JP2836517B2 - 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 Various types of so-called microwave-excited gas laser apparatuses have been proposed which perform laser oscillation by discharge-excitation of molecules of a laser medium gas to a high energy state by microwaves.

In such a microwave-excited gas laser device, spatially uniform excitation of the laser medium gas by microwaves is particularly required in terms of oscillation efficiency.

[0004] The non-uniformity of the excitation may cause a streamer discharge which is not suitable for the excitation, may cause partial abnormal heating of the gas, or may cause a spatial non-uniformity of the laser amplification factor. Then, as a result, they cause a decrease in laser oscillation efficiency and a decrease in maximum output.

However, in the case of discharge excitation by 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 space range.
The excitation becomes spatially non-uniform, and it is particularly difficult to make the discharge spatially uniform.

As a countermeasure against this, for example, Japanese Patent Laid-Open No.
According to FIG. 1 or FIG. 2 of JP-A-0975, it is proposed to insert an insulator inside a microwave waveguide to improve the spatial uniformity of the microwave electric field.

However, in this configuration, the uniformity of the electric field intensity distribution is limited to the use of relatively good portions, and an essentially uniform electric field intensity distribution of microwaves is produced. Not something.

[0008]

That is, in the configuration of the conventional microwave-excited gas laser device, an attempt is made to essentially realize a uniform spatial electric field intensity distribution which is difficult because the wavelength of the microwave is short. But nothing was done.

The present invention essentially realizes a microwave-excited gas laser device having a structure capable of uniformizing the intensity distribution of microwaves for discharge excitation, and as a result, a uniform medium can be excited. An object of the present invention is to provide a microwave-excited gas laser device capable of efficiently performing laser oscillation.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a microwave which excites a gas medium to be excited to a high energy state by a microwave oscillated from a microwave oscillator to perform laser oscillation. An excited gas laser device, wherein the excited gas medium is excited by a plurality of microwaves having different electric field oscillation directions.

Further, there is provided a standing wave forming means for converting the microwave into a standing wave, and the gas medium to be excited is connected to each antinode of a plurality of standing wave microwaves having different electric field oscillation directions. It may be a microwave-excited gas laser device that excites the gas medium to be excited at a portion.

It is preferable to excite the gas medium to be excited with a plurality of pulsed microwaves such that the intensity variation of the optical output from the microwave-excited gas laser device becomes a continuous optical output within ± 5%.

In this case, each of the plurality of microwaves is a pulse microwave, and the pulse repetition frequency is 20 kHz.
It is preferable that it is not less than z.

On the other hand, a plurality of pulsed microwaves may each be a pulse group, and the laser output light may be pulsed light.

It is preferable that the plurality of pulsed microwaves excite the gas medium to be excited so as to overlap in time.

Preferably, the duty ratio of the plurality of pulsed microwaves is controlled within 0.1 to 0.3.

Further, when the duty ratios of a plurality of pulsed microwaves are different from each other, it is desirable to synchronize the oscillation start timing.

The electric field vibration directions of the plurality of microwaves may be orthogonal to each other. The gas medium to be excited may be sealed in the laser tube, and at least one of the plurality of microwave electric field vibration directions may intersect the optical axis of the laser tube.

Further, the above-mentioned standing wave forming means is a cavity resonator, and the cavity resonator includes a waveguide having a portion crossing each other, and at the crossing portion, the gas medium to be excited is: The electric field may be excited by a plurality of microwaves having different vibration directions.

Preferably, the waveguide is two waveguides orthogonal to each other. In this case, it is also possible that each of the two waveguides has a microwave oscillator.

[0021] Each of the two waveguides may have a matching device. On the other hand, the configuration may be such that the gas medium to be excited is excited by microwaves oscillated by a single microwave oscillator.

Alternatively, the standing wave forming means is a cavity resonator, and the cavity resonator includes a waveguide having a portion crossing each other, and at the crossing portion, the gas medium to be excited is:
The electric field may be excited by a plurality of microwaves having different vibration directions.

In this case, a plurality of microwaves may be obtained by splitting a microwave oscillated by a single microwave oscillator.

Then, the microwave oscillated from the microwave oscillator propagates through a single waveguide, is branched into a plurality of microwaves by a microwave distributor, and crosses the waveguides by the plurality of waveguides. May be guided to the excited gas medium located in the section.

This waveguide has a matching device, and the position of the waveguide is between the microwave oscillator and the microwave distributor or at the intersection of the microwave distributor and the waveguide. It may exist in between.

On the other hand, a plurality of microwaves propagate microwaves oscillated by a single microwave oscillator in a return pattern,
A configuration obtained by passing the excited gas medium a plurality of times may be used.

[0027] The waveguide may have a matching device, and the position of the waveguide may be present between the microwave oscillator and the microwave distributor.

The standing wave forming means is a cavity resonator,
The cavity resonator may be a rectangular parallelepiped cavity resonator.

This rectangular parallelepiped cavity resonator may have a microwave oscillator on each of two surfaces sharing one side of the rectangular parallelepiped.

Further, the rectangular parallelepiped cavity resonator may have matching devices on two surfaces sharing one side.

