Patent ID: 8885684

Claim:
A CO 2 gas laser device for amplifying CO 2 laser light which repeatedly oscillates in a short pulse having a pulse width of 100 ns or less, wherein a CO 2 laser gas which is excited by continuous discharge is cooled by circulating the gas by forced convection, the CO 2 gas laser device comprising: a plurality of amplifiers, wherein an angle θ defined by an optical axis of the amplified CO 2 laser light and a flow direction of the CO 2 laser gas caused by forced convection (0 degree≦θ≦90 degrees) is determined by the following equation: θ≧arcsin(8/π×sqrt( S D )/ L ), wherein S D is a discharge cross sectional area of a volume in which the CO 2 laser gas is excited by discharge, and L is a discharge length of the volume, the plurality of amplifiers each including discharge electrodes which are opposite to each other, between which the CO 2 laser gas is interposed, the plurality of amplifiers including a first amplifier and a second amplifier, the first amplifier amplifies the CO 2 laser beam along a path which passes once through the CO 2 laser gas, the second amplifier amplifies the CO 2 laser beam along a folded path which passes at least twice through the CO 2 laser gas, wherein the laser beam passing through the second amplifier first makes contact with one discharge electrode, and then makes contact with another discharge electrode opposite to the one discharge electrode, and wherein the CO 2 gas laser device further comprises a shaping optical system for supplying the laser beam having a diameter which is equal to the length of the side of the discharge cross section, to the first amplifier.