Electrodes for generating a stable discharge in gas laser system
Arcing is minimized in a discharge chamber of a gas laser system by utilizing an electrode which comprises a surface portion capable of functioning as one of an anode and a cathode in order to energize a gas mixture in a discharge chamber of the gas discharge laser system, a shoulder portion being positioned on either side of the surface portion and being exposed to the gas mixture, and a coating layer made of electrically insulating material, wherein the coating layer is attached to the shoulder portion by a cold spraying method.
1. A gas laser, comprising:
an electrode assembly including first and second electrodes arranged face-to-face, leaving a gap therebetween such that when electrical power is applied to said electrodes and laser gas flows in said gap, a gas discharge is struck in said gap; and
wherein at least one of said electrodes is formed from a solid conductive material having a generally hemispherical configuration including a narrow central surface portion and opposed continuous curved shoulder portions flanking the central surface portion and wherein said shoulder portions are coated with a uniform, thin layer of a non-porous ceramic wherein the thickness of the layer is less than about 1 mm and wherein said central surface portion which is exposed to the laser gas is left uncoated.
2. A laser as recited in claim 1 , wherein the ceramic material is coated onto the shoulder portions by a cold spraying method.
3. A laser as recited in claim 1 , wherein the ceramic material is aluminium(III) oxide.
4. A laser as recited in claim 1 , wherein the central surface portion has an average surface roughness of at least 100 microns.
5. A gas laser, comprising:
an electrode assembly including first and second electrodes arranged face-to-face, leaving a gap therebetween such that when electrical power is applied to said electrodes and laser gas flows in said gap, a gas discharge is struck in said gap; and
wherein at least one of said electrodes is hemispherical having a narrow central surface portion and opposed shoulder portions flanking the central surface portion and wherein the central surface portion has an average surface roughness of about 100 microns.
6. A laser as recited in claim 5 , wherein the central surface portion is in the form of a raised ridge.