On the other hand, the standing wave forming means may be a cavity resonator, and the cavity resonator may be a cylindrical cavity resonator.

This cylindrical cavity resonator may have two microwave oscillators. The cylindrical cavity resonator may further include a matching device.

The gas medium to be excited is sealed in a laser tube, and the two microwave oscillators have an antenna unit for oscillating microwaves, and the antenna unit projects in the optical axis direction of the laser tube. In this case, they may extend in directions orthogonal to each other.

The frequency of the plurality of microwaves is 0.1
They may be different from each other within GHz.

The plurality of microwaves may be two microwaves, each having the same frequency, and different in time phase difference between the microwaves within 90 degrees ± 4.5 degrees.

This time phase difference is equal to (１ ／ + の) of the wavelengths of a plurality of microwaves in which the difference in the propagation distance between two microwaves from the microwave oscillator to the gas medium to be excited is equal to each other.
N / 2) times (N is an integer of 0 or more).

The difference in propagation distance between the two microwaves from the microwave oscillator to the gas medium to be excited is within an error range of ± 5%.

On the other hand, the time phase difference may be obtained by inserting a phase shifter into at least one of the two microwave propagation paths.

Further, a standing wave adjusting means for adjusting a standing wave state of the microwave may be further provided. Specifically, the standing wave adjusting means is preferably a short plunger having a porosity.

The microwave frequency is 2.45 GHz.
z ± 0.05 GHz is preferred.

[0041]

[Function] With the above configuration, the excitation is made two-dimensionally uniform.
The homogenization results in a spatially uniform excitation.

[0042]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. This embodiment relates to a microwave-excited gas laser device having a cavity constituted by two intersecting waveguides.

FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along a plane including the x-axis and the y-axis when the microwave pulse in FIG. 1 is ON.

1 and 2, reference numeral 10 denotes a cavity resonator;
11 and 12 are microwave oscillators, 13 and 14 are waveguides,
15 is a laser tube, 16 is an output mirror, 17 is a total reflection mirror, 18
To 21 are plungers, and 22 and 23 are matching devices having a structure having three stub tuners.

Further, 24 and 25 are microwave oscillators 1
Reference numerals 1 and 12 denote antennas, 26 denotes an electric field intensity distribution of microwaves generated by the microwave oscillator 11 in the y direction, 27 denotes an electric field intensity distribution of microwaves generated by the microwave oscillator 12 in the x direction, and 29 denotes a laser medium gas. is there.

Next, FIGS. 3A to 3C are enlarged sectional views showing a discharge state inside the laser tube 15 of FIG.

FIG. 3A shows a discharge state when only the y-direction electric field is applied, and FIGS. 3B and 3C show a discharge state when the y-direction electric field and the x-direction electric field are applied simultaneously. 3
FIG. 3B shows the moment when the electric field is directed in the y direction.
(C) shows the moment when the electric field is directed in the x direction.

In FIG. 3, reference numerals 30 and 31 denote y-direction electric flux lines, 32 denotes an x-direction electric flux line, and 33 and 34 denote discharge regions in a discharged state.

In the microwave-excited gas laser apparatus configured as described above, in particular, CO
_The following operation will be described assuming a _two- 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, the present invention can be applied to a CO gas laser, a N ₂ gas laser, a metal vapor laser, a rare gas laser, a He—Ne laser, an ion laser and the like.

First, as shown in FIGS. 1 and 2, microwaves (oscillation frequencies of 2.45 GHz ± 0.05 GHz, respectively) generated from microwave oscillators 11 and 12 propagate through waveguides 13 and 14. , Are matched by matching units 22 and 23.

Here, the waveguides 13 and 14 intersect each other at the position of the laser tube 15, but are orthogonal to each other in the present embodiment.

In this embodiment, the laser tube 1
At the position 5, the microwaves from the microwave oscillator 11 and the microwave oscillator 12 have the electric field directions orthogonal to each other.

Therefore, the two microwave oscillators 11, 1
Microwaves oscillated from 2 have traveling directions orthogonal to each other, and their electric field oscillation directions (directions of electric field vectors) are also orthogonal to each other.

By the two orthogonal microwave electric fields, the laser medium gas 29 (the mixed gas of CO ₂ , N ₂ , and He at a ratio of 1: 9: 40 in the laser tube 15 has a pressure of 6)
(Approximately 0 Torr) by discharge excitation, and laser light is output in the z-axis direction from an optical resonator constituted by the total reflection mirror 17 and the output mirror 16.

Here, regarding the microwave, y in FIG.
As shown by the directional electric field distribution 26 and the x-directional electric field distribution 27,
The plungers 18, 19, 20, and 21 are moved and adjusted so that the laser tube 15 is positioned at the antinode of the standing wave.

This is because the electric field intensity required for starting discharge is about 1 kV / cm, but in the case of a traveling wave of a microwave of 1 kW, the electric field intensity is at most about 500 V / cm.
cm, which is insufficient for starting 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 portion of the laser tube 15, so that the discharge can be easily started.

