JPS60128685A - Metallic-ion laser - Google Patents

Abstract

PURPOSE:To prevent the dissipation of metal evaporation positively, and to obtain a metallic-ion laser obviating the contamination of a Brewster window by making the diameter of a positive column discharge path up to an auxiliary anode from the end section of a hollow cathode, to which a main anode is disposed, thinner than the bore diameter of the cathode and making it approximately the same as that of a glow region generated in a bore. CONSTITUTION:Voltage is applied among main anodes 5a-5c and auxiliary anodes 6a, 6b and a hollow cathode 4, and negative glow discharge is generated among the main anodes and the hollow cathode. Cd vapor is generated by the heat loss of negative glow discharge on a He-Cd laser using Cd as a metallic- ion generating material 9, and Cd vapor is transferred to a high energy level by excited particles of He ions, etc. Since the hollow cathode 4 is formed by a thick pipe at that time, it has large thermal conduction and heat capacity, temperature distribution in a laser pipe 1 is equalized, and transfer to arc discharge from abnormal glow discharge is prevented. Since spaces among the main anodes 5a-5c are set to narrow width, a cathode surface 13 in the hollow cathode 4 is sputtered with He ions at all times, and the state of the cathode surface 13 is cleaned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention J] The present invention provides a method for manufacturing a Brewster window using metal vapor t by simplifying the structure.
The present invention relates to a metal ion laser which has been subjected to a V-voltage treatment in order to be reliably protected from such contamination.

[Conventional technology] In recent years, metal ion lasers using hollow cathode discharge [
It is heavily suggested. This type of laser is capable of multicolor oscillation due to its excitation intensity, and currently 12 oscillation lines have been observed in the He-CD ionizer, including the three primary colors of light, red and blue.

It contains green color and has excellent characteristics not found in liquid lasers and solid-state lasers, and is expected to be applied to devices such as printers and copiers, but it has not yet reached the point of practical use. is the reality. There are various possible causes for this, but the main one is that metal vapor is handled in the V-zer active region, so gold vapor adheres to the cathode surface and Brewster window, constantly maintaining the initial state. This seems to be because the operating characteristics change over time, making it impossible to ensure output stability. In particular, in order to protect the Brewster window, the V-ser tube uses the electrophoretic effect of the discharge from the auxiliary anode to blow back the metal vapor in the bore from both ends of the bifurcated hollow cathode to prevent it from dissipating. [The positive column discharge channel, which has the same diameter as the Boa Boa, was not able to blow back sufficiently.

Therefore, it has been proposed to provide a metal vapor condensing section in front of the Brewster window as a condensing panfuru to prevent metal vapor from dissipating (see Japanese Patent Laid-Open No. 57-32689).
However, in such a structure, the laser tube itself is complicated and assembly workability is poor, and the condensation section increases the size of the laser tube.

[Summary of the invention]

The present invention has been made in view of the above-mentioned points, and the cathode bore is designed so that the diameter of the positive column discharge path in the auxiliary anode section is equal to the diameter of the glow region in the cathode bore that contributes to the laser amplification effect. A metal ion laser with an extremely simple configuration that more reliably prevents dissipation of metal vapor and prevents contamination of the Brewster window. It provides:

[Embodiment 11] Hereinafter, the present invention will be explained in detail based on the drawings and practical examples.
I will clarify the situation on +.

FIG. 1 is a sectional view showing an embodiment of a metal ion laser according to the present invention, and FIG. 2 is an enlarged sectional view of a main part of the laser. In these figures, 1 is a laser tube filled with salt gas, 2 and 3 are Brewster windows, 4 is a hollow cathode, and 5 is a laser tube filled with salt gas.
a, 5b, 5c are main anodes, 6a, 6b are auxiliary anodes, I is an insulator, 8A, 8B is a reservoir for metal ion generating material 9,
10 is a positive column discharge path, 11 is a glow region, 1-2 is a cathode dark area, 13' is a cathode bore, and 4' is an outer tube of the hollow cathode 4.

