CN102709795A - Helium-neon gas laser with built-in cavity - Google Patents

Abstract

The invention relates to a helium-neon laser with a built-in cavity, which is characterized in that it includes a glass tube shell and two concave connectors made of Kovar metal materials, the concave Kovar connectors include a supporting structure and a positioning structure, and the positioning structure ends A concave connection block is set at the bottom; a cathode cylinder is arranged inside the glass tube shell, and the outer wall of the cathode cylinder is bonded to the inner wall of the glass tube shell. The tube and the concave connection block are sintered into one body, and a capillary is arranged in the glass tube shell, and the two ends of the capillary are respectively inserted in two positioning structures; a concave kovar connector is provided with a total reflection mirror and a spring in sequence from the inside to the outside. And the window, and this concave kovar connector is connected to the positive pole of the high-voltage power supply; the other concave kovar connector is provided with output mirror, spring and window sequentially from the inside to the outside, each window and each concave can After the ends of the connecting piece are fixed, the total reflection mirror and the output mirror are respectively pressed against the two ends of the capillary by squeezing the two springs. The invention can be widely used in the manufacture of helium-neon lasers.

Description

A built-in cavity helium-neon laser

technical field

The invention relates to a laser, in particular to a helium-neon laser with a built-in cavity.

Background technique

The cavity mirror in the traditional helium-neon laser resonator structure is sintered together with Kovar material and glass shell at high temperature (the expansion coefficient of Kovar material and glass shell material is similar), and different materials sintered together at high temperature generally generate internal stress. When the temperature changes, these internal stresses will be amplified to varying degrees. This kind of resonant cavity structure has the following problems: 1. During the working process of the He-Ne laser, the heat generated by different parts will be different. The specific performance is: the cathode The cylinder is hot and the anode is cold; the top of the glass shell is hot and the bottom is cold. This temperature gradient causes different parts of the laser to expand to different degrees, resulting in the two cavity mirrors in the resonator not being parallel, and the expansion coefficients of different materials are different. The distortion and deformation of the resonant cavity further exacerbate the influence of the temperature gradient on the non-parallel effect of the two cavity mirrors. 2. Under normal circumstances, the output power of the He-Ne laser will fluctuate violently in a large range when it first starts working. When the parts of the laser shell gradually reach thermal equilibrium over time, the output power of the laser will be relatively stable and fluctuate. It will also be more regular. Under the influence of temperature gradient, the internal stress generated by high-temperature sintering makes the creeping state of the two-cavity mirror of the resonator more unpredictable, which seriously affects the stability of the output power of the laser.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a built-in resonator that can effectively solve the distortion and deformation of the resonant cavity caused by the different expansion coefficients of different materials, and ensure that the two cavity mirrors of the resonant cavity are parallel and have good light output power stability. cavity helium-neon laser.

To achieve the above object, the present invention adopts the following technical solutions: a built-in cavity helium-neon laser, characterized in that it includes a glass tube shell and two concave kovar connectors with openings at both ends made of kovar metal material, Each of the concave connectors includes a supporting structure and a positioning structure integrally formed with the supporting structure, and a circle of concave connecting blocks is provided at the end of each positioning structure; A cathode cylinder, the outer wall of the cathode cylinder is attached to the inner wall of the glass tube shell, and the cathode cylinder passes through the glass tube shell through a tungsten rod to connect to the negative electrode of a high-voltage power supply. The two ends of the glass tube shell The two concave connection blocks of the positioning structure are respectively sintered into one body through a connecting tube, and a capillary is also arranged in the outer shell of the glass tube, and the two ends of the capillary are respectively inserted in the positioning positions of the two concave connectors. In the structure: a said concave kovar connector is provided with a total reflection mirror, a spring and a window sequentially from the inside to the outside, and the said concave kovar connector is connected to the positive pole of the high-voltage power supply through a metal wire ; Another said concave kovar connector is provided with an output mirror, a spring and a window in sequence from inside to outside, after each said window is fixed with the end of each said concave kovar connector By squeezing the two springs, the total reflection mirror and the output mirror are respectively attached to the two ends of the capillary.

An anode discharge hole and a cathode discharge hole are arranged on the capillary, the anode discharge hole is aligned with the positioning structure of a concave Kovar connector, and the cathode discharge hole is aligned with the cathode cylinder; the anode discharge hole A discharge channel is formed between the cathode discharge hole and the positive and negative poles of the high voltage power supply.