The matching devices 22 and 23 adjust the microwave oscillators 11 and 12 and the discharge load so as to be in an optimum matching state.

Although not explicitly shown in FIG. 1, if necessary, a gas cooling and circulating mechanism can be provided in which the laser medium gas 29 is drawn out of the laser tube 15 by a pipe and, after cooling, is again injected by a pump. .

Hereinafter, the discharge state of the microwave in this embodiment will be described in detail.

FIG. 3A shows a discharge state when only a y-direction electric field is applied, and shows a state where an electric field is applied in one direction.

That is, in FIG. 2, only the microwave oscillator 11 is oscillated, and only the electric field in the y direction is applied to the laser tube 15.

The electric field distribution 26 in the y direction is strong at the center of the laser tube 15 corresponding to the wavelength of the microwave, and weak at the left and right ends.

Therefore, as shown in FIG. 3 (a), the discharge 33 discharges vertically and thinly at the central portion, and uniform excitation of the laser medium gas cannot be achieved.

However, also in this case, the discharge state is uniform in the vertical direction (y direction) in the vertically long figure.

The reason for this is that since the electric flux line 30 is continuous in the y-direction, the change in the electric field strength in the y-direction is considered to be small.

On the other hand, in the horizontal direction (x direction) in the figure, the electric field intensity greatly changes in the x direction because the density of the electric flux lines greatly changes in the x direction.

FIGS. 3B and 3C show discharge states at the moment when the combined electric field when the y-direction electric field and the x-direction electric field are applied simultaneously is directed in the y-direction and the x-direction, respectively.

That is, FIG. 2 shows a state in which the microwave oscillators 11 and 12 oscillate simultaneously and an electric field in the x direction and an electric field in the y direction are simultaneously applied to the laser tube 15.

Since the microwave oscillators 11 and 12 are separate microwave oscillators, even if they oscillate at 2.45 GHz, they do not oscillate exactly at the same frequency, and there is a difference in oscillation frequency of several MHz or more.

As described above, when the vibration frequencies of the two electric fields are different, the phase difference δ changes with time.

At this time, the trajectory drawn by the composite vector repeats a circle-ellipse-straight line-ellipse-circle as δ changes.

This repetition frequency corresponds to the difference frequency between two different oscillation frequencies. Specifically, the combined electric field is the frequency of the corresponding microwave (2.4 in this embodiment).
From 2.5 GHz to 2.5 GHz), and
This rotation changes the state at a difference frequency between the two different frequencies (0.1 GHz at the maximum in this embodiment).

Therefore, the moment when the combined electric field is directed in the y direction is as shown in FIG. 3B, and the moment when the combined electric field is directed in the x direction is as shown in FIG. 3C.

At the moment when the combined electric field is directed in the y direction, the discharge is made uniform in the y direction as described above, and when the combined electric field is turned in the x direction, the discharge is made uniform in the x direction. .

Furthermore, in practice, the direction of the combined electric field extends in all directions in the two-dimensional space corresponding to the difference frequency of the oscillation frequency, so that the discharge region spreads two-dimensionally as a whole, and FIG. As shown in (c), a uniform discharge region having a substantially circular cross section is realized.

In the present embodiment, the microwaves oscillated from the microwave oscillators 11 and 12 may have any other form, but pulse microwaves may be used.

These two pulsed microwaves are applied substantially simultaneously at the position of the laser tube 15.

FIG. 4 shows the case where the laser beam was observed at the position of the laser tube.
1 shows a schematic diagram of one pulsed microwave.

The important point here is the ON / OFF of the two pulses.
That is, the OFF timings coincide.

That is, in order to realize the above-mentioned uniform discharge, two pulsed microwaves need to overlap in time regardless of whether the laser output light is continuous light or pulsed light.

This is because when the timings are shifted from each other, for example, when the microwave oscillator 12 is turned off first, the discharge state instantaneously becomes the state shown in FIG. This is because the effect of three different electric field intersections cannot be achieved.

Since the excited state of CO2 molecules contributing to laser oscillation is said to be almost completely lost in about 200 μs, it is necessary to take out the laser light output in a continuous state.
At least (1/200 μs) Hz, ie 5 kHz
About a repetition frequency is required.

However, if the frequency is 5 kHz as it is, the output will have an intensity fluctuation rate of 100%. Therefore, in order to realize an intensity fluctuation within ± 5% in which the laser beam can be regarded as continuous, a repetition frequency of about 20 kHz is required. At a minimum, it will be considered necessary.

In summary, in this embodiment, the excitation is made extremely uniform by creating the above-described simultaneous application state of the x-direction electric field and the y-direction electric field.

Specifically, in the discharge in the unidirectional electric field application state shown in FIG.
% And the laser output was about 70 W, but in the configuration shown in FIGS. 3B and 3C of this embodiment, the discharge area was 80% or more of the sectional area of the laser tube 15. A discharge region is realized, and the laser output also achieves 180 W or more.

In this embodiment, the number of microwave oscillators and the number of waveguides has been described as two. However, three or more microwave oscillators and waveguides can be provided if necessary.

