JPS6018153B2 - Laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser device, and more particularly to a laser device that can be miniaturized or obtain high output by providing a cooling body along the gas flow in a gas flow laser device. .

Generally, a closed cycle gas laser device is comprised of a gas circulation pump, a laser resonator, a heat exchanger, etc., as shown in FIG. 1, and gas as a laser medium is circulated.

Various types of laser devices are configured depending on the optical axis, discharge current, and gas flow direction. FIGS. 2 and 3 are partially cutaway perspective views showing the configuration of a lateral flow, lateral discharge laser device equipped with a folded resonator in which the directions of gas flow and discharge current are the same. The figure is an enlarged view of FIG. 2.

In the laser apparatus shown in FIGS. 2 and 3, a gas serving as a laser medium flows uniformly in a direction 32 of an arrow in a wind tunnel 31 formed of an insulator, and this gas flow direction 3
Electrodes 33 and 34 are arranged so as to generate discharge in the same direction as electrodes 2 and 2. On one side end surface of the wind tunnel 31, there is an entrance window 3 through which light 35 that induces concessional emission is made to enter.
6, and the light 35 incident through the entrance window 36 undergoes stimulated emission while being reflected by a plurality of reflecting mirrors 37 constituting a resonator installed on the inner surface of the wind tunnel 31, and is reflected in the gas flow 3.
2 and output from the exit window 38.
The lateral flow, lateral discharge laser device configured in this manner can obtain a high output of several kilowatts or more per discharge length lw.

However, in order to satisfy the increase in laser output, it is necessary to further increase the discharge length, so the wind tunnel must be made larger and the entire laser device must be made larger. However, by making the wind tunnel larger, it is necessary to increase the capacity of the blower to circulate the gas, and to devise the cross-sectional shape of the wind tunnel and the structure of the blower.
From a hydrodynamic point of view, it is difficult to obtain a uniform flow velocity in a wind tunnel, and in terms of discharge, it is difficult to obtain a uniform discharge. In addition, the laser output PL depends on the extraction efficiency,
If the electrical input is PE, then PL=-P8, and if the efficiency is constant, the laser output can be further increased by increasing the electrical input PE, and a high-output laser device can be obtained.

However, in reality, most of the energy other than the laser output changes into thermal energy, so increasing the input of air causes a rise in the temperature of the gas, which is the laser medium. This temperature rise causes a decrease in output due to various causes such as deformation of the reflecting mirror or distortion of the resonator due to heat transfer from the laser medium, and the device has the drawback of unstable output. . In addition, in carbon dioxide C02 lasers, the temperature rise of the laser medium causes a state in which the number of atoms or molecules at lower energy levels increases, creating a state that prevents population inversion from occurring. In order to maintain the population inversion state, the temperature rise must be kept below a certain temperature.

This invention was made in view of the above drawbacks.
It is an object of the present invention to provide a laser device which can be made smaller or which can obtain high output by providing a cooling body for gas cooling in a wind tunnel. Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a partially cutaway perspective view showing an outline of the laser device according to the present invention, which has almost the same configuration as the conventional laser device shown in FIG. 3, especially in the direction of laser discharge. A plurality of gas cooling flat plates 41 as shown in FIG. 4b are provided in the same direction.

Hereinafter, the same parts as in FIG. 3 will be explained using the same reference numerals. That is, in FIG. 4, the arrow 32 flowing inside the wind tunnel 31
By providing a plurality of gas cooling flat plates 41 so as to divide the gas flow indicated by , the gas flowing along the gas cooling flat plates 41 is forcibly cooled. At predetermined locations on this gas cooling flat plate 41, there are through holes 42 of sufficient size to allow the incident light 35 or the light from the reflecting mirror 37 to pass through, and to prevent laser loss from becoming large.
is provided. Therefore, the light enters from the entrance window 36, passes through the through holes 42 of each gas cooling flat plate 41,
It is output from the exit window 38. Furthermore, this gas cooling flat plate 41 can be made more effective by using a material such as beryllia, which is an electrical nonconductor and has good thermal conductivity. The laser device shown in FIG. 4 is a high-speed flow type device, and since the laser medium is flowing at high speed, the average heat transfer coefficient in the gas cooling flat plate 41 is approximately 0.0% of the flow velocity. Cooling can be efficiently achieved by increasing the number of boxes and fruits. In this way, by providing the gas cooling flat plate 41 in the wind tunnel 31 through which gas circulates, the gas can be efficiently cooled.

