JP2792457B2 - Microwave-excited gas laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device, and more particularly to a microwave-excited gas laser device.

[0002]

2. Description of the Related Art In general, a discharge-excited gas laser device is required to generate a spatially uniform glow discharge in a laser medium gas.

[0003] The non-uniformity of the discharge induces an arc discharge that is not suitable for excitation, causes partial abnormal heating of gas, and causes a spatial non-uniformity of the laser amplification factor. This is because, overall, it causes a decrease in the laser oscillation efficiency and a decrease in the maximum output.

However, in the case of discharge excitation using microwaves, since the wavelength of microwaves is as short as ten and several centimeters, a uniform electric field intensity distribution cannot be obtained in a wide range, and there is a problem that the excitation becomes spatially nonuniform. Therefore, it is particularly difficult to make the discharge spatially uniform.

As a countermeasure against this, for example, Japanese Patent Laid-Open No.
According to Japanese Patent No. 0975, an insulator is inserted inside the microwave waveguide to improve the spatial uniformity of the microwave electric field.

However, this configuration is only an improvement in that the range of the discharge region is limited by an insulator and a portion having relatively good electric field uniformity is used, and an essentially uniform electric field intensity distribution is obtained. It is not a proposal to create.

Therefore, the present applicant has filed Japanese Patent Application No. 7-2941.
No. 5 proposed an orthogonal waveguide as shown in FIGS. 8 and 9 and succeeded in achieving a uniform electric field intensity distribution in the radial direction of the laser tube.

FIG. 8 is a configuration diagram of an orthogonal waveguide, and FIG.
FIG. 9 is a cross-sectional view taken along a plane including the x-axis and the y-axis in FIG. 8.

8 and 9, 910 is a cavity resonator, 911 and 912 are microwave oscillators, 913 and 91.
4 is a waveguide, 915 is a laser tube, 916 is an output mirror, 91
7 is a total reflection mirror, 918 to 921 are plungers, 92
Reference numerals 2 and 923 denote matching units each having three stub tuners.

Further, reference numerals 924 and 925 denote antennas of the microwave oscillators 911 and 912, and reference numeral 926 denotes an electric field intensity distribution of microwaves generated by the microwave oscillator 911 in the y direction.
Reference numeral 927 denotes an electric field intensity distribution of a microwave in the x direction generated by the microwave oscillator 912, and reference numeral 929 denotes a laser medium gas.

First, as shown in FIGS. 8 and 9, microwaves (oscillation frequencies of 2.45 GHz ± 0.1 GHz, respectively) generated from microwave oscillators 911 and 912 propagate through waveguides 913 and 914. , Are matched by matching units 922 and 923.

Here, the waveguides 913 and 914 intersect each other at the position of the laser tube 915, but are particularly orthogonal here.

At the position of the laser tube 915, the microwaves from the microwave oscillator 911 and the microwave oscillator 912 have the electric field directions orthogonal to each other.

Therefore, the two microwave oscillators 911 and 911
Microwaves oscillated from 912 have traveling directions orthogonal to each other, and their electric field oscillation directions (directions of electric field vectors) are also orthogonal to each other.

The laser medium gas 929 in the laser tube 915 is generated by the two orthogonal microwave electric fields.
(A mixture gas of CO 2, N 2, and He at a ratio of 4:24:72 and a pressure of about 60 Torr) is excited by discharge, and the total reflection mirror 9 is excited.
Laser light is output in the z-axis direction from an optical resonator constituted by the output mirror 17 and the output mirror 916.

Here, with respect to the microwave, y in FIG.
As shown by the directional electric field distribution 926 and the x-directional electric field distribution 927, the plungers 918, 919, 920, and 921 are moved and adjusted so that the laser tube 915 is located at the antinode of the standing wave.

The electric field intensity required for starting discharge is about 1 k
However, in the case of a traveling wave of a microwave of 1 kW, the electric field intensity is about 500 V / cm at the maximum, which is insufficient for the start of discharge. Therefore, the microwave is used as a standing wave, and the position of the antinode where the electric field intensity is strongest is adjusted so as to coincide with the laser tube 915, thereby making it easier to start the discharge.

