JPH04260384A - Laser oscillator of automatic line tuning system - Google Patents

Abstract

PURPOSE:To obtain a laser oscillator which is excellent in oscillation wavelength stability and can be easily used at an ordinary industrial level by automatically performing the line tuning to be performed by adjusting the grating of a resonator without making any highly precise manual adjustment. CONSTITUTION:This laser oscillator is provided with a wavelength measuring grating 13 which branches part 8a of the laser light beam emitted from the output mirror 7 of a resonator, detector 15 for detecting the branched light, and arithmetic processing means 17 which inputs signals from the detector 15 through an A/D converter 16 and processes the input signals for judging the presence/absence of a shift in oscillation wavelength. When a is detected in the oscillation wavelength of the laser light, the means 17 calculates a driving amount for correction corresponding to the amount of the shift and sends a signal to a fine driving means 4 to drive a rotating means 3. As a result, the oscillation wavelength is corrected by adjusting the angle of the grating 5 of the resonator.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillator using an automatic line tuning method, and more particularly to the configuration of the laser device and a line tuning method using the laser oscillator.

0003

2. Description of the Related Art Conventionally, as a line tuning method, there is a method in which a grating is used in the configuration of a resonator and a necessary oscillation line is obtained by rotating the grating at a specific angle.

FIG. 3 shows a laser oscillator using such a conventional line tuning method. In FIG. 3, a laser gas is sealed in a chamber 1, and the gas pressure is several atmospheres or more. The main body of the chamber 1 is cylindrical, and the openings at both ends are windows 2a and 2b.
It is sealed with a highly reliable airtight seal. A rotation stage 3 is provided on the rear side of the chamber 1, and is driven by a fine movement drive device 4. On the rotation stage 3, there is a grating 5.
is supported, and the angle of the grating 5 is adjusted by rotating the rotation stage 3. A prism 6 is arranged between the grating 5 and the chamber 1 in order to increase the efficiency of incidence on the grating 5. An output mirror 7, which is a concave mirror, is arranged on the output side of the chamber 1, and together with the grating 5,
It constitutes a resonator.

A beam splitter 9 is provided on the optical axis of the laser beam 8 emitted from the output mirror 7 to split the laser beam 8 into two.
is located. A portion 8a of the laser beam split by the beam splitter 9 is guided to a spectroscope 21 via a mirror 10 and a convex mirror 11 for wavelength measurement. The spectrometer 21 has a convex mirror 22, a grating 23, and a concave mirror 24. Spectrometer 2
A detector 25 is arranged on the emission side of the light emitting device 1 . The signal from the detector 25 is sent to an XY recorder 26, and the XY recorder 26 draws the oscillation wavelength based on the signal from the detector 25.

The operation of the laser oscillator shown in FIG. 3 having the above configuration is as follows. That is, the spectroscope 21 can cause the XY recorder 26 to record the oscillation wavelength by rotating the grating 23 therein. If this oscillation wavelength deviates from the required wavelength, manually operate the fine movement drive device 4, slightly rotate the rotation stage 3, and adjust the angle of the grating 5 of the resonator as necessary. It is possible to obtain a laser output with the desired oscillation wavelength.

[0007]

[Problems to be Solved by the Invention] However, in the conventional laser oscillator as described above, the grating angle of the resonator must be adjusted manually, so the adjustment must be made after detecting the deviation of the oscillation wavelength. Because it takes a certain amount of time to complete the process, it has been difficult to maintain a stable oscillation wavelength. In particular, even if the grating angle is adjusted and fixed once, the oscillation wavelength will shift slightly due to fluctuations in ambient temperature, so in order to keep the oscillation wavelength stable, the grating angle of the resonator must be repeatedly adjusted. have to adjust. Therefore, it is extremely difficult to maintain the oscillation wavelength stably, making it difficult to use it at a general industrial level.

The present invention was proposed to solve the problems of the prior art as described above, and its purpose is to automatically perform line tuning by adjusting the grating of a resonator without performing advanced manual adjustment. The aim is to make it possible to carry out activities in a specific manner. A more general objective is to provide an excellent laser oscillator that has excellent oscillation wavelength stability and can be easily used on a general industrial level by automating such line tuning.

