JPH05110177A - Laser oscillation device - Google Patents

Abstract

PURPOSE:To enable a laser oscillation device to achieve a high efficiency and a large output. CONSTITUTION:A microwave generator 9 and a plurality of hollow resonators 1A and 1B which are connected through a microwave distributor 12 are provided. Then, a plurality of discharge tubes 2A and 2B which are placed in sequence in series, an total-reflection mirror 3 for light resonance for resonating laser beam within the discharge tube which is provided at final and front edge parts of the discharge tube, a partial penetration mirror 4, a blower 8 which supplies a laser medium gas to the discharge tubes 2A and 2B in circulation, and a heat exchanger 7A for cooling which is provided at a laser medium gas flow-out edge part of the discharge tube are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillating device utilizing discharge excited by electromagnetic waves in the microwave range.

[0002]

2. Description of the Related Art A conventional laser oscillating device using microwaves will be outlined with reference to FIG.

In FIG. 6, reference numeral 1 is a cavity resonator, and 2 is a discharge tube made of a dielectric material such as a glass tube penetrating the cavity resonator and housed inside the cavity resonator. At both ends, a total reflection mirror 3 and a partial transmission mirror 4 are provided facing each other to form an optical resonator. In the communication tube 5 that connects the discharge tube 2 and both ends of the discharge tube 2, the laser medium gas 6
The laser medium gas 6 is cooled by the heat exchanger 7 provided in the communication pipe 5, and is further circulated by the blower 8 in the arrow direction, for example. Reference numeral 9 denotes a microwave generator, and the microwave output from the microwave generator 9 is guided to the cavity resonator 1 by a waveguide (microwave transmission line) 10. The waveguide 10 has specifications suitable for transmitting the microwave output from the microwave generator 9, and the cavity resonator 1 is configured to resonate at the microwave frequency.

That is, in the conventional laser oscillation device, the microwave power output from the microwave generator 9 resonates in the cavity resonator 1 so that the electric field strength thereof is increased, and a discharge is generated in the discharge tube 2. Occur. The laser medium gas 6 is excited by this discharge, an optical resonance phenomenon occurs between the total reflection mirror 3 and the partial transmission mirror 4, and laser light 11 determined by the specifications of the laser medium gas is output.

[0005]

Since the conventional laser oscillating device is constructed as described above, there are the following problems with respect to increasing the output of laser light.

That is, in order to obtain a high output laser beam,
It is necessary to increase the microwave power input to the cavity resonator 1 or to lengthen the cavity resonator 1 and the discharge tube 2 to increase the amount of laser medium gas that can be used for laser oscillation. However, (1) If the microwave power input to the cavity resonator 1 is increased too much, the temperature of the laser medium gas 6 rises, and, for example, in a CO ₂ laser oscillator, the oscillation efficiency decreases, The laser light output may rather decrease. (2) If the cavity resonator 1 is made too long, the discharge tube 2
Instability of discharge generation in the inside, problems such as temperature rise of the laser medium gas 6 due to lengthening of the region heated by microwaves occur, and the oscillation efficiency decreases, and as in (1) In some cases, the light output may decrease. (3) The tendency of the above (1) and (2) is more remarkable as the laser oscillator is used with the cavity resonator 1 longer.

The present invention has been made in view of the above problems, and solves the problem of "it is difficult to obtain a high-power laser beam while maintaining a high laser oscillation efficiency" which is a drawback of the conventional device. , "Providing a laser oscillation device capable of obtaining high-power laser light while maintaining high laser oscillation efficiency".

[0008]

The present invention takes the following means in order to solve the above problems.

That is, (1) a microwave generator, a plurality of cavity resonators connected to the microwave generator via microwave distributors, and penetrating the cavity resonators, respectively. The
A plurality of discharge tubes sequentially arranged in succession, an optical resonator provided at the last end and the frontmost end of the row of the discharge tubes for resonating the laser light in the discharge tubes, and a laser medium gas for the discharge tubes. And a cooling heat exchanger provided at the laser medium gas outflow end of the discharge tube. (2) In the laser oscillator of the above (1), a cooling heat exchanger is provided at the laser medium gas inflow portion of the discharge tube.