The hollow cathode 4 is formed of a thick-walled conductive pipe made of stainless steel, for example, and its center hole constitutes a cathode bore 13' in which the glow region 110 is generated, and the three main anodes 5a are formed on the circumferential surface of the hollow cathode 4. , 5b, and 5c are arranged at equal intervals in the axial direction of the cathode 4. These main anodes 5a,
The interval between 5b and 5c is relatively narrow, for example, the active length is 30 cm.
, the bore diameter (D) is set to about 2 cm in the case of 3.5 Can. The reservoirs 8A and 8B are annular grooves formed on the outer peripheral surface of the hollow cathode 4 on both sides of the central main anode 5b, and the metal ion generating material 9 is placed in these reservoirs 8A and 8B, respectively. It is accommodated. Further, each of the reservoir portions 8A.

8B is a circumferential line formed on the surface 13 of the cathode bore 13' of the hollow cathode 4. It is communicated with the glow region 11 through 14A and MB. In this way, each of the reservoirs 8A and 8B can be substantially separated from the glow region 11, and plasma can be prevented from entering.

The auxiliary anodes 6a, 6b are connected to the Brewster window 2.3.
A force of 1 is applied to the insulating camps 15a and 15b coaxially connected to both ends of the hollow cathode 40 through the insulator 7, and a force of 1 is applied to each of the anodes 6a and 6.
b is provided apart from the main anodes 5a and 5c on both sides. The diameter d of the center hole 16 of each insulation camp 15a, 15b is set to be equal to the value obtained by subtracting the thickness of the cathode dark part 12 from the bore diameter.

The insulators 7 of the main anodes 5a, 5b, and 5c are made of ceramic or the like, and the insulators 7 are formed in the anode mounting hole of the hollow cathode 4 (Fig. (not shown) is fitted from the outside and fixed by argon welding, etc., and each of the main anodes 5a, 5b, 5 is located at the center of the inner end surface.
A recess 1T is formed to accommodate the insertion end of c. Each of the main anodes 5a, 5b.

The inner end of 5c is located within the recess 17 by a predetermined distance t from the inner edge of the insulator 7, in other words, from the cathode surface 13 of the hollow cathode 4.
It's just retracting. Incidentally, the insulators γ of the auxiliary positive images 6a and 6b are also formed in the same manner.

The upper ends of the raw hot water (iffi 5a, 5b, 5c and auxiliary heat!'M6a, 6b) are each surrounded by a glass tube 30 whose lower end is fitted into a recess formed in the upper surface of the insulator 7. This glass tube 30 is used to prevent discharge between each of the anodes and the surface of the hollow cathode 4, and the distance between the glass tube 30 and the corresponding anode is set to prevent bending due to thermal expansion of the anode. Appropriate dimensions are maintained within a range where the two do not come into contact with each other.

Next, the laser operation in such a configuration will be explained.

A required voltage is applied between the raw water In5a, 5b, 5c1, the auxiliary anodes 6a, 6b, and the hollow cathode 4, and a negative glow discharge is generated between the main anodes 5a, 5b, 5c and the hollow cathode 4. Here, metal ion generating material 9
To explain the case of a He-Cd laser using CD as an example, CD vapor is generated by the scorching of the negative glow discharge, and this is transferred to a higher energy level by excited particles such as He ions.

In this case, since the hollow cathode 4 is formed of a thick-walled pipe, heat conduction and heat capacity are large, and the laser tube 1
Since the temperature distribution within the area is made uniform, abnormal glow emission '(L
The transition from to arc discharge is prevented.

Moreover, since the intervals between the main anodes 5a, 5b, and 5c are set narrowly, the cathode surface 13 of the hollow cathode 4 is
Ions constantly sputter and clean the cathode surface 13. Further, since the positive column discharge path 12 and the respective reservoirs 8A, 8B are communicated with each other through the slits 14A, 14B, and the reservoirs 8A, 8B are substantially separated from the glow region 11, the plasma can flow through the respective reservoirs 8A. , can be prevented from entering 8B. Therefore, there is no possibility that an excessive amount of CD vapor is generated due to sputtering of I8 ions, and the CD vapor pressure can be controlled only by the cathode temperature.

