Gas laser oscillator

Abstract

A gas laser oscillator having at least three discharge tubes disposed along the optical axis, and a spacer having an opening centered on the optical axis. The spacer is disposed between a partially reflective mirror and the closest discharge tube. Further, the discharge tubes are disposed in series along the optical axis, and satisfy the following three formulas simultaneously: 1 Formula 1 r1/r2 > 1.0 Formula 2 L2/(L1 + L2) < 0.85 Formula 3 r3/r2 < 1.4 where the sum of lengths of a pair of discharge tubes disposed at both ends in optical axis direction is L1, the inside diameter of these discharge tubes is r1, the sum of lengths of the other discharge tubes in the optical axis direction is L2, the inside diameter of these discharge tubes is r2, and the inside diameter of the opening of the spacer is r3.

Dependencies are inferred from the claim text.