[Configuration of the invention]

0010

[Means for Solving the Problems] The laser oscillator using the automatic line tuning method of the present invention sets the laser gas pressure to a state of several atmospheres or more, and the gain of the laser is set between one wavelength that can oscillate and the next wavelength that can oscillate. In a laser oscillator that performs line tuning between one wavelength that can be oscillated and the next wavelength that can be oscillated; A resonator that performs laser oscillation; Used as a component of the resonator and that performs line tuning by changing the angle. a grating for the resonator; a grating for wavelength measurement that is placed outside the resonator and separates the laser output light output from the resonator; a detector that detects the spectra of the laser output light; and a scanning mechanism. , an A/D converter connected to the detector; an arithmetic processing means connected to the A/D converter and inputting a signal from the detector through the A/D converter and processing the data; A rotating means for supporting the grating and changing the angle of the grating of the resonator by rotation; and a fine movement driving means for driving the rotating means by a signal from the arithmetic processing means and changing the angle of the grating of the resonator. There is.

[0011]

[Operation] The operation of the laser oscillator of the present invention having the above structure is as follows. That is, the laser output light output from the resonator is separated into spectra by a grating for wavelength measurement, and detected by a detector. The signal from the detector is digitized by an A/D converter and then input to the arithmetic processing means. The arithmetic processing means processes this input signal and determines whether there is a shift in the oscillation wavelength. If there is a deviation, a correction driving amount of the rotation means is calculated according to the amount of deviation, a signal is sent to the fine movement drive means, the rotation means is driven, and the angle of the grating of the resonator is adjusted. Adjust and correct the oscillation wavelength. Therefore, according to the present invention, line tuning by grating adjustment of a resonator can be automatically performed without performing sophisticated manual adjustment.

0012

[Embodiment] An embodiment of a laser oscillator using an automatic line tuning method according to the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained in detail with reference to . In this case, FIG. 1 is a schematic configuration diagram showing the entire laser oscillator, and FIG. 2 is a curve diagram showing the intensity distribution of the laser appearing on a wavelength measurement detector. Note that the same parts as those in the prior art shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, a beam splitter 9 is arranged on the optical axis of the laser beam 8 emitted from the output mirror 7 to reflect and split a part of the laser beam 8a. (Part of laser beam) 8a
A mirror 10 is placed on the optical axis of
A first convex mirror 1 that narrows down the laser beam reflected by
1 was placed. A second convex mirror 12 expands the laser beam narrowed down by the first convex mirror 11, and a grating 1 for wavelength measurement separates the expanded laser beam.
3 and a concave mirror 14 for narrowing down the laser beam again were disposed in sequence, and a pyro array (detector) 15 was further disposed near the focal point of the concave mirror 14. More specifically, 256 pyro elements are used as the pyro array (detector) 15, and these pyro elements are arranged on a straight line intersecting the traveling direction of the light from the concave mirror 14 to form the pyro array 1.
5 was constructed. Then, each pyro element constituting this pyro array 15 is connected to an A equipped with a scanning mechanism.
/D converter 16, computer (arithmetic processing means) 17
connected to. According to the present invention, the computer (arithmetic processing means) 17 connects the rotating stage (
This is a device that sends a signal to the fine movement drive device (fine movement drive means) 4 of the rotating means) 3 to drive the fine movement drive device 4. In addition,
As the fine movement drive device 4, a pulse-driven micrometer was used.

The intensity of the laser light appearing on the pyroarray 15 is strong at a specific wavelength due to the grating 13 for wavelength measurement, and becomes weaker as it deviates from that wavelength. FIG. 2 shows an intensity distribution curve 19 of laser light appearing on such a pyro array 15. In this case, since it is not possible to determine the peak value of the intensity distribution of the laser beam with this intensity distribution curve 19 as it is, the intensity distribution of the laser beam is first converted into a Lorentzian curve 20 by the computer 17.
Settings were made to determine the peak value of the intensity distribution of the laser beam. Further, the number of pulses for rotating the rotary stage 3 by driving the pulse-driven micrometer, which is the fine movement drive device 4, by an amount corresponding to the deviation of the peak value was preset in the calculator 17.