[0010]

In the above means, the microwave generated by the microwave generator is distributed by the microwave distributor and supplied to each cavity resonator. The cavity resonator resonantly amplifies the input. Then, the electric field causes a discharge in the discharge tube.
The laser medium gas is excited by this discharge, an optical resonance phenomenon occurs in the discharge tube by the optical resonator, and laser light is output from one of the optical resonators.

In the above process, the laser medium gas is heated, but is not heated to a high temperature because it is circulated by the blower and cooled by the cooling heat exchanger.

Therefore, it is possible to obtain a high-power laser beam while maintaining a high laser oscillation efficiency.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) An embodiment of the invention of claim 1 will be described with reference to FIGS. It should be noted that the parts described in the conventional example are denoted by the same reference numerals and the description thereof is omitted, and the parts relating to the present invention will be mainly described.

In FIG. 1, the cavity resonators 1A and 1B are coaxially arranged. Discharge tubes 2A and 2B are provided coaxially through the cavity resonators 1A and B, respectively. The discharge tubes 2A and 2B are coaxially arranged in series. A heat exchanger 7 is provided between the discharge tubes 2A and 2B. Further heat exchanger 7
The gas outlet a is connected to the rearmost end portion b and the frontmost end portion c of the discharge tubes 2A and 2B by the gas passage 13 via the blower 8.

A total reflection mirror 3 is provided at the rearmost ends of the discharge tubes 2A and 2B, and a partial transmission mirror 4 is provided at the frontmost end thereof, which serve as an optical resonator.

The output of the microwave generator 9 is connected to the cavity resonators 1A and 1B via the microwave distributor 12 by the waveguides 10, 10A and 10B.

Details of the heat exchanger 7A are shown in FIGS.
FIG. 3 is a sectional view taken along line AA of FIG. The heat exchanger 7A has a short cylindrical shape, and fins 16 are radially arranged on the outer peripheral portion of the inner surface, and both ends of the heat exchanger 7A are channels 17A, 17B, 17C for passing a cooling medium (water) provided on the outer peripheral portion of the end surface. , 17D is connected to the side surface. Coupling flanges 19 are coaxially provided on both end surfaces, and the discharge tubes 2A and 2B are inserted therein. Further, an outlet a is provided on the side surface. 18 in the figure
A and 18B show sealing O-rings.

In the above, the microwave generated by the microwave generator 9 is distributed by the microwave distributor 12,
It is supplied to each cavity resonator 1A, 1B. Cavity resonator 1
A and 1B resonantly amplify the input. Then, the electric field causes a discharge in the discharge tubes 2A and 2B. The laser medium gas is excited by this discharge, and the discharge tube 2 is generated by the optical resonator.
An optical resonance phenomenon occurs in A and 2B, and the laser light 11 is output from the partial transmission mirror 4.

In the above process, the laser medium gas is heated, circulated by the blower 8 and cooled by the cooling heat exchanger 7A. That is, the discharge tubes 2A, 2
The laser medium gas passing through B flows along the path shown by the arrow in the figure, and is heat-exchanged and cooled in the fin 16 portion. Further, since the fin 16 is only on the outer peripheral portion, it does not interfere with the laser light.

Since the heat exchanger 7 is located at the gas outlet ends of the discharge tubes 2A and 2B, the laser medium gas is immediately guided to the heat exchanger 7 at the discharge tube outlet portion, and the laser medium gas is efficiently supplied. To be cooled. Furthermore, since the flow path length through which the high temperature laser medium gas flows is minimized, it is also advantageous for minimizing the thermal deformation of the entire laser oscillator.

2 and 3 show the outline of the structure. Depending on the required gas flow rate, heat exchange capacity, etc.,
The size and number of the fins 16, the flow paths 17A, 17B, 17C,
The 17D quantity, size, etc. are determined.

