unnecessary consumption of the capacity of the memory 54.

In the laser device 1 of the present embodiment, when the noise detected as a singular point is present, the actuator control unit 531 sweeps the drive voltage V from a value smaller than the voltage value at which the noise is detected in the decreasing direction.
According to such an embodiment, the sweep time of the drive voltage V can be shortened as compared with the case where the drive voltage V is reduced from the maximum voltage value.

[Modification example]
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.

For example, in the above embodiment, when the noise detected as a singular point is present, the actuator control unit 531 may sweep the drive voltage V from a value larger than the voltage value at which the noise is detected in the increasing direction. Similarly, when the noise detected as a singular point is present, the search unit 532 performs the search process while the drive voltage V changes in the increasing direction from a value larger than the voltage value at the time when the noise is detected. May be good.
Even with such a modified example, the same effect as that of the above-described embodiment can be obtained.

In the above embodiment, when the noise detected as a singular point is present (Yes in step S13), the search unit 532 uses the voltage value at which the noise is detected instead of the process of setting the return value in step S14. The area including is set as the recording prohibited area. Further, after the recording prohibition region is set, the process returns to step S1, and the actuator control unit 531 may set the drive voltage V to the maximum voltage value.
According to such a modification, as in the above embodiment, the process of storing the singularity is performed from the position beyond the voltage range where the noise is detected, so that the waiting time until the noise settles is not required. The search process can be restarted. Further, according to such a modification, the resonator length can be stably controlled by sweeping the drive voltage V from the maximum voltage value.

If No in step S6 of the embodiment, instead of performing error processing in step S15, the same processing as in steps S12 to S14 may be performed. In this modification, if noise detected as a singular point is present, the drive voltage V is set to the value at the position where the noise has passed, and then the process returns to step S5. Then, the search process can be performed from the position where the noise is detected after the voltage value is detected.
Similarly, if No in step S8 of the embodiment, instead of performing error processing in step S15, the same processing as in steps S12 to S14 may be performed. In this modification, when the noise detected as a singular point is present, the drive voltage V is set to the value at the position where the noise has passed, and then the process returns to step S7. Then, the search process can be performed from a position beyond the voltage range in which noise is detected.

1 ... laser device, 10 ... excitation light source, 20 ... resonator, 21 ... laser medium, 22 ... non-linear optical crystal, 23 ... etalon, 24 ... resonator mirror, 25 ... actuator, 26 ... housing, 30 ... waveguide light Faculty, 32 ... 1st polarized beam splitter, 40 ... detector, 42 ... light incident, 421 ... 2nd polarized beam splitter, 424 ... light detector, 43 ... light absorber, 431 ... absorption cell, 44 ... light reflection Unit, 442 ... Reflection mirror, 50 ... Control device, 51 ... Actuator drive unit, 52 ... Differential calculation unit, 53 ... Control unit, 513 ... Actuator control unit, 532 ... Search unit, 533 ... Noise discrimination unit, 54 ... Memory, La1 ... excitation light, La2 to La4 ... laser light, M1 to M4 ... peak group, Rv1 to Rv4 ... absorption region, SL1 ... light detection signal, SL2 ... second-order differential signal, V ... drive voltage, Vg ... voltage value, Vth1 , Vth2 ... Threshold.

Claims (3)

A resonator that outputs laser light and
An absorption cell into which the laser beam output from the resonator is incident and
A photodetector that detects the laser beam that has passed through the absorption cell and outputs a light detection signal.
A differential calculation unit that generates a second derivative signal of the photodetection signal,
An actuator that changes the resonator length of the resonator according to the applied drive voltage, and
The actuator drive unit that outputs the drive voltage and
A laser device including a control unit
The control unit
An actuator control unit that sweeps the drive voltage in the increasing or decreasing direction,
A search unit that detects a singular point based on the second derivative signal while the drive voltage is swept, and performs a search process for storing the voltage value of the drive voltage at the time when the singular point is detected in a memory. ,
A noise discriminating unit that discriminates noise from a plurality of the singular points detected in the search process is provided.
When the noise detected as the singularity is present, the search unit is in the search unit while the driving voltage is swept in an increasing direction from a value larger than the voltage value at the time when the noise is detected, or when the noise is generated. A laser apparatus characterized in that the search process is performed while the drive voltage is swept in a decreasing direction from a value smaller than the voltage value at the time of detection. In the laser apparatus according to claim 1,
When the noise detected as the singularity is present, the actuator control unit sweeps the driving voltage from a value larger than the voltage value at the time when the noise is detected in a decreasing direction, or the noise. A laser device characterized in that a value smaller than the voltage value at the time when is detected is swept in a decreasing direction. A resonator that outputs laser light and
An absorption cell into which the laser beam output from the resonator is incident and
A photodetector that detects the laser beam that has passed through the absorption cell and outputs a light detection signal.
A differential calculation unit that generates a second derivative signal of the photodetection signal,
An actuator that changes the resonator length of the resonator according to the applied drive voltage, and
Using a laser device including an actuator drive unit that outputs the drive voltage,
A search process in which a singular point is detected based on the second derivative signal while the drive voltage is changed in an increasing direction or a decreasing direction, and the voltage value of the driving voltage at the time when the singular point is detected is stored in a memory. And the search process
A noise discrimination step of discriminating noise from a plurality of the singular points detected in the search step,
When the noise detected as the singularity is present, the driving voltage is changed from a value larger than the voltage value at the time when the noise is detected to an increasing direction, or the driving voltage is changed by the noise. A re-search step of performing the search process while changing from a value smaller than the voltage value at the time of detection to a decreasing direction, and a re-search step.
A laser stabilization method characterized by performing.

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