JP2003264328A - Waveguide gas laser oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waveguide gas laser oscillator which does not use an expensive high frequency power supply which outputs a high frequency of several scores of MHz, and which does not need a heat exchanger for laser gas cooling. <P>SOLUTION: 1. This waveguide gas laser oscillator has a discharge space formed by a pair of discharge electrodes which have ceramics thin films formed on the surface of a conductor and made to be a wave guide space for laser light. The discharge gap of the discharge electrode is 2.5 mm to 10 mm, and the frequency of an alternating current electric field which is impressed on the discharge electrode is 2 MHz or less. 2. As for this waveguide gas laser oscillator, the thickness of the ceramics thin film is 0.01 mm to 0.80 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type gas laser oscillator.

[0002]

2. Description of the Related Art There are the following two basic concepts of the structure of a discharge part in a general waveguide type gas laser oscillator.

1. A high frequency electric field of several tens of MHz or more is applied to the discharge electrode forming the waveguide to narrow the amplitude of electrons and cations drifting in the plasma of the discharge section toward the electrode, and to the electrode surface. It suppresses collisions (called ion traps, ion traps, etc.) and protects the electrode surface, while at the same time reducing input energy loss due to collisions of electrons and cations.

2. The discharge gap of the discharge portion is narrowed to about 1.5 to 2.5 mm, CO ₂ -He the electrode and the laser medium (CO ₂ laser
-N ₂ mixed gas) to increase the thermal coupling (increasing the thermal conductivity,
(There is no temperature distribution between the electrodes) To improve the cooling capacity of the laser gas by the electrodes and eliminate the heat exchanger and blower for cooling the laser gas.

[0005]

[Problems to be Solved by the Invention] In the case described in (1), an expensive high frequency power source having a frequency of several tens of MHz or more is required, and there is also a problem that harmful radio waves leak from the high frequency power source to surrounding electronic devices.

[0006] 2. In the case described in (1), there is a problem that a dielectric protective film such as ceramics for protecting the electrode surface cannot be provided in order to maintain high thermal coupling between the electrode and the laser gas.

The present invention has been made to solve the above problems, and an object of the present invention is to cool a laser gas without using an expensive high frequency power source that outputs a high frequency of several tens of MHz. An object of the present invention is to provide a waveguide type gas laser oscillator that does not require a heat exchanger and a blower.

[0008]

As a means for solving the above-mentioned problems, a waveguide type gas laser oscillator according to claim 1 uses a laser beam for a discharge space formed by a pair of discharge electrodes having a ceramic thin film formed on a conductor surface. In the waveguide type gas laser oscillator having a waveguide space as described above, the discharge gap of the discharge electrode is set to 2.5 mm to 10 mm, and the frequency of the alternating electric field applied to the discharge electrode is set to 2 MHz or less. is there.

A waveguide type gas laser oscillator according to a second aspect is the waveguide type gas laser oscillator according to the first aspect, characterized in that the thickness of the ceramic thin film is 0.01 mm to 0.80 mm. is there.

A waveguide type gas laser oscillator according to a third aspect is the waveguide type gas laser oscillator according to the first aspect, wherein the pair of discharge electrodes are formed in a double cylindrical shape including an outer tube and an inner tube. Is the gist.

A waveguide type gas laser oscillator according to a fourth aspect is the waveguide type gas laser oscillator according to the first aspect, wherein a plurality of units of discharge electrodes, each of which includes the pair of discharge electrodes, are provided. It is what

According to a fifth aspect of the present invention, in the waveguide type gas laser oscillator according to the fourth aspect, the discharge electrodes of the plurality of units are arranged so as to have an L shape or a polygonal shape. It is what

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are explanatory views of a waveguide type gas laser oscillator 1 according to the present invention. As shown in FIGS. 1 and 2, a pair of metal electrodes (6, 7) connected to a high frequency power source 5 for discharge excitation are provided inside the vacuum container 3. The surfaces of the electrodes (6, 7) facing each other are covered with a dielectric thin film 9. The thin film of the dielectric is formed by spraying alumina ceramics or the like on the surface of the metal electrode.

