| 摘要 |
PURPOSE:To enable operation stably even by highly repetitive laser oscillation by forming a communicating section communicated with a cavity to a sidewall on the upstream side of a gas laser medium to the circulating gas laser medium in an electrode to which a pre-ionization electrode is disposed. CONSTITUTION:An anode 2 and a cathode 22, the inside of which has a cavity 6 while being opposed to the anode 2 and to the surface of which opposed to the anode 2 a plurality of pre-ionization holes 7 communicated with the cavity 6 are shaped, are mounted into a laser tube 1 into which a gas laser medium is sealed, and a pre-ionization electrode 8 forming glow discharge between the cathode 22 and the electrode 8 is arranged into the cavity 6. A communicating section 23 communicated with the cavity 6 on the inside of at least the upstream-side sidewall of the cathode 22 to the gas laser medium circulating in the electrode 8 is shaped to at least the upstream-side side surface of the cathode 22. Since not only a section between both the cathode and the anode forming main discharge but also the gas laser medium in the cavity 6 for the cathode 22 can be replaced, the generation of arc discharge between both the cathode and the anode can be prevented even by highly repeated laser oscillation. |