The matching units 922 and 923 adjust the microwave oscillators 911 and 912 to an optimal matching state with the discharge load.

Although not explicitly shown in FIG. 8, the laser medium gas 929 is provided with a gas cooling circulating mechanism that is drawn out of the laser tube 915 by a pipe and injected again by a pump after cooling. Then, the laser medium gas 92
A description will be given of a high-speed axial flow laser device in which the laser beam 9 flows at a high speed in the laser tube 915.

Now, referring to FIG.
When 11 and 912 oscillate simultaneously, the laser tube 915
, An electric field in the x direction and an electric field in the y direction are simultaneously applied.

Since the microwave oscillators 911 and 912 are separate microwave oscillators, they do not oscillate exactly at the same frequency even when oscillating at 2.45 GHz, and there is a difference in oscillation frequency of several MHz or more.

When the vibration frequencies of the two electric fields are different, the phase difference δ changes with time. At this time, the locus drawn by the combined vector of the electric field vector in the x direction and the electric field vector in the y direction repeats a circle-ellipse-straight line-ellipse-circle as δ changes.

The repetition frequency corresponds to the difference frequency between two different oscillation frequencies. That is, the combined electric field is the frequency of the corresponding microwave (2.4 GHz in this embodiment).
To 2.5 GHz), and furthermore, this rotation has a difference frequency between two different frequencies (up to 0.1 GHz).
The state changes in z).

The direction of the combined electric field extends in all directions in the two-dimensional space corresponding to the difference frequency between the oscillation frequencies, so that the discharge region spreads two-dimensionally as a whole and has a substantially circular cross section. A uniform discharge region is realized.

However, when the discharge in the radial direction of the laser tube is made uniform as described above, a phenomenon occurs in which the discharge gradually concentrates on the wall of the laser tube 915 as the microwave input increases.

FIG. 10 is a schematic diagram of the luminance distribution in the laser tube radial direction.
(B) and (c), where o indicates the central position of the tube and p indicates the position of the tube wall.

The reason for the concentration of the electric discharge on the tube wall is that the microwave electric field tends to concentrate on the laser tube because the laser tube is made of a dielectric material, and the tendency is further strengthened as the microwave input increases.

FIG. 10C shows a state in which this concentration phenomenon has progressed most, and the discharge exists only on the tube wall.

In such a state, sufficient laser oscillation cannot be obtained. Furthermore, since there is no control means for the discharge in the axial direction, the unstable discharge phenomenon described below occurs.

FIG. 11A is a diagram showing the microwave electric field intensity distribution in the z direction in the waveguide and the position of the discharge gas at that time.

Here, 930 is the gas flow direction, 931 is the leeward area, 932 is the leeward area, 933 is the electric field intensity distribution in the z direction, and 934 is the discharge gas.

In this case, the maximum intensity position of the electric field in the z direction is located at the center of the waveguide, and as a result, the electric field intensity distribution 93
0 is a symmetric sinusoidal distribution to the left and right.

The discharge gas 934 is located near the center of the waveguide where the maximum intensity position of the electric field exists.

FIG. 11B is a diagram showing the microwave electric field intensity distribution in the z direction and the position of the discharge gas when a certain time Δt has elapsed from the moment shown in FIG. 11A.

Here, 935 is the electric field intensity distribution in the z direction,
936 indicates a discharge gas. FIG. 11B is replaced with FIG.
The electric field intensity distribution 933 is compared with the electric field intensity distribution 935
Is exactly the same as
It can be seen that the discharge gas 934 moves downwind due to the gas flow and becomes a discharge gas 936.

The normal discharge gas 936 is heated and expanded in the process of moving, and is in a state of easily absorbing microwave energy.

Consider a case where a new discharge occurs in the state shown in FIG. Here, considering the discharge, the discharge is about to occur at the position where the electric field intensity is maximum, but a discharge gas 936 that easily absorbs microwave exists near the leeward side of the electric field intensity maximum position. In addition, since the electric field strength there is relatively large, there are two places where discharge is likely to occur, and the newly generated discharge is extremely unstable in position. .