In this way, the laser medium gas is kept at a low temperature. Therefore, high-power laser light can be obtained while maintaining high laser oscillation efficiency.

Further, the laser medium gas heated to a high temperature by the microwave discharge is immediately cooled at the outlet of the discharge tube by heat exchange, so that the flow path length through which the high temperature laser medium gas flows can be minimized, and laser oscillation can be achieved. It is also advantageous for minimizing thermal deformation of the entire device. Although two cavity resonators are used in the above, three or more cavity resonators may be used.

FIG. 4 is a plot of experimental results showing the effect of this embodiment. The horizontal axis represents the output (W) from the microwave generator, and the vertical axis represents the laser light output (W) at that time. In the figure, the black circles represent the experimental results for one cavity resonator (results obtained by the conventional method), and the white circles represent the experimental results in this embodiment. As can be seen from the figure, in the conventional method, the laser light output does not increase when the microwave output is about 800 W or more, but in the present embodiment, the microwave output 13
The laser light output increases from 00 to 1400 W, and high-power laser oscillation can be obtained. (2) An embodiment of the invention of claim 2 will be described with reference to FIG. The parts described in the above-mentioned embodiments are given the same reference numerals and the description thereof will be omitted, and the parts relating to the present invention will be mainly described.

Cooling heat exchangers 7B and 7C are provided near the laser medium gas inlets of the discharge tubes 2A and 2B.
By the heat exchangers 7B and 7C, the laser medium gas is
After being cooled, it is supplied to the discharge tubes 2A and 2B.

In this way, the temperature rise of the laser medium gas is suppressed and a high power laser can be obtained.

[0027]

As described above, according to the laser oscillator of the present invention, the microwave output from the microwave generator is distributed to the plurality of cavity resonators by the microwave distributor. A discharge tube provided in each of the cavity resonators is discharged, and a laser beam is generated in each discharge tube. At this time, since the laser medium gas circulating in the discharge tube is cooled by the heat exchanger, it is possible to perform high-power laser oscillation with high efficiency without lowering the laser oscillation efficiency due to the rise of the laser gas temperature. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention according to claim 1.

FIG. 2 is a detailed view of a heat exchanger part of the embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 2 of the same embodiment.

FIG. 4 is a diagram showing an example of an experimental result of the example.

FIG. 5 is a configuration diagram of an embodiment of the present invention according to claim 2;

FIG. 6 is a configuration diagram of a conventional example.

[Explanation of symbols]

 1, 1A, 1B Cavity resonator 2, 2A, 2B Discharge tube 3 Total reflection mirror 4 Partial transmission mirror 5 Communication tube 6 Laser medium gas 7, 7A, 7B, 7C Heat exchanger 8 Blower 9 Microwave generator 10 Conductor Wave tube 11 Laser light 12 Microwave distributor 13 Gas flow path 16 Heat exchange fins 17A, 17B, 17C, 17D Cooling medium flow path 18A, 18B Sealing O-ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Abe 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (72) Inventor Minoru Danno 1 8-chome, Sachiura, Kanazawa-ku, Yokohama 1 Mitsubishi Heavy Industry Co., Ltd.

Claims (2)

[Claims] 1. A microwave generator, a plurality of cavity resonators connected to the microwave generator via a microwave distributor, and a plurality of cavity resonators penetrating the cavity resonators, respectively. A plurality of discharge tubes arranged in succession, an optical resonator provided at the last end and the frontmost end of the row of the discharge tubes to resonate laser light in the discharge tubes, and a laser medium gas to the discharge tubes. A laser oscillating device comprising a blower for circulating supply and a cooling heat exchanger provided at an outflow end of a laser medium gas of the discharge tube. 2. The laser oscillating device according to claim 1,
A laser oscillating device comprising a cooling heat exchanger provided in a laser medium gas inflow portion of a discharge tube.