Further, the electrodes (6, 7) are opposed to each other with a discharge gap d, and a discharge space 11 having a rectangular cross section (w × d) is formed between the electrodes (6, 7). The discharge space 11 is filled with a mixed gas of CO ₂ —He—N ₂ which serves as a laser medium.

A flow path (not shown) for cooling the electrode with water is provided inside the electrode (6, 7), and cooling water sent from a cooling device (not shown) is supplied to the electrode (6, 7). It is configured such that it enters from an inflow port 13 provided, flows through an internal flow path, and circulates from the exhaust port 15 to the cooling device. In FIG. 1, a rear mirror (total reflection mirror) 17 and an output mirror 19 for forming an optical resonator are provided in the vacuum vessels 3 on the left and right of the discharge space 11.

Regarding the size of the discharge gap d, for example, in the case of a triaxial orthogonal type carbon dioxide gas laser, the discharge gap is 50 mm, and the discharge voltage needs to be about 5 kV. By setting the range to 10 mm, the discharge voltage can be reduced to about 0.5 kV. That is, the withstand voltage of the thin film 9 made of the dielectric material may be about 0.5 kV.

Therefore, in the embodiment of the present invention, the above-mentioned discharge gap d is set in the range of 2.5 mm to 10 mm, and the thickness of the thin film 9 made of the ceramic dielectric is 0.01 mm to which the withstand voltage is about 0.5 kV. Form in the range of 0.80 mm. Further, since the electrode surface on the side where the discharge is generated is protected from the collision of electrons and ions by the thin film 9 made of the ceramic dielectric, the amplitude of the electrons and cations drifting toward the electrode is increased and the In consideration of the collision phenomenon, the frequency of the alternating electric field applied to the electrodes (6, 7) is set to 2 MHz, which is a relatively low frequency.

In the above structure, 2M is applied to the electrodes (6, 7).
When an AC voltage of Hz is applied, an AC discharge for exciting atoms of the laser medium is generated in the discharge space 11. Laser light is sequentially stimulated and emitted from the atoms excited by the discharge, and the emitted laser light uses the discharge space 11 formed by the discharge electrode as a waveguide space of the laser light to discharge electrodes (6, 7).
The laser light travels in a zigzag manner while being reflected between the output space 11 and is resonance-amplified between a rear mirror 17 and an output mirror 19 that form an optical resonator arranged on the left and right of the discharge space 11, and a part of the amplified laser light is output. It is taken out from 19 as laser light.

Next, another embodiment of the waveguide type gas laser oscillator according to the present invention will be described.

FIG. 3 shows a second embodiment of the waveguide type gas laser oscillator 1 according to the present invention. A waveguide type gas laser oscillator 20 of the second embodiment has a discharge unit of the waveguide type gas laser oscillator 1 Each unit U is formed, and the discharge unit units U ₁ and U ₂ are combined in an L-shape so that almost double output can be obtained. The optical resonator in the waveguide type gas laser oscillator 20 are constituted by eight mirror (M ₁ ~M _8). Incidentally, M ₁ is an output mirror and M ₈ is a rear mirror.

FIG. 4 shows a third embodiment of the waveguide type gas laser oscillator 1 according to the present invention. In the waveguide type gas laser oscillator 30 of the third embodiment, the discharge part of the waveguide type gas laser oscillator 1 is 1 This unit is a unit U, and the discharge unit units U _{1 to} U ₆ are arranged in a regular hexagon, and an output of about 6 times can be obtained. The optical resonator is 24
It is composed of a plurality of mirrors (M _{1 to} M ₂₄ ), where M ₁ is an output mirror and M ₂₄ is a rear mirror.

FIG. 5 shows a fourth embodiment of the waveguide type gas laser oscillator 1 according to the present invention.

Waveguide type gas laser oscillation of the fourth embodiment
The vessel 40 includes six discharge unit units U. ₁~ U₆Release from the center
They are arranged in a radial pattern, and the optical resonator has 24 mirrors.
(M ₁~ M_{twenty four}). In addition, M₁Is output mira
ー 、 M_{twenty four}Is the rear mirror.