The change in the discharge state as described above leads to a deterioration in the laser output, and is not desirable when a high and stable laser output is required. Is the property required.

[0039]

That is, in the conventional configuration, the discharge in the radial direction of the laser tube is concentrated on the wall of the laser tube, so that there is a problem that the efficiency and output of laser oscillation decrease.

Furthermore, since the discharge in the axial direction of the laser tube is unstable in position, the laser output also becomes unstable.

The present invention solves the above-mentioned conventional problems, and provides a stable microwave-excited gas laser device which has a large laser oscillation efficiency and output power by controlling the intensity distribution of an electric field in a laser tube radial direction and an axial direction. The purpose is to provide.

[0042]

In order to solve the above-mentioned problems, the present invention is directed to a microwave that discharges and excites a laser medium gas in a discharge tube provided in a waveguide with a microwave to perform laser oscillation. An excitation gas laser device, comprising an electric field intensity distribution control means for controlling an intensity distribution of an electric field generated by the microwave.

Further, the microwave-excited gas laser device is a high-speed axial-flow gas laser device in which the gas medium to be excited can flow at a high speed in the laser tube. The electric field intensity change rate in the tube axis direction on the leeward side of the gas medium flow when divided is the windward of the gas medium flow when the laser tube is bisected in the tube axis direction by the electric field intensity distribution control means. The microwave-excited gas laser device may have at least one location where the rate of change in electric field intensity in the tube axis direction is greater than the above.

The microwave-excited gas laser device is a high-speed axial flow gas laser device in which the gas medium to be excited can flow at a high speed in the laser tube. The electric field intensity distribution control means controls the electric field in the axial direction of the laser tube. It is preferable that the maximum intensity position of the intensity distribution be located on the leeward side of the gas medium flow when the laser tube is bisected in the tube axis direction.

In this case, the electric field intensity distribution control means includes:
It may be a conductive member. Preferably, there are a plurality of conductive members, and their potentials are substantially equal to each other.

On the other hand, it is preferable that the electric field intensity distribution control means removes an electric field unnecessary for discharge in the laser tube containing the gas medium to be excited.

In this case, the electric field intensity distribution control means includes:
A conductor tube having a shape surrounding the laser tube may be used.

Further, the waveguide for guiding the microwave is an intersecting waveguide having an intersection where the microwaves intersect, and the radial electric field of the laser tube in which the gas medium to be excited is stored. A microwave-excited gas laser device may be characterized in that the intensity distribution is controlled by the electric field intensity distribution control means.

In this case, the electric field intensity distribution control means:
Preferably, it is a conductive member. Preferably, there are a plurality of the conductive members, and their potentials are substantially equal to each other.

Further, the laser medium gas may be a microwave-excited gas laser device containing a CO 2 gas.

[0051]

With the above arrangement, a stable microwave discharge can be obtained in both the radial direction and the axial direction, and high-efficiency, high-output and stable laser oscillation can be obtained.

[0052]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an orthogonal waveguide showing a first embodiment of the present invention. In FIG. 1, 10 is a cavity resonator, 11 and 12 are microwave oscillators, 13 and 14 are waveguides, 15 is a laser tube, 18 to 21 are plungers, 2
Reference numerals 2 and 23 denote matching units each having three stub tuners.

Further, 24 and 25 are microwave oscillators 1
Antennas 1 and 12, 26 are electric field intensity distributions of microwaves in the y direction generated by the microwave oscillator 11, 27 are electric field intensity distributions of microwaves in the x direction generated by the microwave oscillator 12, and 29 is a laser medium gas. , 30 are conductive members which are electrically connected to the bottom and side surfaces of the waveguide while being symmetrically arranged around the laser tube, and which are installed at substantially equal potentials.

FIG. 2 is a partial view in which the inside of the waveguide 13 in FIG. 1 is projected in the lateral direction. In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, 31 is a discharge, 32 is a leeward area, 33 is a leeward area, 34 is a gas flow direction, 39 is a length of a conductive member, and 40 is a length of a conductive member. This is the thickness of the conductive member.