The direction of the microwave electric field vibration does not necessarily have to be completely orthogonal as long as it intersects at least with the optical axis of the laser tube, and the relative directions of the vibrations also intersect at least. If they do, they need not necessarily be completely orthogonal.

Further, in this embodiment, the antinode position of the standing wave of the microwave can be adjusted by moving the plunger in the x direction or the y direction.

The plunger is typically in the form of a flat plate. However, a plurality of holes may be provided so that microwaves cannot escape to the outside so that the inside can be observed.

This plunger is the same in Embodiments 2 and 3 described below.

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

This embodiment relates to a microwave-excited gas laser as in the first embodiment.
Using one microwave oscillator without using this, as a result,
An example of a configuration in which an electric field achieves application of microwaves orthogonal to each other from two directions is shown.

FIG. 5 is a sectional view showing a second embodiment of the present invention, and corresponds to FIG. 2 of the first embodiment.

In FIG. 5, parts corresponding to those in FIG. 2 are given the same numbers, but 105 is a cavity resonator, 41 is one microwave oscillator, 42, 43 and 44 are waveguides,
The waveguides 43 and 44 are orthogonal to each other at the position of the laser tube 15.

Here, the matching devices 22 and 23 are attached to the waveguides 43 and 44, respectively, but the waveguide 42 may have a matching device.

Reference numeral 46 denotes a microwave distributor, and the microwave propagating through the waveguide 42 is supplied to the microwave distributor 46.
, And each microwave propagates through the waveguide 43 and the waveguide 44, respectively.

The device of the present embodiment having the above-described structure is different from the device of the first embodiment in that the components from the microwave oscillator 41 to immediately before the matching devices 22 and 23 of the waveguides 43 and 44 are different. Only the difference is that the configuration near the laser tube 15 is exactly the same.

The two microwaves distributed by the microwave distributor 46 intersect each other at the position of the laser tube 15, and form a microwave electric field in two directions in which the vibration direction of the electric field is spatially orthogonal to the laser tube 15. Applied.

However, unlike the first embodiment, since the frequencies of the microwaves in the two directions are completely the same, no difference frequency is generated. In general, the direction of the electric field in the laser tube 15 is x-axis direction, It does not face uniformly in all directions of the 360-degree space including the y-axis direction.

More specifically, when the temporal phase difference between the microwaves in the two directions is 0 degree or 180 degrees, only a linear polarization state is obtained in which the microwaves are oriented in a spatial direction obliquely 45 degrees from the x-axis or the y-axis. is there.

Also, the time phase of the microwave in two directions is 9
When the angle is different by 0 degrees, a circular polarization state is established, and the light is instantaneously directed in all directions in a 360-degree space including the x-axis direction and the y-axis direction.

When the phase difference is a halfway angle other than the above, the state becomes an elliptical polarization state, the directions are not uniformly oriented in all directions, the specific directions become strong, and the discharge state is not uniform. .

Therefore, in the present embodiment, in order to actually realize a state in which the temporal phases of the microwaves in the two directions differ by 90 degrees, as shown in FIG. The difference (lb-la) between the distance l a passing through the waveguide 43 and the distance l b passing through the waveguide 44 is set to １ ／ of the wavelength of the microwave in the waveguide.

Note that this difference in distance is generally (（)
+ N / 2) wavelength (N is an integer of 0 or more).

Even when the distance la (the distance passing through the waveguide 43) and the distance lb (the distance passing through the waveguide 44) are the same, at least one of the waveguides 43 and 44 has a laser tube. By inserting a phase shifter such that the temporal phase difference at 15 becomes 90 degrees, the same effect as that of producing the temporal phase difference by the above distance difference can be obtained.

The phase shifter can be formed of a material having a dielectric constant different from that of a usual substance in a waveguide.

With the above configuration, the direction of the microwave electric field in the laser tube 15 instantaneously goes in all directions in the space.

Further, in the first embodiment, it is impossible to realize only a perfect circular polarization state, and it is inevitable to include an elliptical polarization state and a linear polarization state. Only a circularly polarized state can be realized.

It is ideally desirable that the temporal phase of the two microwave electric fields be exactly 90 degrees (complete circular polarization state), but some degree of elliptical polarization is acceptable. The allowable range was evaluated as ± 4.5 degrees.

This ± 4.5 degrees is ± 5 degrees in percentage notation.
%, The permissible error range of the distance difference (lb-la) is ± 5%.

Therefore, in the present embodiment, it is possible to achieve the same or a more uniform excitation state as in the first embodiment with one microwave oscillator.

In the present embodiment, the case where the number of branches of the waveguide is two has been described as a representative, but it is also possible to branch three or more as necessary.

The direction of the electric field oscillation of the microwave does not necessarily have to be completely orthogonal as long as it intersects at least the optical axis of the laser tube.

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

The embodiment of the present invention relates to a microwave-excited gas laser as in the first embodiment. As in the second embodiment, two microwave oscillators are not used and one microwave oscillator is used. This is an embodiment for realizing application of microwave electric fields in two directions where electric fields are spatially orthogonal to each other.

FIG. 6 is a sectional view showing a third embodiment of the present invention, and corresponds to FIG. 2 of the first embodiment.

