Gas laser device

A CO2 gas laser device for amplifying CO2 laser light which repeatedly oscillates in a short pulse having a pulse width of 100 ns or less, wherein a CO2 laser gas which is excited by continuous discharge is cooled by circulating the gas by forced convection, the CO2 gas laser device comprising:

• a plurality of amplifiers, wherein an angle θ defined by an optical axis of the amplified CO2 laser light and a flow direction of the CO2 laser gas caused by forced convection (0 degree≦θ≦90 degrees) is determined by the following equation:
• θ≧arcsin(8/π×sqrt(SD)/L),
• wherein SD is a discharge cross sectional area of a volume in which the CO2 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 CO2 laser gas is interposed,
• the plurality of amplifiers including a plurality of first amplifiers and a second amplifier, the first amplifier amplifies the CO2 laser beam along a path which passes once through the CO2 laser gas, the second amplifier amplifies the CO2 laser beam along a folded path which passes at least twice through the CO2 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 CO2 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.