In the microwave-excited gas laser apparatus configured as described above, CO 2, which particularly requires a large output,
The following operation will be described assuming a laser device, but it goes without saying that if the laser medium gas is changed, it will also function as another type of gas laser. For example, CO gas laser, N2 gas laser, rare gas laser, metal vapor laser,
It is also applicable to a He-Ne laser, an ion laser, and the like.

In FIG. 1, the operations in the vertical direction and the horizontal direction are basically the same. Therefore, only the waveguide 13 will be described here.

As shown in FIG. 1, the microwave oscillator 11
Microwave (2.45 GHz ± 0.05 G)
Hz) propagates through the waveguide 13 via the antenna 24, is matched by the matching unit 22, and has a laser medium gas 29 (a mixed gas of CO2, N2, and He in the laser tube 15 at a ratio of 4: 24:72 at a pressure of about 60 Torr) and discharge excitation, and a laser beam is output from optical resonators, which are not shown, which are provided at both ends of the laser tube 15 and are composed of a total reflection mirror and an output mirror.

Although not shown, the laser medium gas 29 is circulated in a closed conduit including the laser tube 15 by a fan.

As for the microwave, the plungers 18 and 19 are adjusted such that the antinode position of the microwave standing wave comes to the laser tube 15 as shown in FIG.

Further, the matching unit 22 includes the microwave oscillator 1
The microwave output from 1 is adjusted so as to be optimally matched with the load of the laser tube 15 and the load of the discharge 31 due to the electric field controlled by the conductive member 30.

The control of the electric field intensity distribution by the conductive member 30 is changed by changing the length 39 and the thickness 40 of the conductive member.

Hereinafter, the conductive member 3 in this embodiment will be described.
The effect of 0 will be described in detail.

FIG. 3A is a diagram showing the microwave electric field intensity distribution in the z direction in the waveguide and the position of the discharge gas at that time in FIG.

Here, 35 is the electric field intensity distribution in the z direction, and 36 is
Indicates a discharge gas. Since the conductive member 30 is located in the leeward region 33, the maximum intensity position of the electric field moves to the leeward side, and the electric field intensity distribution 35 has a distribution shape that is asymmetrical left and right and leans downwindward.

The discharge gas 36 is located in the leeward area 33 where the maximum intensity position of the electric field exists. FIG.
(B) shows a certain time Δt from a certain moment shown in FIG.
FIG. 7 is a diagram showing a microwave electric field intensity distribution in the z direction and a position of a discharge gas when a time elapses.

Here, 37 is the electric field intensity distribution in the z direction, 38
Indicates a discharge gas. 3B is compared with FIG. 3A, the electric field intensity distribution 37 is exactly the same as the electric field intensity distribution 35, but the discharge gas 36
Is moved downwind by the gas flow and becomes a discharge gas 38.

In FIG. 3B, since the gradient of the electric field intensity distribution 37 in the leeward region 33 is large, that is, the electric field intensity change rate is large, the electric field intensity at the portion where the discharge gas 38 is located is lower than that of the conventional example. The electric field strength 935 in FIG. 11B described in FIG.

Consider a case where a new discharge occurs in such a state. Discharge is to occur at the position where the electric field intensity is maximum, but the discharge gas 38 that easily absorbs microwaves is present near the leeward side of the electric field intensity maximum position, as in the conventional example. is there.

However, since the electric field intensity there is reduced, a new discharge is surely generated at the position where the electric field intensity is maximum, and a positionally stable discharge can be obtained.

As described above, by controlling the electric field intensity distribution in the axial direction of the laser tube by the conductive member, a stable discharge can be realized.

Hereinafter, the details of the confirmation experiment performed by the present inventors will be described. The dimension of the waveguide section in the z direction is 95 mm, and the dimension in the y direction is 45 mm.

The material of the conductive member 30 was aluminum having a length 40 of 40 mm and a thickness 39 of 10 mm.

The inside diameter of the laser tube 15 is 25 mm and the outside diameter is 28 mm, and the laser medium gas flows through the inside of the tube at about 300 m / m.
Flowing at s.

Under these conditions, the laser medium gas was discharge-excited by microwaves, and laser oscillation was performed. If no control was performed, microwave input was 1070 W (laser output 205 W, oscillation efficiency 19.2%). Although the output was saturated, the control by the conductive member enabled the microwave input 1445 W (laser output 273 W,
The output saturation input value was improved up to the oscillation efficiency of 18.9%).