The optical path shown in FIG. 5 may be one and a half round trips, two round trips or three round trips in one gap.

FIG. 6 shows a fifth embodiment of the waveguide type gas laser oscillator 1 according to the present invention. A waveguide type gas laser oscillator 50 of the fifth embodiment is a discharge electrode (6, 6) in the waveguide type gas laser oscillator 1. 7) is provided with a cylindrical discharge electrode 55 having a double cylindrical shape composed of an outer tube 51 and an inner tube 53,
The optical resonator is arranged such that the first spherical mirror 57a and the second spherical mirror 57b are opposed to each other with the cylindrical discharge portion of the cylindrical discharge electrode 55 interposed therebetween, and the first spherical mirror 57a and the second spherical mirror 57b are arranged.
The laser light reciprocated a plurality of times between is output from the output mirror 59 provided on the first spherical mirror 57a.

[0027]

According to the invention of claim 1 or 2, since the discharge gap of the discharge electrode is set to a small value of 2.5 mm to 10 mm, the discharge voltage is reduced to about 0.5 kV, and therefore the electrode surface is coated. The withstand voltage of the ceramic dielectric film is also reduced to about 0.5 kV and the thickness of the film is 0.01 mm.
It has become possible to hold in the range of ~ 0.80 mm.

As a result, the cooling efficiency of the laser gas is improved,
The heat exchanger and blower for cooling the laser gas are no longer needed. In addition, since the electrode surface is protected from the collision of electrons and ions with a thin film made of a ceramic dielectric, the phenomenon that the amplitude of electrons and cations drifting toward the electrode becomes large and they collide with the electrode is acceptable, and the frequency is It is possible to use an inexpensive AC power source having a relatively low frequency of 2 MHz.

According to the invention of claim 3, claim 4 or claim 5, in addition to the same effects as those of the invention of claim 1 or claim 2, a large laser output can be obtained and at the same time laser light can be obtained. Isotropic property of is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a waveguide type gas laser oscillator 1 according to the present invention.

FIG. 2 is a sectional view taken along line I-I in FIG.

FIG. 3 is an explanatory view of a second embodiment of the waveguide type gas laser oscillator 1 according to the present invention.

FIG. 4 is an explanatory view of a third embodiment of the waveguide type gas laser oscillator 1 according to the present invention.

FIG. 5 is an explanatory view of a fourth embodiment of the waveguide type gas laser oscillator 1 according to the present invention.

FIG. 6 is an explanatory view of a fifth embodiment of the waveguide type gas laser oscillator 1 according to the present invention.

[Explanation of symbols]

1 Waveguide Gas Laser Oscillator 3 Vacuum Container 5 High Frequency Power Supply 6, 7 Electrode 9 Dielectric Thin Film 11 Discharge Space 13 Cooling Water Inlet 15 Cooling Water Outlet 17 Rear Mirror (Total Reflection Mirror) 19 Output Mirror 19 M ₁ ~ M ₂₄ Mirror U _{1 to} U ₆ Discharge unit w Horizontal length of discharge space d Discharge gap

Claims (5)

[Claims] 1. A waveguide gas laser oscillator having a discharge space formed by a pair of discharge electrodes having a ceramic thin film formed on a conductor surface as a waveguide space for laser light, wherein the discharge gap of the discharge electrodes is 2.5 mm to 10 mm. At the same time, the frequency of the alternating electric field applied to the discharge electrode is set to 2 MHz or less, and a waveguide type gas laser oscillator. 2. The waveguide type gas laser oscillator according to claim 1, wherein the ceramic thin film has a thickness of 0.01 mm to
Waveguide type gas laser oscillator characterized by being 0.80 mm. 3. The waveguide type gas laser oscillator according to claim 1, wherein the pair of discharge electrodes are formed in a double cylindrical shape composed of an outer tube and an inner tube. 4. The waveguide type gas laser oscillator according to claim 1, wherein a plurality of units of discharge electrodes each having the pair of discharge electrodes as one unit are provided. 5. The waveguide type gas laser oscillator according to claim 4, wherein the discharge electrodes of the plurality of units are arranged so as to have an L shape or a polygonal shape.