In FIG. 6, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, 106 is a cavity resonator, 61 is a microwave oscillator, 62 is a matching box, 63 is a waveguide, and 64 and 65 are It is a plunger.

The waveguide 63 is configured such that a single waveguide is bent to form an overlapping portion, and the laser tube 15 is positioned at the overlapping portion. They are orthogonal to each other at the position of the tube 15.

Although the matching device 62 is provided between the microwave oscillator 61 of the waveguide 63 and the laser tube 15, the matching device may be provided in other portions of the waveguide 63.

The device according to the third embodiment having the above-described configuration uses a single microwave oscillator.
This embodiment is the same as that of the first embodiment, except that this embodiment does not require a microwave distributor.

In this embodiment, the microwave oscillator 6
Microwave oscillated from 1 is bent waveguide 6
3 intersect each other at the overlapping portion, that is, the position of the laser tube 15, and the electric field is applied to the laser tube 15 as a microwave electric field in two directions orthogonal to each other in space.

Also in this embodiment, as in the second embodiment, the microwave frequencies in the two directions are exactly the same, so that the electric field direction in the laser tube 15 is generally It does not lead to all directions of the 360-degree space including the y-axis direction.

Therefore, as shown in FIG.
The distance lc from the center point C to the center point C around the waveguide 63 and returning to the center point C is set to 1/4 wavelength of the wavelength in the waveguide of the microwave. Achievable can be achieved.

The distance lc is generally (1/4 + N
/ 2) wavelength (N is an integer of 0 or more).

Further, even when the distance lc is not equal to the (1/4 + N / 2) wavelength, a predetermined phase shifter such that the temporal phase difference in the laser tube 15 becomes 90 degrees is inserted in the middle. If so, a similar effect can be obtained.

The number of times the waveguide 63 is circulated is not limited to two, but may be any number as long as the above conditions are satisfied.

With the above configuration, in this embodiment,
Since the direction of the electric field of the microwave in the laser tube 15 is instantaneously directed in all directions in the space, uniform excitation can be achieved as in the first and second embodiments.

In the present embodiment, in addition to being able to be configured with one microwave oscillator, a simple configuration requiring only one matching device can be realized.

In this embodiment, the intersection of the waveguides is 2
The explanation was made on behalf of a multiple crossing, but if necessary, 3
It is possible to cross more than once.

The direction of microwave electric field oscillation does not have to be completely orthogonal as long as it intersects at least the optical axis of the laser tube.

Embodiment 4 Hereinafter, a fourth embodiment of the present invention will be described in detail with reference to the drawings.

FIGS. 7A and 7B are cross-sectional views of two modes showing a fourth embodiment of the present invention, each corresponding to FIG. 2 of the first embodiment.

FIG. 7A shows a microwave-excited gas laser device composed of a rectangular parallelepiped cavity resonator composed of a rectangular parallelepiped. FIG. 7B shows a cylindrical cavity resonator composed of a cylindrical body.

In FIG. 7, parts corresponding to those in FIG. 2 are given the same numbers, but 107 is a rectangular parallelepiped cavity resonator,
Reference numeral 8 denotes a cylindrical cavity resonator; 71, 72, 81, and 82 are microwave oscillators; 73, 74, 83, and 84 are microwave oscillator antennas; and 75, 76, 85, and 86 are matching devices.

In these embodiments, in order for the directions of vibration of the electric fields of two different microwaves to be orthogonal to each other, it is necessary to use antennas 73 and 74 or 83 and 84 of the microwave oscillator.
Need to extend perpendicular to each other when both antennas are projected in the direction of the laser optical axis (the direction perpendicular to the plane of the drawing).

The configuration shown in FIG. 7A of the fourth embodiment configured as described above has a configuration in which the waveguide portion of the configuration of the first embodiment is cut short. FIG. 7 (b)
In the configuration shown in FIG. 7A, the cavity resonator shown in FIG. 7A is formed in a cylindrical shape. Therefore, two microwave oscillators are used, and the oscillation frequency of the microwaves oscillated by these two microwave oscillators is This is similar in that they are different from each other and that two matching devices are used.

Therefore, the operation principle is the same as that of the first embodiment, and a uniform discharge is realized by directing the direction of the electric field in all the 360-degree spaces at the difference frequency between the two microwaves.

As compared with the apparatus of the first embodiment,
The waveguide portion extending in the x-axis direction and the y-axis direction in FIG. 2 is not used in the present embodiment, and the cavity resonator is downsized. Further, in the first embodiment, there is no plunger having a total of four plungers in the present embodiment, and the simplification of the attached device is achieved.

The adjustment of the waveform of the standing wave and the antinode position is possible on the paper of FIG. 7A constituting the rectangular parallelepiped cavity resonator.

In the case of the cylindrical cavity resonator shown in FIG. 7B, the same adjustment can be made. That is, in the present embodiment, the configuration of the first to third embodiments is further advanced, and the miniaturization of the cavity resonator and the simplification of the attachment device are realized.

In the present embodiment, the description has been made by exemplifying the case where the number of the microwave oscillators is two.
It is also possible to provide three or more.