The two ends of the capillary are concave, and the concave is chamfered, so that the contact parts of the total reflection mirror and the output mirror and the capillary are in line contact.

The total reflection mirror and the output mirror form a resonant cavity, and the resonant cavity adopts a flat concave cavity.

The total reflection mirror is a concave mirror, and the concave surface is coated with a high-reflection film. The output mirror is a birefringent plane mirror. The inside of the birefringence plane mirror is coated with an anti-reflection film, and the outside is coated with a high-reflection film.

The total reflection mirror is a plane mirror, the inner side of the plane mirror is coated with a high-reflection film, the output mirror is a birefringent concave mirror, the concave surface is coated with an anti-reflection film, and the plane is coated with a high-reflection film.

An exhaust hole is also arranged on the glass tube shell, and the expansion coefficients of the glass tube shell, the connecting pipe and the concave kovar connector are equivalent.

The present invention has the following advantages due to the adoption of the above technical scheme: 1. The present invention comprises a glass tube shell, two concave shaped connectors and a capillary, and the two ends of the glass tube shell pass through a connecting tube and two concave shaped connectors respectively. The connecting parts are fixed together, and the cavity mirror (total reflection mirror or output mirror), spring and window are arranged in sequence in each concave kovar connecting part, and each window and each concave kovar connecting part After the end is fixed, the total reflection mirror and the output mirror are respectively attached to the two ends of the capillary by squeezing the spring. Since the present invention fixes the cavity mirror by means of spring compression, compared with the prior art, the cavity mirror no longer passes through the capillary. The method of high-temperature sintering is connected with the glass shell, which not only reduces the adverse effects of materials with different expansion coefficients on the parallelism of the cavity mirror when the temperature changes, but also eliminates the problems of creep and deformation of the cavity mirror caused by internal stress generated by high-temperature sealing . 2. The glass shell of the present invention and the internal stress generated by sintering between the glass shell and the concave Kovar connector can be effectively absorbed by the spring, which has almost no impact on the "relatively independent resonant cavity", so that the output power of the laser The stability is improved by nearly an order of magnitude, and the stabilization speed of the light output power of the laser is greatly improved. The invention can be widely used in the manufacture of helium-neon lasers.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the laser of the present invention;

Fig. 2 is a schematic diagram of the installation state of the glass tube shell and the cathode cylinder of the present invention;

Fig. 3 is a schematic diagram of the installation state of the glass tube shell and the concave kovar connectors at both ends of the present invention;

Fig. 4 is a schematic diagram of the installation state of the output mirror and the spring-enclosed concave Kovar connector of the present invention;

Fig. 5 is a schematic diagram of the installation state of the capillary of the present invention;

Fig. 6 is a schematic diagram of the installation state of the total reflection mirror and the spring-enclosed concave kovar connector of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the present invention includes a glass tube shell 1 made of tungsten group glass and two concave kovar connectors 2 with openings at both ends made of kovar metal material, each concave kovar connector 2 includes a support structure 21 and a positioning structure 22 integrally formed with the support structure 21, and a ring of concave connecting blocks 23 is provided on the outside of the end of each positioning structure 22. A cathode cylinder 3 is arranged in the glass tube shell 1, the outer wall of the cathode cylinder 3 is attached to the inner wall of the glass tube shell 1, and the cathode cylinder 3 passes through a tungsten rod 4 to pass through the glass tube shell 1 and the negative electrode of the high-voltage power supply of the He-Ne laser Connection, in order to limit the axial movement of the cathode cylinder 3 in the glass tube shell 1, the connection between the tungsten rod 4 and the glass tube shell 1 is sintered into one. Both ends of the glass tube shell 1 shrink inward into a trumpet shape and are respectively fixedly connected to a connecting tube 5 . The outer end of each connecting pipe 5 is sealed with the concave connection block 23 at high temperature by radio frequency, so that each concave kovar connector 2 is fixedly connected with the glass tube shell 1 and integrated. A slender capillary 6 is arranged inside the glass tube shell 1, and the two ends of the capillary 6 are respectively inserted into the positioning structures 22 of the two concave kovar connectors 2, and the supporting structure of the concave kovar connector 2 on one side 21. A total reflection mirror 7, a spring 8 and a window 9 are sequentially arranged from the inside to the outside, and the support structure of the concave kovar connector 2 on the other side is provided with an output mirror 10 and a spring 11 from the inside to the outside in sequence. And a window 12, after each window is fixed with the end of each concave kovar connector, the total reflection mirror 7 and the output mirror 10 are respectively pressed against the two ends of the capillary 6 by pressing the spring.

