公开(公告)号：US20190334311A1

公开(公告)日：2019-10-31

申请号：US16507075

申请日：2019-07-10

Applicant: Gigaphoton Inc.

Inventor： Hiroaki HAMANO

IPC: H01S3/23 ,  H01S3/097 ,  B23K26/03 ,  B23K26/062 ,  B23K26/064 ,  B23K26/06

Abstract: A laser apparatus includes: a master oscillator for emitting a laser beam; an amplifier on an optical path of the laser beam; a beam splitter between the master oscillator and the amplifier for separating, from the optical path of the laser beam, at least part of a return beam traveling through the optical path of the laser beam in a direction opposite to a traveling direction of the laser beam; a focusing optical system for focusing the return beam separated from the optical path; and an optical sensor having a light receiving surface for the return beam for detecting information on power of the return beam entering the light receiving surface through the focusing optical system, the light receiving surface being arranged at a position different from a focusing position of the focusing optical system on the optical path of the return beam.