| 摘要 |
Apparatus for narrowing the bandwidth of a light beam. The invention relates to an apparatus for narrowing the bandwidth of a light beam for at least one frequency or wavelength which can be predetermined, having a diffraction grating (3) for the predetermined frequency or wavelength and having light beam guidance means (1, 2) in order to point an incident light beam (4) at the diffraction grating. According to the invention, the diffraction grating is formed from two or more grating elements for the predetermined frequency or wavelength, and/or the light beam guidance means are designed to split the light beam into two or more beam elements (4a, 4b) and to point them at the diffraction grating such that they at least partially overlap in the grating longitudinal direction, with the beam elements being offset in the grating transverse direction and/or being polarised differently and/or striking the diffraction grating at incidence angles which correspond to different diffraction orders, for bandwidth narrowing with respect to the same predetermined frequency or wavelength. Use, for example, in excimer lasers which emit UV radiation, for lithography systems for wafer structuring.
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