In the above-mentioned embodiment, the capillary 6 is made of glass, and an anode discharge hole 61 and a cathode discharge hole (not shown in the figure) are arranged on the capillary 6, and the anode discharge hole 6 is aligned with the left concave Kovar connector 2 The positioning structure 22, the concave Kovar connector 2 is drawn out through the metal wire 62 to connect the positive pole of the high-voltage power supply of the He-Ne laser, the cathode discharge hole is aligned with the cathode cylinder 3, and the apertures of the anode discharge hole and the cathode discharge hole are slightly larger than that of the capillary 6 Inner diameter, its role is to form a discharge channel between the capillary and the positive and negative electrodes of the high-voltage power supply, and also to communicate the gas in the capillary 6 with the gas storage chamber to maintain the gas pressure in the discharge area.

In each of the above-mentioned embodiments, the total reflection mirror 7 and the output mirror 10 constitute a resonant cavity, and the resonant cavity can be a flat concave cavity, that is, the total reflection mirror 7 is a concave mirror, the concave surface is coated with a high-reflection film, and the output mirror 10 is a birefringent flat mirror. The inner side is coated with an anti-reflection film, and the outer side is coated with a high-reflection film; or the total reflection mirror 7 is a plane mirror, and the inner side of the plane mirror is coated with a high-reflection film, and the output mirror 10 is a birefringent concave mirror, and the concave (inner side) is coated with an anti-reflection film, and the plane (outer side) is coated with a high-reflection film. ) with high reflection coating.

In the above-mentioned embodiments, the cathode cylinder 3 can be made of aluminum material, and the diameter of the cathode cylinder 3 is slightly smaller than the diameter of the glass tube shell 1 .

In above-mentioned each embodiment, the contact position of capillary 6 and total reflection mirror 7 and output mirror 10 adopts line contact, can be by grinding the two end surfaces of capillary 6 out of concave surface and concave chamfering, purpose is to reduce capillary 6 and total reflection as far as possible. The contact area of mirror 7 and output mirror 10 prevents thermal lens effect.

In each of the above-mentioned embodiments, the glass tube shell 1 is also provided with an exhaust hole 13, which is used to fill and discharge gas into the glass tube shell 1, and the glass tube shell 1, the connecting pipe 5 and the concave kovar connector 2 The coefficient of expansion is equivalent.

As shown in Figures 2 to 6, the packaging process of the built-in cavity He-Ne laser of the present invention is as follows:

1. Weld and fix one end of the cathode cylinder 3 with a tungsten rod 4 and insert it into the glass tube shell 1, and pass one end of the tungsten rod 4 out of the glass tube shell 1 through "burning beads" to connect with the negative pole of the high-voltage power supply of the He-Ne laser (such as Figure 2).

2. The two ends of the glass tube shell 1 are softened and shrunk into a trumpet shape through flame roasting, and the two connecting pipes 5 are sintered on the two ends of the glass tube shell 1 respectively.

3. The two connecting pipes 5 are respectively sealed with the concave connection block 23 of each positioning structure 22 of the two concave kovar connectors 2 through radio frequency high temperature sealing, so that the two concave kovar connectors 2 are respectively connected to the glass shell 1 Connected into one (as shown in Figure 3).

4. Place the output mirror 10 and the spring 11 in the support structure 21 of the right concave Kovar connector 2 in sequence, and paste and fix the window 12 on the end of the concave Kovar connector 2 (as shown in Figure 4 Show).

5. Insert the capillary 6 through the left concave Kovar connector 2 into the positioning structure 22 of the right concave Kovar connector 2, align the cathode discharge hole of the capillary 6 with the cathode cylinder 3, and place the capillary 6 The anode discharge hole 61 is facing the positioning structure 22 of the concave Kovar connector 2 on the left (as shown in FIG. 5 ).

