Patent ID: 9575324
Date: 2017-02-21
CPC Classifications: G02B,G21K,H05G

Claim:
1. A beam guiding apparatus, comprising: a vacuum chamber comprising a target region arranged to receive a target material for generating EUV radiation, wherein the vacuum chamber further comprises a first opening for receiving into the vacuum chamber a first laser beam and a second opening for receiving into the vacuum chamber a second laser beam; a superposition apparatus arranged to superpose the first laser beam having a first wavelength and a second laser beam having a second wavelength for common beam guidance in the direction of the target region; and a beam shaping apparatus arranged upstream of the superposition apparatus in the beam path of the second laser beam, wherein the beam shaping apparatus is configured to set a ring-shaped beam profile of the second laser beam, wherein the first laser beam and the second laser beam have different wavelengths, wherein the superposition apparatus comprises a reflecting optical element, arranged in the vacuum chamber, the reflecting optical element comprising a) a first surface region for reflecting the first laser beam and b) a second surface region, surrounding the first surface region in a ring-shaped manner, for reflecting the second laser beam, and wherein the reflecting optical element is configured to expand the first and second laser beams.