JPH0543490Y2 - - Google Patents

Description

[Detailed explanation of the idea]

【0001】

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a laser device, and more particularly, to a laser device between a pair of electrodes used to insulate a catalyst powder from a strong electric field existing within a laser enclosure and to excite a laser gain medium. The present invention relates to a laser device having a catalyst container that protects the catalyst medium from shock waves caused by the discharge of the catalyst, while at the same time allowing sufficient contact of the gain medium with the catalyst.

【0002】

BACKGROUND OF THE INVENTION The active medium of a CO ₂ laser is a gas mixture of carbon dioxide, nitrogen, helium, sometimes mixed with other gases, such as carbon monoxide or xenon. When an electrical discharge occurs in the gas, it excites the active medium and some of its components dissociate. In particular, CO ₂ dissociates into CO and oxygen. This dissociation of gas reduces the volume of the active medium, which is a major cause of failure in sealed CO ₂ lasers.

[0003] Attempts to reduce the deleterious effects of gas dissociation have included, for example, storing and using large amounts of gas;
This was done by making use of the catalytic action of the dissociated components. The most used technology in _CO2 lasers uses catalysts to promote the recombination of dissociated components. Carbon monoxide and nitrogen do not recombine at room temperature, but under certain conditions and in the presence of certain catalysts. Although platinum is a well-known catalyst, it requires operating the laser at elevated temperatures that are not suitable for sealed CO ₂ lasers. A commercially available mixture of manganese oxide (MnO ₂ ) and cuprous oxide, such as Hopcalite, may be used as a catalyst. The biggest problem is that the catalyst powder is dispersed throughout the laser envelope, reducing the efficiency of the laser, especially if some of the catalyst powder is deposited on the optical system.

[0004] Appl.Phys.Letters32, June 1978
“Sealed” by RBGibson et al.
Multiatmosphere CO ₂ TEA Laser: Seed−
Gas compatible system using unheated oxide
"catalyst" refers to a laser device in which the catalyst powder must be confined outside the main laser enclosure and the gas passed through the catalyst powder must be circulated.

[0005]

[Summary of the invention] The invention places a catalyst within a sealed resonant cavity, insulates the catalyst powder from the strong electric field present within the resonant cavity, and uses a pair of The present invention provides a catalyst container in which the gain medium can sufficiently catalyze the catalyst while protecting the catalyst from shock waves caused by discharge between the electrodes of the catalyst. The container is formed from an electrically conductive solid housing and a conductive cover that is permeable to the gain medium and impermeable to the catalyst therein. The container is positioned within the resonant cavity in close proximity to the discharge region to provide sufficient contact between the catalyst and the dissociated components formed by the discharge. More desirably, the container is in contact with one of the electrodes. With such a configuration, the heat generated in the electrode by the discharge is transferred to the catalyst via the container, increasing the recombination rate.

【0006】

EXAMPLES The present invention will be described in detail below with reference to Examples.

[0007] Referring to FIGS. 1A to 1C, the closed type
A CO ₂ lateral electric field atmospheric pressure (TEA) laser 10 is shown. The enclosure 12 is used to house the gain medium 13 and the two main electrodes 14 and 16.
Electrode 14 is attached to one wall of enclosure 12 and is separated therefrom by screw 20 and spacer 18 . Electrode 16 is attached to the opposite wall of enclosure 12 by screws 20 and separated from that wall by spacer 22 and catalyst vessel 40. The relative sizes of spacer 18, spacer 22, and catalyst vessel 40 define the spacing between electrodes 14 and 16, and are selected to a predetermined spacing to suit the requirements of a particular application. Catalyst vessel 40 is formed from a trough housing 26 and an end cover 28. The housing 26 is made of a solid conductive material, such as aluminum, and the cover 28 is made of a conductive material, such as a stainless steel copper screen with a predetermined mesh size, having a predetermined opening. The function of the cover 28 will be described later, but
Suffice it to say here that the cover 28 allows the gain medium 13 or its components to pass freely therethrough, while preventing the catalyst from passing even its smallest particles out of the container. The catalyst container 40 is
It is assembled inside the laser enclosure 12 by securing the base of the housing 26 to the back side of one of the electrodes, and also to the edges of the housing 26, cover 28, and spacer 22. this is,
For example, laser enclosure 12, housing 26,
Screws 20 are inserted into the corresponding holes of the cover 28 and the electrode 16.
It is completed by tightening it. Spacer 24
is used to add rigidity between the cover 28 and the inner surface of the housing 26 and to seal the contents of the container 40 from the threaded hole. A spacer 22 is used between the cover 28 and the wall of the enclosure 12 to maintain sufficient volume or space to allow the gain medium 13 to circulate past the cover 28. A mixture of manganese oxide and Daiichi steel oxide, such as hopcalite, is used as a catalyst. The catalyst may be in the form of a loose powder or compacted into pellets of suitable size. The catalyst vessel 40 and electrode 16 allow the gain medium to circulate and contact the cover 28 of the vessel 40 . The cover 28 of the container 40 has a mesh size that allows the catalyst powder to pass through but not the gain medium to pass through. Thus, although the gain medium 13 can enter the cover 28 and come into contact with the catalyst powder 30, even the smallest particles of the catalyst powder 30 cannot pass through the cover 28 and into the gain medium 13, and are not allowed to pass through the cover 28 and into the delicate optics of the laser. particles will not accumulate on the surface. Typically a 40 micrometer mesh
size is used.

