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Plasma Guides and Shields for He/Ne Gas Lasers

IP.com Disclosure Number: IPCOM000085934D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Chance, DA: AUTHOR [+3]

Abstract

A commercially available, medium power, coaxial He/Ne gas laser tends to have its life reduced, because its design causes plasma flow from a small opening in the bore support tube to impinge directly on the cathode over a small area. Such localized impingement results in deterioration of the cathode due to the high density of the ions. By a judicious location of shields within the laser, the area of the cathode that is impacted is increased, reducing the current concentration at the cathode, which in turn diminishes the cathode sputtering that leads to tube failure.

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Plasma Guides and Shields for He/Ne Gas Lasers

A commercially available, medium power, coaxial He/Ne gas laser tends to have its life reduced, because its design causes plasma flow from a small opening in the bore support tube to impinge directly on the cathode over a small area. Such localized impingement results in deterioration of the cathode due to the high density of the ions. By a judicious location of shields within the laser, the area of the cathode that is impacted is increased, reducing the current concentration at the cathode, which in turn diminishes the cathode sputtering that leads to tube failure.

Fig. 1 is a partial view of the coaxial laser wherein the right end is shown having a mirror 2 that closes off a tubular member 4 having an opening 6 therein. At the other end of the laser is another mirror and an anode, not shown, for completing the laser. A cylindrical bore 8 is fitted into the tubular member 4 and a cathode 10 is circumferentially disposed about the bore 8 and lies within the glass enclosure 12 of the laser.

In order to avoid the plasma stream from impinging upon the cathode 10 as soon as it exits from opening 6, a hollow tubular glass member 14 is inserted. Due to this insertion, the plasma must flow over a larger area of the cathode 10 near the region 16 so as to diminish, if not avoid, the cathode sputtering that occurs in the absence of such shield.

Fig. 2 is another embodiment using an internal shield 14 where the shield is curved...