Therefore, it is possible to increase the electrical input of the laser without reducing the output due to the rise in temperature. Furthermore, by providing a gas cooling flat plate, the laser tube can be configured to be smaller for a specific electrical input when obtaining a predetermined laser output, so the entire laser device can be configured into a 4-inch type. can do. Also, the gas cooling flat plate 4
1 is provided so as to separate each discharge area formed by the plurality of electrode pairs 33 and 34 from each other, so that it not only functions as a heat radiation fin but also acts as a discharge guide at the same time. In a conventional device without such a discharge guide, a phenomenon occurs in which discharge occurs at a point other than the paired electrodes, and the discharge center is concentrated in a part of the device.
However, according to the present invention, since the discharge is uniformly performed within the integrated circuit, it is possible to improve the laser output. FIG. 5 shows an embodiment in which the cooling plate according to the present invention is used in a laser device with a slow gas flow.

That is, gas serving as a laser medium circulates in the direction of the arrow 52 in the wind tunnel 51, and a plurality of gas cooling flat plates 53 are provided to split the gas flow in the same direction as this gas flow. ing. Electrodes 54 and 55 are provided in the same direction as the gas flow. The incident light that has entered through the entrance window 58 provided in the wind tunnel 51 is emitted to the outside of the wind tunnel 51 through the through hole 59 provided in the gas cooling flat plate 53 and the exit window 60 of the wind tunnel 51 while undergoing stimulated emission. Ru. Then, the direction is further changed by reflecting mirrors 61 and 62,
It enters the wind tunnel 51 again from another entrance window 63,
Through hole 5 of gas cooling flat plate 53 with stimulated emission
9 and another exit window 64 to the outside of the wind tunnel 51 . In the above explanation, the cooling plate shown in FIG. 4b is used in the wind tunnel, but the cooling plate according to the present invention may be formed in other shapes as long as it can cool the gas. good.

Then, it is installed along the gas flow in such a manner that it does not block the flow of the gas flow. For example, in order to increase the cooling area and improve the cooling efficiency, the cooling plate may be formed with a curvature as shown in FIG. As explained above, according to the present invention, there is provided a laser medium flowing at a predetermined speed, at least one pair of electrodes provided in the laser medium, and a device for extracting laser light excited by the discharge between the electrodes. Since it is possible to obtain a laser device equipped with an optical system and a cooling plate with good thermal conductivity that is provided along the flow of the laser medium in the discharge portion in the laser medium, it is possible to obtain a laser device with four types or It has the effect of being able to obtain high output.

[Brief explanation of the drawing]

Fig. 1 is a block diagram for explaining the configuration of a general gas laser device, and Fig. 2 is a partially cutaway perspective view showing the configuration of a conventional transverse flow and transverse discharge laser device equipped with a folded resonator. , Figure 3 is an enlarged view of Figure 2, Figure 4 a, b
1 is a perspective view for explaining one embodiment of a laser device according to the present invention, in which a is a partially cutaway perspective view when applied to a lateral flow and lateral discharge laser device equipped with a folded resonator; b 5 is a perspective view for explaining the cooling flat plate according to the present invention, and FIG. A discharge laser, b is a sectional view when applied to a machine direction discharge laser and a transverse direction discharge laser, respectively, and FIG. 6 is a perspective view for explaining another embodiment of the cooling body according to the present invention. 31,51...wind tunnel, 32,52...gas flow, 33,34,
54, 55... Electrode, 36, 58, 63... Entrance window, 38, 60, 64... Exit window, 41, 53... Cooling body. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Figure 6

Claims (1)

[Claims] 1. A plurality of electrode pairs arranged in parallel in the laser medium so that discharge is generated in the same direction as the flow direction of the laser medium flowing in one direction in the wind tunnel, and a laser excited by the discharge between these electrode pairs. and an optical system including a resonator for extracting light in a direction transverse to the flow of the laser medium, wherein a cooling plate is provided along the discharge direction so as to separate each discharge region formed by the plurality of electrode pairs from each other. A laser device characterized in that the cooling plate is provided with a through portion through which the laser beam can pass through.