The operation of the laser oscillator of this embodiment having the above configuration is as follows. First, a portion 8a of the laser beam emitted from the output mirror 7 of the resonator is reflected and split by the beam splitter 9. A portion 8a of this laser beam is reflected by a mirror 10, narrowed down by a first convex mirror 11, magnified by a second convex mirror 12, separated into spectra by a grating 13 for wavelength measurement, and finally separated by a concave mirror 11. 14 onto the pyro array 15. In this case, since the reflection angle of the laser beam differs depending on the wavelength due to the diffraction effect of the grating 13, the laser beam spreads on the pyroarray 15 with an intensity distribution corresponding to the resolution of wavelength measurement. That is, an intensity distribution as shown in FIG. 2 appears. Such intensity distribution on the pyro array 15 is sequentially transferred to the computer 17 via an A/D converter 16 equipped with a scanning mechanism. The computer 17 converts the input laser beam intensity distribution data into a Lorentzian curve as shown in FIG. 2, and determines the peak value of the laser beam intensity distribution. The calculator 17 compares the position of this peak value with the position of the previous peak value, and if it differs from the position of the previous peak value, calculates a specified number of pulses corresponding to the amount of the deviation by the amount of the position deviation. The signal is sent to a pulse-driven micrometer, which is a fine movement drive device 4. As a result, the pulse-driven micrometer that is the fine movement drive device 4 is driven, the rotation stage 3 is rotated by an appropriate angle, the angle of the grating 5 of the resonator is appropriately adjusted, and the wavelength of the oscillated light is kept at a constant value. It is maintained.

As described above, according to the present embodiment, line tuning by adjusting the grating of the resonator can be automatically and easily performed without the need for sophisticated manual adjustment as in the prior art. Therefore, since the deviation in the oscillation wavelength can be corrected immediately upon detection, the stability of the oscillation wavelength can be significantly improved compared to the conventional technique.

Note that the present invention is not limited to the embodiments described above, and the configuration of the detector for wavelength measurement can be freely changed. Furthermore, the arrangement of gratings and detectors for wavelength measurement can be changed freely; for example,
The wavelength measurement grating can be rotated so that the laser beam is always incident on a single detector, or the wavelength measurement grating can be fixed and a single detector can be moved at equal intervals. It is possible. Further, the configuration of the fine movement driving means can also be changed as appropriate.

[0018]

As described above, according to the present invention, a wavelength measurement grating, a detector, an A/D converter, and an arithmetic processing means are used to automatically detect a wavelength shift. Since the fine movement drive means is driven based on the data and the rotation means is rotated to automatically adjust the angle deviation of the grating of the resonator, line tuning can be performed automatically. And, by automating line tuning like this, the oscillation wavelength is excellent in stability,
It is possible to provide an excellent laser oscillator that can be easily used at a general industrial level.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a laser oscillator using an automatic line tuning method according to the present invention.

FIG. 2 is a curve diagram showing the intensity distribution of the laser appearing on a wavelength measurement detector in the laser oscillator of FIG. 1;

FIG. 3 is a schematic configuration diagram showing an example of a laser oscillator using a conventional line tuning method.

[Explanation of symbols]

1 Chambers 2a, 2b Window 3 Rotation stage (rotation means) 4 Fine movement drive device (fine movement drive means) 5 Resonator grating 6 Prism 7 Output mirror 8 Laser light 8a Part of laser light 9 Beam splitter 10 Mirror 11 First Convex mirror 12 Second convex mirror 13 Grating 14 for wavelength measurement
Concave mirror 15 Pyro array (detector) 16
A/D converter 17 Computer (arithmetic processing means) 18 Interface 19 Laser light intensity distribution curve 20 Lorentzian curve 21 Spectrometer 22 Convex mirror 23 Grating 24 Concave mirror 25 Detector 26 XY recorder

Claims (1)

[Claims] Claim 1: The laser gas pressure is set to several atmospheres or more, and the gain of the laser is obtained between the wavelength that can oscillate and the next wavelength that can oscillate. In a laser oscillator, line tuning is performed between the resonator that performs laser oscillation, the grating of the resonator that is used as a component of the resonator and performs line tuning by changing the angle, and the A grating for wavelength measurement that separates the laser output light output from the device, a detector that detects the spectrum of the laser output light, an A/D converter equipped with a scanning mechanism and connected to the detector, and an A/D converter that includes a scanning mechanism and is connected to the detector. A calculation processing means that is connected to the converter and inputs a signal from the detector through the A/D converter and processes the data; and a rotation means that supports the grating of the resonator and changes the angle of the grating of the resonator by rotation. 1. A laser oscillator using an automatic line tuning method, characterized in that the laser oscillator has a fine movement drive means for driving the rotation means in response to a signal from the arithmetic processing means and changing the angle of a grating of a resonator.