The direction of the microwave electric field vibration does not necessarily have to be completely orthogonal as long as it intersects the optical axis of the laser tube at least, and the relative directions of the vibrations also intersect at least. If they do, they need not necessarily be completely orthogonal.

(Embodiment 5) Hereinafter, a fifth embodiment of the present invention will be described in detail with reference to the drawings.

An apparatus having the same configuration as that of the first embodiment was used. In the present embodiment, the microwaves oscillated from the microwave oscillators 11 and 12 are pulse microwaves, although those having other forms can be used.

The two pulsed microwaves are applied substantially simultaneously at the position of the laser tube 15.

FIG. 4 shows the case where the laser beam was observed at the position of the laser tube.
1 shows a schematic diagram of one pulsed microwave.

There are two important points here. The first point is to optimize the duty of the pulse microwave according to the flow rate of the laser medium gas 29 flowing in the laser tube 15.

This is because if the duty is too large with respect to the flow rate of the laser medium gas 29, the laser medium gas 29
This causes abnormal heating of the semiconductor laser and makes it impossible to obtain a stable discharge, resulting in a decrease in laser output.

The second point is that the timings of the two pulses coincide as described in the first embodiment.

That is, in order to realize the above-mentioned uniform discharge, two pulsed microwaves need to overlap in time regardless of whether the laser output light is continuous light or pulsed light.

This is because when the timings are shifted from each other, for example, when the microwave oscillator 12 is turned off first, the discharge state is instantaneously changed to the state shown in FIG. This is because the effect of three different electric field intersections cannot be achieved.

Therefore, in this embodiment, the power sources of the microwave oscillators 11 and 12, which are the microwave generation sources, are used as shown in FIG.
The following was used.

In FIG. 8, reference numeral 91 denotes a pulse generation circuit;
2 is a pulse delay circuit, 93 is a high voltage power supply (y) for driving the micro oscillator 11, and 94 is a high voltage power supply (x) for driving the micro oscillator 12.

In FIG. 8, a pulse signal set to an arbitrary frequency by a pulse generating circuit 91 is branched by a pulse delay circuit 92 into a plurality of pulse signals. The duty ratio and the mutual delay of the pulse signal branched by the pal delay circuit 92 can be arbitrarily set.

The branched pulse signal is applied to microwave oscillators 11 and 12 via a high voltage power supply (y) 93 and a high voltage power supply (x) 94 to generate a pulsed microwave.

An example of laser oscillation when the duty of the pulse microwave oscillated from the microwave oscillators 11 and 12 is varied by the pulse generation circuit 91 and the pulse delay circuit 92 in FIG. 8 will be described.

Here, the duty is defined as the ratio between the average power applied to the microwave oscillators 11 and 12 and the peak current.

As shown in FIG. 9, when the duty is increased, the oscillation efficiency is gradually increased, and the duty is increased by 0.2.
It was found that a maximum oscillation efficiency of 18.1% was obtained in the vicinity, and that the oscillation efficiency tended to gradually decrease as the duty was increased.

Since the oscillation efficiency of a microwave-excited gas laser that can be used practically without hindrance is considered to be within a range of ± 2% of the maximum oscillation efficiency, a duty range of about 0.1 to 0.3 is practically used. If it is within the range, even if the duty is deviated, it can be provided to a sufficient practical use.

Next, pulse signals having different duties are applied to the microwave oscillators 11 and 12, respectively.
Laser oscillation was performed by shifting the timing of the pulse microwave in the x direction with reference to the pulse microwave in the y direction.

The pulse frequency from the pulse generation circuit 91 is 25 kHz, and the duty ratio of the pulse signal applied in the y direction by the pulse delay circuit 92 is 20.0%.
(Pulse width: 8 μs), the duty ratio of the pulse signal applied in the x direction is set to 15.0% (pulse width: 6 μs), and the timing of the pulse microwave in the x direction is determined with reference to the pulse microwave in the y direction. 1μs within ± 5μs
Laser oscillation was carried out by shifting each time. The microwave input power is 956W. For example, as shown in FIG.
When the timing in the x direction is advanced by t = 5 μs with respect to the y direction, the laser output is 131 W (the oscillation efficiency is 13.7).
%), And when there is no timing shift between the y direction and the x direction, the laser maximum output is 156 W (the oscillation efficiency is 16.16%).
3%). When the timing in the x direction is delayed by t = 5 μs with respect to the y direction, the laser output becomes 1
20 W (12.5% of oscillation efficiency).

FIG. 10 shows the result of shifting the timing shift time in the x direction by 1 μs with respect to the y direction in this way.

As shown in FIG. 10, the laser output gradually decreases with the shift time, and when the shift exceeds 5 μs, the laser output extremely decreases.

Further, when the deviation time is about 2 μs, the form of the plasma changes, and uniform excitation cannot be expected.
It is necessary to keep the deviation within a range of at least ± 1 μs.

As described above, when the duties are shifted from each other, uniform excitation can be performed by adjusting the oscillation start timing within the range of ± 1 μs, and a high output can be obtained.

