| CPC H01S 3/2325 (2013.01) [H01S 3/225 (2013.01)] | 20 Claims |
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1. A laser system comprising:
a solid-state laser device configured to output a laser beam;
an excimer amplifier including a pair of discharge electrodes arranged to face each other with a discharge space therebetween, the laser beam passing through the discharge space, the excimer amplifier being configured to amplify the laser beam;
a beam shaping unit arranged in an optical path between the solid-state laser device and the excimer amplifier, the beam shaping unit being configured to expand a beam section of the laser beam output from the solid-state laser device;
a random phase plate arranged in an optical path between the beam shaping unit and the excimer amplifier; and
a collimating optical system arranged in an optical path between the random phase plate and the excimer amplifier,
when a traveling direction of the laser beam entering the excimer amplifier is a Z direction, a discharge direction of the discharge electrodes is a V direction, a direction orthogonal to the V direction and the Z direction is an H direction, a shaping direction of the beam shaping unit corresponding to the V direction in the beam section of the laser beam entering the excimer amplifier is a first direction, a shaping direction of the beam shaping unit corresponding to the H direction in the beam section is a second direction, an expansion rate in the first direction is E1, and an expansion rate in the second direction is E2, the beam shaping unit expanding the beam section of the laser beam such that an expansion ratio defined by E2/E1 is higher than 1.
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