By the way, the effect of the conductive member is not only to control the electric field intensity distribution in the axial direction described in this embodiment, but also to
As described later, it also has a role of controlling the radial electric field intensity distribution.

Therefore, the improvement of the laser output saturation value due to the use of the conductive member is considered to be a synergistic effect with the control of the electric field intensity distribution in the radial direction of the conductive member described in detail in the third embodiment.

In this embodiment, as shown in FIG. 1 and FIG. 2, four conductive members are used obliquely at 45 degrees so as to be symmetrically arranged around the laser tube. It is needless to say that the same effect as that described in the present embodiment can be obtained even if a conductive member having an asymmetrical arrangement is used around the periphery.

Further, it is needless to say that the same effect as that described in the present embodiment can be obtained even if the conductive members are disposed at the upper, lower, left and right sides of the laser tube.

Further, the number of conductive members may be 1
It is a matter of course that the same effects as those described in the present embodiment can be obtained even when the number is three or more or five or more.

Although the present embodiment has been described using an orthogonal waveguide, it goes without saying that a similar effect can be obtained in any type of waveguide.

The effect of the waveguide is the same in the following embodiments.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a partial sectional view of an orthogonal waveguide according to a second embodiment of the present invention, and corresponds to FIG. 1 of the first embodiment.

FIG. 5 is a partial view in which the inside of the waveguide 13 in FIG. 4 is projected in the lateral direction, and corresponds to FIG. 2 of the first embodiment.

In FIGS. 4 and 5, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals.
Is a discharge, 58 is a length of the conductor tube, and 59 is a diameter of the conductor tube.

In this embodiment, a straight cylinder is used as a typical shape of the conductor tube. The device of the present embodiment configured as described above is different from the device of the first embodiment only in that the conductor tube 50 is arranged around the laser tube instead of the conductive member 30. Are exactly the same.

The control of the electric field distribution by the conductor tube 50 is changed by changing the length 58 and the diameter 59 of the conductor tube.

The basic operation leading to the generation of the microwave discharge is exactly the same as that of the first embodiment, and the effect of the conductor tube 50 in this embodiment will be described in detail below.

FIG. 6A is a diagram showing the microwave electric field intensity distribution in the z direction in the waveguide and the position of the discharge gas at that time in FIG.

Here, 52 indicates the electric field intensity distribution inside the conductor cylinder in the z direction, 53 indicates the electric field distribution outside the conductor cylinder in the z direction, and 54 indicates the discharge gas.

As shown in FIGS. 11A and 11B, the electric field intensity distribution 53 outside the conductor tube has the maximum electric field intensity position in the z direction located at the center of the waveguide and is symmetrical left and right. Sine wave distribution.

On the other hand, the electric field intensity distribution 52 inside the conductor tube
When the diameter 59 of the conductor tube is shorter than the cut-off wavelength of the microwave, the microwave cannot enter the inside of the conductor tube 50. The distribution is the same as the electric field strength, and the electric field does not exist inside.

The discharge gas 54 is located near the center of the waveguide where the position of the maximum intensity of the electric field exists.

FIG. 6B is a diagram showing the microwave electric field intensity distribution in the z direction and the position of the discharge gas when a certain time Δt has elapsed from the moment shown in FIG. 6A.

Here, 55 indicates the electric field intensity distribution inside the conductor cylinder in the z direction, 56 indicates the electric field intensity distribution outside the conductor cylinder in the z direction, and 57 indicates the discharge gas.

FIG. 6B is different from FIG. 6A in that the electric field intensity distributions 55 and 56 are exactly the same as the electric field intensity distributions 52 and 53, but the discharge gas 54 Is moved downwind by the gas flow and becomes a discharge gas 57.

In FIG. 6B, at the entrance of the conductor tube 50, the electric field discontinuously disappears (that is, the rate of change of the electric field intensity is infinite). , Almost unaffected.