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 of the above embodiments, the matching device is 2
It may take any form of a stub tuner, a three stub tuner, or an EH tuner.

In all of the above embodiments, it is preferable that the cavity is 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 glass, 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 medium to be excited can include 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 medium to be excited can be circulated by a gas circulator system including a laser tube, a gas circulation pump, a heat exchanger, and gas piping.

[0177]

As described above, according to the present invention, the vibration direction of the electric field is spatially orthogonal to the same portion of the medium to be excited at the same time.
The configuration that applies a microwave electric field in
It is possible to achieve uniform spatial and uniform excitation by spatially uniformizing / homogenizing.

As a result, a microwave-excited gas laser device that can excite a uniform medium can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of the first embodiment.

FIG. 3 is an enlarged sectional view showing a discharge state inside the discharge tube of the first embodiment.

FIG. 4 is a diagram showing the electric field strength of the microwave of the first embodiment.

FIG. 5 is a sectional view of the second embodiment.

FIG. 6 is a sectional view of the third embodiment.

FIG. 7 is a sectional view of the fourth embodiment.

FIG. 8 is a block diagram of a control circuit for driving the microwave oscillator according to the fifth embodiment.

FIG. 9 is an explanatory diagram showing laser oscillation characteristics when the duty ratio of the fifth embodiment is varied.

FIG. 10 is an explanatory diagram showing laser oscillation characteristics when the timing when the duty of the pulse microwave applied in the y and x directions is different in the fifth embodiment is varied.

[Explanation of symbols]

 Reference Signs List 10 cavity resonator 11 microwave oscillator 12 microwave oscillator 13 waveguide 14 waveguide 15 laser tube 16 output mirror 17 total reflection mirror 18 plunger 19 plunger 20 plunger 21 plunger 22 matching device 23 matching device 24 antenna 25 antenna 26 Electric field distribution in the y direction 27 Electric field distribution in the x direction 29 Laser medium gas 30 Electric line in the y direction 31 Electric line in the y direction 32 Electric line in the x direction 33 Discharge 34 Discharge 42 Waveguide 43 Waveguide 44 Waveguide 45 Plunger 46 Microwave distributor 61 Microwave oscillator 62 Matching device 63 Waveguide 64 Plunger 65 Plunger 71 Microwave oscillator 72 Microwave oscillator 73 Antenna 74 Antenna 75 Matching device 76 Matching device 81 Microwave oscillator 82 Microwave oscillator 83 Antenna 84 Antenna 8 5 Matching Device 86 Matching Device 91 Pulse Generation Circuit 92 Pulse Delay Circuit 93 High Voltage Power Supply (y) 94 High Voltage Power Supply (x) 105 Cavity Resonator 106 Cavity Resonator 107 Cavity Resonator 108 Cavity Resonator

Continuation of the front page (72) Inventor Koichi Sato 3-10-1, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Minoru Kimura 3-10, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture No. 1 Matsushita Giken Co., Ltd. (56) References JP-A-2-78285 (JP, A) JP-A-3-125485 (JP, A) JP-A-5-251803 (JP, A) JP-A-50- 54172 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01S 3/097-3/0979

Claims (35)

