Patent ID: 9647406
Date: 2017-05-09
CPC Classifications: H01S,H05G

Claim:
1. A laser unit, comprising: a master oscillator configured to output a laser light beam; a laser amplifier disposed in a light path of the laser light beam outputted from the master oscillator; an adjuster disposed in the light path of the laser light beam, and configured to adjust a beam cross-sectional shape of the laser light beam amplified by the laser amplifier to be a substantially circular shape, the beam cross-sectional shape being at a beam waist of the laser light beam or in the vicinity of the beam waist of the laser light beam, and being in a plane orthogonal to a light path axis; a detecting section disposed at a downstream of the adjuster in the light path of the laser light beam, and configured to detect the beam cross-sectional shape at the beam waist or in the vicinity of the beam waist; and a controller configured to control the adjuster, based on a result of the detection by the detecting section, wherein the adjuster includes a movable optical member and a rotary mechanism, the movable optical member being configured to vary a beam diameter of the laser light beam in one direction that is orthogonal to the light path axis, the rotary mechanism being configured to rotate the movable optical member around the light path axis of the laser light beam, the controller measures, based on the result of the detection by the detecting section, a first direction in which the beam diameter is maximized in the plane orthogonal to the light path axis and a second direction in which the beam diameter is minimized in the plane orthogonal to the light path axis, and the controller controls the rotary mechanism to allow the direction in which the beam diameter of the laser light beam is varied by the adjuster to be substantially the same as one of the first direction and the second direction.