Consider a case where a new discharge occurs in such a state. Although the discharge is to be generated at the position where the electric field intensity is maximum, the discharge gas 57 which easily absorbs the microwave exists near the leeward side of the electric field intensity maximum position, as in the related art. .

However, the influence of the electric field on the discharge gas 57 is as follows:
Since the discharge is hardly affected, a new discharge is surely generated at the maximum electric field intensity position, and a positionally stable discharge can be obtained.

As described above, a stable discharge can be realized by removing an unnecessary electric field by the conductor tube 50.

An experiment was conducted under the following conditions.
The effect of the conductive member was confirmed. The dimension in the z direction of the waveguide section is 95 mm, and the dimension in the y direction is 45 m, as in Example 1.
m.

The material of the conductor tube 50 was aluminum, having a length 58 of 30 mm and a diameter 59 of 30 mm.

The laser tube 15 has an inner diameter of 25 mm and an outer diameter of 28 mm, and the laser medium gas flows through the inside of the tube at about 300 m / cm.
Flowing at s.

Under these conditions, the laser medium gas was discharge-excited by microwaves and laser oscillation was performed. If no control was performed, the microwave input was 1070 W (laser output 205 W, oscillation efficiency 19.2%). Although the output was saturated, the control was performed by the conductor tube to obtain a microwave input 1282W (laser output 242W,
The output saturation input value was improved up to the oscillation efficiency of 18.9%).

In the present embodiment, a straight cylinder is used as the shape of the conductor tube. However, a square tube, a tapered tube, a tube obtained by combining a straight tube and a tapered tube, or the like may be used.

In this embodiment, the case where the conductor tube is provided only in the leeward region has been described. However, if the purpose is to remove an unnecessary electric field, the conductor tube may be provided in the leeward region. It goes without saying that the same effect may be obtained even if the conductor tube is provided.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described in detail with reference to the drawings.

In this embodiment, consideration will be given based on the configuration of FIG. In the first embodiment, as an effect of the conductive member 30, the control of the electric field intensity distribution in the laser tube axial direction by the conductive member has been described to realize a stable discharge.

Here, another effect of the conductive member 30 will be described in detail below.

In the conventional example, the discharge in the state shown in FIG. 9 in which the conductive member does not exist around the laser tube is basically a uniform discharge region having a circular cross section. However, in this case, since the laser tube is a dielectric, the electric field concentrates on the wall of the laser tube, and as a result, the discharge also concentrates on the wall of the laser tube, so that sufficient laser oscillation cannot be obtained.

FIG. 7 is a partially enlarged view of the periphery of the laser tube of FIG. In FIG. 7, the same portions as those in the above-mentioned drawings are denoted by the same reference numerals, but reference numeral 60 denotes an edge portion of the conductive member, 61 denotes discharge, and 62 denotes strong discharge.

It is known that the lines of electric force are usually concentrated on a portion having a sharp shape. In the case of this embodiment, the microwave electric field is concentrated on the edge 60 of the conductive member 30.

Therefore, the microwave electric field applied to the inside of the laser tube 15 is strong at the upper right, lower right, upper left, and lower left of the laser tube radial plane.

Accordingly, a strong discharge 62 is generated inside the discharge 61 at a position where the electric field intensity is strong.

In such a configuration, it was confirmed that when a strong discharge location was formed in a part of the tube wall, the concentration of discharge on the entire tube wall was reduced.

This is considered to be due to the following reasons. A discharge state having a cross section as shown in FIG.
That is, in a state where the discharge exists only on the wall surface of the laser tube, the discharge itself plays a role similar to the conductor tube described in the second embodiment, and the microwave electric field cannot reach the center of the laser tube. .

This phenomenon occurs because the discharge is uniformly concentrated on the tube wall. Therefore, if a measure is taken such that the microwave electric field concentrates on a part of the tube wall, the discharge is not uniformly generated on the tube wall, but is concentrated on a portion where the electric field is concentrated.

The rate at which the microwave electric field is hindered by the discharge itself is reduced, and the microwave electric field can reach the center of the laser tube.

As described above, by controlling the electric field intensity distribution in the laser tube radial direction by the conductive member, it is possible to suppress the uniform concentration of discharge on the tube wall.