[0008] A discharge control device 60 is provided to cause a discharge between electrodes 14 and 16 to excite gain medium 13 and generate a laser pulse. When used in resonator mode, a total internal reflection mirror 50 reflects the laser 10 at one end of the enclosure 12.
, and a partially transparent mirror 52 is located on the optical axis opposite the enclosure 12 . In another application, mirrors 50 and 52 are replaced with optical output windows, the faces of which are positioned at Brewster's angle to the optical axis, and the polarity of the output laser pulses controlled in a known manner.

During operation of the laser, the presence of a strong electric field causes the catalytic pellets 30 to break up, creating a dispersing effect on the catalytic powder. This can degrade the operation of the laser, especially if the powder is deposited on the optical elements within the laser enclosure 12. The electrodes 14
An electrical discharge occurring between the electrodes 16 creates shock waves which have the detrimental effects on the catalyst as previously described. The housing 26 and cover 28 form a conductive cage, sometimes called a Faraday cage.
It has been found that this protects the catalyst 30 from the dissipative effects of the strong electric fields present within the laser enclosure.
It also protects the catalyst 30 from shock waves generated by the discharge between the main electrodes 14 and 16, and prevents the amount of catalyst particles in the container 40 from being reduced.

[0010] The turbulent flow of gas caused by the discharge between the main electrodes 14 and 16 is sufficient to provide adequate catalysis of the gain medium 13 and the catalyst 30 when placed in close proximity to the discharge region. I can understand.
That is, since the catalyst 30 is placed within the resonant cavity,
The recombination rate can be increased. enclosure 1
container 4 extending between one of the side walls of 2 and the electrode 16;
The 0 position also has the advantage that the container 40 is easy to install. By using screws 20 and spacers 22 and 24, container 40 can be firmly and securely attached.

[0011] The discharge control device 60 includes the electrodes 14 and 16.
and selectively control the repetition rate. The repetition rate of the electrical discharge is one of the variables that determines the temperature within the laser enclosure. The MnO component of the catalyst powder becomes more effective in the lower temperature range that occurs during low repetition rate operation of the laser, and the CuO component becomes more effective in the higher temperature range that occurs during high repetition rate operation. It combines to enable the catalytic action of the dissociated gas over a wider temperature range, giving some freedom in the choice of pulse repetition frequency. The repetition frequency is also limited by the fact that the rate of gas dissociation by the discharge cannot exceed the rate of recombination by the catalyst.

[0012] As shown in FIGS. 1A and 1B, the catalyst container 40 is in contact with the electrode 16. This arrangement allows heat from the electrode 16 to be transferred to the container 40;
Then, it is transmitted to the catalyst 30. This causes the temperature of the catalyst 30 to rise and the catalyst to effect the rate of recombination. The electrical discharge between electrodes 14 and 16 generates heat in the electrodes. If a DC discharge is used, the cathode will generate more heat than the anode. And in order to achieve the maximum recombination rate, Figure 1
The catalyst container 40 must be in contact with the cathode, such as the electrode 16 shown in FIG. In the case of non-DC discharges, the position of the vessel 40 is less critical as long as there is an effective thermal coupling to one of the electrodes, ie by heat transfer.

[0013] It will be apparent to those skilled in the art that various modifications can be made to the embodiments of the present invention within the scope of the present invention. For example, the actual location and specific shape of container 40 may be changed to suit a particular enclosure. It is sufficient that the container 40 is thermally coupled to one electrode substantially in the discharge region. Therefore, the present invention is not limited to the embodiments described above.

[Brief explanation of the drawing]

FIG. 1A is a sectional view of a laser device according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line 1B-1B in FIG. 1A. FIG. 1C is a top view of the catalyst container used in the embodiment shown in FIG. 1A.

[Explanation of symbols]

12...Surrounding body, 13...gain medium, 14, 16...electrode, 18, 22...Spacer, 30...Catalyst, 40... Container, 60...Discharge control device.

Claims (1)

[Scope of utility model registration request] 1. An active fluid gain medium; a sealed resonant cavity surrounding the active fluid gain medium; a catalyst disposed within the sealed resonant cavity; an electric field generated within the resonant cavity; means for protecting the catalyst from shock waves, the means comprising an electrically conductive container in which the catalyst is disposed, and having a portion on a surface of the container that allows the gain medium to pass through but does not allow the catalyst to pass through; laser equipment.