6. Put the total reflection mirror 7 and the spring 8 into the supporting structure 21 of the concave Kovar connector 2 on the left side in turn, and paste and fix the window 9 on the end of the concave Kovar connector 2, two The windows 9 and 12 press the two springs 8 and 11 to make the total reflection mirror 7 and the output mirror 10 close to the end face of the capillary 6 respectively, and connect the concave connector 2 on the left side through the metal wire 62 The positive electrode of the high-voltage power supply of the He-Ne laser (as shown in Figure 6).

Above-mentioned each embodiment is only for illustrating the present invention, and wherein the structure of each component and connection mode etc. all can be changed to some extent, every equivalent conversion and improvement carried out on the basis of the technical solution of the present invention, all should not be excluded from the present invention. outside the scope of protection of the invention.

Claims (9)

1. A built-in cavity helium-neon laser is characterized in that: it comprises a glass tube shell and two concave kovar connectors with openings at both ends made of kovar metal material, each of the concave kovar connectors It includes a support structure and a positioning structure integrally formed with the support structure, a ring of concave connecting blocks is provided at the end of each positioning structure; a cathode cylinder is provided inside the glass tube shell, and the outer wall of the cathode cylinder is in contact with the The inner walls of the glass tube shell are bonded together, and the cathode cylinder passes through the glass tube shell through a tungsten rod to connect to the negative electrode of a high-voltage power supply. The concave connection block of the structure is sintered into one body, and a capillary is also arranged in the outer shell of the glass tube, and the two ends of the capillary are respectively inserted in the positioning structures of the two concave kovar connectors; The connector is provided with a total reflection mirror, a spring and a window in sequence from the inside to the outside, and the concave kovar connector is drawn out through a metal wire to connect to the positive pole of the high-voltage power supply; An output mirror, a spring, and a window are sequentially arranged on the part from the inside to the outside, and each of the windows is fixed to the end of each of the concave collapsible connectors, and the two springs are squeezed to respectively make the full The reflection mirror and the output mirror are closely attached to the two ends of the capillary. 2. A helium-neon laser with built-in cavity as claimed in claim 1, characterized in that: an anode discharge hole and a cathode discharge hole are arranged on the capillary, and the anode discharge hole is aligned with a concave Kovar connector The positioning structure, the cathode discharge hole is aligned with the cathode cylinder; a discharge channel is formed between the anode discharge hole and the cathode discharge hole and the positive and negative poles of the high voltage power supply. 3. a kind of built-in cavity helium-neon laser as claimed in claim 1, is characterized in that: described capillary tube two end surfaces are set as concave surface and described concave surface chamfering, make described total reflection mirror and output mirror and described capillary tube The contact part is a line contact. 4. a kind of built-in cavity helium-neon laser as claimed in claim 2, is characterized in that: described capillary tube two end surfaces are set as concave surface and described concave surface chamfering, make described total reflection mirror and output mirror and described capillary tube The contact part is a line contact. 5. A built-in cavity He-Ne laser according to claim 1, 2, 3 or 4, characterized in that: the total reflection mirror and the output mirror form a resonant cavity, and the resonant cavity is a flat concave cavity. 6. A kind of built-in cavity helium-neon laser device as claimed in claim 5, characterized in that: the total reflection mirror is a concave mirror, the concave surface is coated with a high reflection film, the output mirror is a birefringent plane mirror, and the birefringence The inner side of the flat mirror is coated with an anti-reflection coating, and the outer side is coated with a high-reflection coating. 7. A He-Ne laser with built-in cavity as claimed in claim 5, characterized in that: the total reflection mirror is a plane mirror, the inside of the plane mirror is coated with a high-reflection film, and the output mirror is a birefringent concave mirror, and the concave surface is coated with a high reflection film. Anti-reflection coating, high-reflection coating on the plane. 8. A built-in cavity helium-neon laser as claimed in claim 1 or 2 or 3 or 4 or 6 or 7, characterized in that: an exhaust hole is also arranged on the glass tube shell, and the glass tube shell , The expansion coefficients of the connecting pipe and the female Kovar connector are equivalent. 9. A built-in cavity helium-neon laser as claimed in claim 5, characterized in that: a vent hole is also arranged on the glass tube shell, and the glass tube shell, connecting pipe and concave Kovar connector The coefficient of expansion is comparable.

Images