Therefore, an experiment was conducted under the following conditions,
The effect of the conductive member was confirmed. The material of the conductive member 30 is aluminum, the length 40 is 40 mm, and the thickness 39 is 10 mm.
Was used.

The laser tube 15 has an inner diameter of 25 mm and an outer diameter of 28 mm, and the laser medium gas flows through the inside of the tube at about 300 m / cm.
Flowing at s.

Under these conditions, the laser medium gas was discharge-excited by microwaves, and laser oscillation was performed. If no control was performed, microwave input was 1070 W (laser output 205 W, oscillation efficiency 19.2%). Although the output was saturated, the control by the conductive member enabled the microwave input 1445 W (laser output 273 W,
The output saturation input value was improved up to the oscillation efficiency of 18.9%).

When controlling the strong discharge 62,
By changing the thickness 39 of the conductive member, the conductive member edge 6
The distance between 0 and the laser tube 15 may be adjusted.

The sharper the conductive member edge portion 60, the stronger the strong discharge 62, and the weaker the strong discharge 62 as it becomes duller.

In this embodiment, as shown in FIGS. 1 and 7, a symmetrical arrangement around the laser tube is adopted.
Although four conductive members are used obliquely at 45 degrees, the same effect as that described in the present embodiment can be obtained by using a conductive member that is asymmetrically arranged around the laser tube. Not even.

Further, it is a matter of course that the same effect as that described in the present embodiment can be obtained even if the conductive members are disposed on the upper, lower, left and right sides of the laser tube.

Further, the number of conductive members may be 1
It is a matter of course that the same effect as that described in the present embodiment can be obtained even when the number is three or more or five or more.

In all of the above embodiments, the waveguide may be a rectangular waveguide or a cylindrical waveguide.

The microwave propagating in the rectangular waveguide is in the TEm0 mode, and the microwave propagating in the cylindrical waveguide is in the TE11 mode.

In all the embodiments described above, the matching unit can take any form of a two-stub tuner, a three-stub tuner, and an EH tuner.

In all of the above embodiments, the cavity resonator is preferably made of a metal conductor as a base material.

In all of the above embodiments, it is preferable that the laser tube be made of a dielectric material that transmits microwaves.

For this dielectric, quartz glass, heat-resistant tempered glass, alumina or the like can be used.

In all of the above embodiments, a magnetron can be suitably used as a microwave oscillator.

In all of the above embodiments, the laser medium gas can contain at least one of CO gas, CO 2 gas, N 2 gas, metal vapor, rare gas, and halogen gas.

In all of the above embodiments, the laser medium gas can be circulated by a gas circulator system including a laser tube, a gas circulation pump, a heat exchanger, and gas piping.

[0138]

As described above, according to the present invention, the stabilization of the discharge can be realized by using the electric field intensity distribution control means around the laser tube installed inside the waveguide.

As a result, it is possible to realize a microwave-excited gas laser device capable of performing stable laser oscillation with high output and high efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a partial projection view of the inside of the waveguide according to the first embodiment;

FIG. 3 is a diagram showing a microwave electric field intensity distribution and a discharge gas position inside the waveguide according to the first embodiment.

FIG. 4 is a sectional view of the second embodiment.

FIG. 5 is a partial projection view of the inside of the waveguide according to the second embodiment.

FIG. 6 is a diagram showing a microwave electric field intensity distribution and a discharge gas position inside the waveguide of the second embodiment.

FIG. 7 is an enlarged cross-sectional view of a portion around a laser tube according to the third embodiment.

FIG. 8 is a perspective view of a conventional device.

FIG. 9 is a sectional view of a conventional device.

FIG. 10 is a schematic diagram of a laser tube radial direction discharge luminance distribution according to a conventional technique.