(57) [Claims] An apparatus for generating a plurality of microwaves having different vibration directions of an electric field from an excited gas medium and an electric field.
Before using the microwave generator, a microwave generated by said microwave generator
Gas exciting means for exciting the gas medium to be excited
A microwave-excited gas laser device , wherein the gas-exciting means intersects the plurality of microwaves and
At the same part of the excitation gas medium,
Microwave-excited gas laser device for applying the electric field of waves
Place . 2. The apparatus according to claim 1, further comprising a standing wave forming means for converting the microwave into a standing wave, wherein the gas medium to be excited is connected to each antinode of a plurality of standing wave microwaves having different electric field vibration directions. 2. The microwave-excited gas laser device according to claim 1, wherein the excited gas medium is excited at a portion. 3. The microwave-excited gas laser device according to claim 2, wherein the microwave-excited gas laser device is excited by a plurality of pulsed microwaves such that the intensity fluctuation of the light output from the microwave-excited gas laser device becomes a continuous light output within ± 5%. 4. The microwave-excited gas laser device according to claim 3, wherein each of the plurality of microwaves is a pulsed microwave, and the pulse repetition frequency is 20 kHz or more. 5. The microwave excited gas laser device according to claim 2, wherein the plurality of pulsed microwaves are each a pulse group, and the laser output light is pulsed light. 6. plurality of pulsed microwave, a microwave excited gas laser apparatus according to any preceding claim, 3 where the duty ratio is characterized in that it is controlled to within 0.1 to 0.3. 7. A plurality of pulsed microwave microwave excitation gas laser device according to any one of claims 3 to 6 when the duty ratio is different from each other is that characterized by timing the start of oscillation. 8. A plurality of microwave microwave excitation gas laser device according to any one of claims 2 to 7, the electric field vibration directions are orthogonal to each other. 9. A gas medium to be excited is sealed in a laser tube, and at least one of a plurality of microwave electric field oscillation directions.
9. The microwave-excited gas laser device according to claim 8, wherein two electric-field oscillation directions intersect the optical axis of the laser tube. 10. The standing wave forming means is a cavity resonator,
The cavity resonator includes a waveguide having a portion intersecting each other, at a portion where the intersecting, the excitation gas medium, claims 2 vibration direction of the electric field is excited by a plurality of microwaves different 9 A microwave-excited gas laser device according to claim 1. 11. The microwave-excited gas laser device according to claim 10 , wherein the waveguides are two waveguides orthogonal to each other. 12. The microwave-excited gas laser device according to claim 11 , wherein each of the two waveguides has a microwave oscillator. 13. The microwave-excited gas laser device according to claim 12 , wherein each of the two waveguides has a matching device. 14. the excitation gas medium, according to claim 2 in which a single microwave oscillator is excited by the microwaves oscillated
10. The microwave-excited gas laser device according to any one of items 1 to 9 . 15. The standing wave forming means is a cavity resonator,
15. The cavity resonator according to claim 14 , wherein the cavity resonator includes a waveguide having portions that intersect each other, and at the intersections, the gas medium to be excited is excited by a plurality of microwaves having different vibration directions of an electric field. Microwave-excited gas laser device. 16. The microwave-excited gas laser device according to claim 15 , wherein the plurality of microwaves are obtained by branching a microwave oscillated by a single microwave oscillator. 17. A microwave oscillated from a microwave oscillator propagates through a single waveguide, is branched into a plurality of microwaves by a microwave distributor, and crosses the waveguides by the plurality of waveguides. Claims: Guided to the excited gas medium located in the part
17. The microwave-excited gas laser device according to item 16 . 18. plurality of microwaves, to propagate microwaves single microwave oscillator oscillates in Kaejo microwave according to claim 15, obtained by multiple passes through the excitation gas medium Excitation gas laser device. 19. The standing wave forming means is a cavity resonator,
3. The cavity resonator according to claim 2 , wherein the cavity resonator is a rectangular cavity resonator.
10. The microwave-excited gas laser device according to items 9 to 9 . 20. The microwave-excited gas laser device according to claim 19 , wherein the rectangular cavity resonator has a microwave oscillator on each of two surfaces sharing one side of the rectangular parallelepiped. 21. The microwave-excited gas laser device according to claim 20, wherein the rectangular parallelepiped cavity has a matching device on each of two surfaces sharing one side. 22. The standing wave forming means is a cavity resonator,
3. The cavity resonator according to claim 2 , wherein the cavity resonator is a cylindrical cavity resonator.
10. The microwave-excited gas laser device according to items 9 to 9 . 23. The microwave-excited gas laser device according to claim 22 , wherein the cylindrical cavity resonator has two microwave oscillators. 24. A gas medium to be excited is sealed in a laser tube, and the two microwave oscillators have an antenna unit for oscillating microwaves, and the antenna unit projects in an optical axis direction of the laser tube. The microwave-excited gas laser device according to any one of claims 20 , 21 , and 23 , wherein the microwave-excited gas laser device extends in a direction orthogonal to each other. 25. The frequency of the plurality of microwaves, a microwave excited gas laser apparatus according to any of different claims 1 to each other 13, or 19 to 24. 26. The difference between the frequencies of the plurality of microwaves is
26. The microwave-excited gas laser device according to claim 25, which is within 0.1 GHz. 27. plurality of microwave is two microwave, equal each frequency, and claims 14 to time-phase difference of mutual microwave are different within 90 ° ± 4.5 ° 18 The microwave-excited gas laser device according to any one of the above. 28. The time phase difference is (１ ／ + の) of the wavelengths of a plurality of microwaves in which the difference in propagation distance between two microwave oscillators from the microwave oscillator to the gas medium to be excited is equal to each other.
28. The microwave-excited gas laser device according to claim 27 , wherein the microwave-excited gas laser device is obtained by setting it to be (N / 2) times (N is an integer of 0 or more). 29. A difference in propagation distance between two microwaves from a microwave oscillator to a gas medium to be excited is a distance difference of ± 5.
29. The microwave-excited gas laser device according to claim 28 , which is within the range of%. 30. The microwave excited gas laser device according to claim 27 , wherein the time phase difference is obtained by inserting a phase shifter into at least one of two microwave propagation paths. 31. Furthermore, the microwave excitation gas laser device according to any one of claims 2 having a standing wave adjusting means for adjusting the state of the standing microwave 30. 32. The microwave excited gas laser device according to claim 31 , wherein the standing wave adjusting means is a short plunger having a porosity. 33. The electric field oscillation directions of a plurality of microwaves are mutually different.
2. The microwave-excited gas laser according to claim 1, wherein
Equipment . 34. A gas medium to be excited is sealed in a laser tube.
And at least one of a plurality of microwave electric field oscillation directions.
Two electric field oscillation directions intersect the optical axis of the laser tube
Item 34. The microwave-excited gas laser device according to item 33 . 35. The gas medium to be excited is a single microwave.
An oscillator is excited by the oscillated microwave.
A microwave-excited gas laser device according to claim 1 .