Further, a recess 17 is provided on the inner end surface of the insulator 7, and this recess 7
The inner ends of the raw hot water (i5a, 5b, 5c) are located inside and retracted from the hollow cathode 4, thereby preventing the cathode material from adhering to and coagulating in the recess 1T of the insulator.

That is, when the main anodes 5a, 5b, and 5c are retracted, the inner surface of the recess 17 is damaged by discharge heat, compared to when the main anodes 5a, 5b, and 5c are flush with the cathode surface 13, or when they are made to protrude from the cathode surface 13 into the positive column discharge passage 10. Since the entire cathode is baked to a temperature higher than the surrounding cathode temperature and sputtered with He ions at the same time, there is almost no adhesion of CD vapor and cathode material, and there is no possibility that the CD vapor and cathode material will get into the back of the discharge (to the back of the recess 17). The CD vapor generated is blown back by the electrophoretic effect of the positive column discharge directly below the main anodes 5a, 5b, and 5c, and is prevented from adhering to the inner wall of the recess. Therefore, the main anode 5a
, 5b, 5c and the hollow cathode 4 are not short-circuited and become at the same level, so that the initial state can be maintained well and stable discharge can be obtained. Note that the auxiliary anodes 6a and 6b also have similar effects.

Moreover, if the retraction dimension t of the anodes 5a, 5b, 5c, (ia, 5b) is too large, moving stripes will occur in the area of positive column discharge, transmitting the fluctuation to the glow discharge in the cathode bore, and causing the laser The area becomes noisy.

On the other hand, if t is made too small, the CD vapor will not blow back. Therefore, the retraction dimension t is 2rrrm
degree is considered optimal.

Each of the auxiliary anodes 5a and jib is provided with an insulating cap 15a.

Cd'72
Dissipation of Qi and Brewster Window 2, 3 due to this dissipation
However, in this case, in the present invention, as described above, the insulation camp 15a.

Since the inner diameter of 1'5b is made the same as the diameter of the negative glow region, and the ring cross section corresponding to the cathode dark part 12 in the hollow cathode 4 is eliminated, good airtightness against CD vapor can be maintained. Further protects the Brewster window 2°3. In addition, since the dissipation of CD vapor is small, the hollow cathode 4
A substantially uniform vapor density can be ensured throughout the interior of the chamber, and a uniform discharge can be obtained.

〔Effect of the invention〕

As explained above, in the metal ion laser according to the present invention, the cross-sectional area of the positive column discharge path in the auxiliary anode part is made smaller than the bore diameter of the hollow cathode part, eliminating the area corresponding to the cathode dark part. Steam airtightness is further improved, metal vapor can be prevented from diffusing and adhering to the Brewster window, and metal vapor can be easily controlled. - Also, the structure is simple, easy to manufacture, and can be provided at low cost.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a -5 embodiment of the metal ion laser according to the present invention, and Fig. 2 is an enlarged view of the main part of the laser.
It is an r-plane view. 1...Laser tube, 2,3...Brewster window, 4...Hollow cathode, 5.5a, 5b...Main 1 field pole, 6a, 6b...Auxiliary anode , 7... Insulator, 8A, 8B... Reservoir, 9... Metal ion generating material, 10... Positive column discharge path, 11...
・Glow area, 12... Cathode dark area, 13'...
Cathode bore.

Claims (1)

[Claims] In a metal ion laser that generates laser light using negative glow discharge, the diameter of the positive column discharge path between the end of the hollow cathode where the main anode is disposed and the auxiliary anode is made smaller than the cathode bore diameter. A metal ion laser-0 whose special feature is that σ is equal to the diameter of the glow region generated in the bore.