US 12,300,959 B2
Optical assembly for reducing a spectral bandwidth of an output beam of a laser
Johannes Kraus, Theilheim (DE); Oliver Gloeckl, Aalen (DE); and Markus Deubel, Aalen (DE)
Assigned to Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed by Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed on Dec. 10, 2020, as Appl. No. 17/117,824.
Application 17/117,824 is a continuation of application No. PCT/EP2019/063857, filed on May 28, 2019.
Claims priority of application No. 102018209602.3 (DE), filed on Jun. 14, 2018.
Prior Publication US 2021/0098958 A1, Apr. 1, 2021
Int. Cl. H01S 3/0805 (2023.01); H01S 3/08 (2023.01); H01S 3/225 (2006.01)
CPC H01S 3/0805 (2013.01) [H01S 3/08009 (2013.01); H01S 3/08068 (2013.01); H01S 3/225 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An optical assembly, comprising:
a beam-expanding optical unit within a laser resonator, the beam-expanding optical unit configured to increase a beam cross section and reduce a divergence of a resonator-internal laser beam in an expansion cross-sectional dimension so that a resonator-internal expansion laser beam section arises;
an optical grating in a retroreflective arrangement for the resonator-internal laser beam;
a first beam-limiting stop in a beam path of the expansion laser beam section, the first beam-limiting stop configured to act in the expansion cross-sectional dimension; and
a second beam-limiting stop in a beam path of the resonator-internal laser beam on a side of the beam-expanding optical unit facing away from the grating,
wherein:
a width of the second beam-limiting stop is such that the first beam-limiting stop is overexposed by the resonator-internal laser beam and such that a width of a used beam cross section on the grating is defined by the first beam-limiting stop; and
an adjustment range of the beam-expanding optical unit and a width of an input aperture of the second beam-limiting stop are matched to one another so that the first beam-limiting stop is fully illuminated in a case of an expansion and the first beam-limiting stop is overexposed with an increasing expansion.