FIG. 11 is a diagram showing a microwave electric field intensity distribution and a discharge gas position inside a waveguide according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 10 cavity resonator 11 microwave oscillator 12 microwave oscillator 13 waveguide 14 waveguide 15 laser tube 18 plunger 19 plunger 20 plunger 21 plunger 22 matching device 23 matching device 24 antenna 25 antenna 26 y direction electric field intensity distribution 27 x direction Electric field intensity distribution 29 Laser medium gas 30 Conductive member 31 Discharge 32 Upwind area 33 Downwind area 34 Gas flow direction 35 Z direction electric field intensity distribution 36 Discharge gas 37 z direction electric field intensity distribution 38 Discharge gas 50 Conductor tube 51 Discharge 52 Conduction In-body z-direction electric field strength distribution 53 Conductor outside-cylinder z-direction electric field strength distribution 54 Discharge gas 55 Conductor inside-cylinder z-direction electric field strength distribution 56 Out-of-conductor tube z-direction electric field strength distribution 57 Discharge gas 60 Conductive member edge 61 Discharge 62 Strong discharge 910 Cavity resonator 911 My B oscillator 912 Microwave oscillator 913 Waveguide 914 Waveguide 915 Laser tube 916 Output mirror 917 Total reflection mirror 918 Plunger 919 Plunger 920 Plunger 921 Plunger 922 Matching device 923 Matching device 924 Antenna 925 Antenna 926 Y-direction electric field intensity distribution 927 x direction electric field intensity distribution 929 laser medium gas 930 gas flow direction 931 leeward area 932 leeward area 933 z direction electric field intensity distribution 934 discharge gas 935 z direction electric field intensity distribution 936 discharge gas

──────────────────────────────────────────────────続 き Continued on the front page (72) Minoru Kimura 3-10-1, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (56) References JP-A-2-246178 (JP, A) JP-A-2-237181 (JP, A) JP-A-2-288382 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/097-3/0979

Claims (8)

(57) [Claims] 1. A microwave-excited gas laser apparatus for performing laser oscillation by discharge-exciting a laser medium gas in a laser tube provided in a waveguide by microwaves introduced into the waveguide, wherein and the electric field intensity distribution control means for controlling the electric field intensity distribution of the generated by the wave, the excitation
Means for flowing a gas medium at a high speed into a laser tube;
Gas medium when the laser tube in the tube is bisected in the axial direction of the tube
Electric field intensity change rate in the tube axis direction of the laser tube on the leeward side of the flow
The laser tube is controlled by electric field intensity distribution control means.
The pipe on the windward side of the gaseous medium flow when bisected in the axial direction
There are few places that are greater than the rate of change of the electric field strength in the axial direction.
Microwave-excited gas laser device with only one location 2. A laser medium in a laser tube provided in a waveguide.
Gas is discharged by microwaves introduced into the waveguide.
A microwave-excited gas laser that excites and performs laser oscillation
An electric field generated by the microwave.
Means for controlling the intensity distribution of the laser beam
Means for flowing in a tube at high speed, and means for controlling electric field intensity distribution
The maximum of the electric field intensity distribution in the tube axis direction of the laser tube
When the intensity position bisects the laser tube in the tube axis direction
A microwave-excited gas laser device located on the lee side of the gas medium flow . 3. A laser medium in a laser tube provided in a waveguide.
Gas is discharged by microwaves introduced into the waveguide.
A microwave-excited gas laser that excites and performs laser oscillation
An electric field generated by the microwave.
Means for controlling the intensity distribution of the laser beam
Means to flow at high speed in the tube, and guide the microwave
The waveguide is a crossed waveguide with crossing points where microwaves cross.
Of a laser tube containing a gas medium to be excited.
The electric field intensity distribution in the radial direction is controlled by electric field intensity distribution control means.
Controlled microwave laser device. Wherein the electric field intensity distribution control means, a microwave excited gas laser apparatus according to any one of claims 1 to 3 is a conductive member. 5. The microwave-excited gas laser device according to claim 4, wherein a plurality of conductive members are provided, and their electric potentials are substantially equal to each other. 6. The electric field intensity distribution control means, a microwave excited gas laser apparatus according to any one of claims 1 to 3 to remove unnecessary electric field in the discharge of the laser tube to be excited gas medium is housed. 7. The microwave-excited gas laser device according to claim 6, wherein the electric field intensity distribution control means is a conductor tube having a shape surrounding the laser tube. 8. The method according to claim 1, wherein the laser medium gas contains CO2 gas.
The microwave-excited gas laser device according to claim 1 .