Diffractive shaping of excimer laser beams |
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| Authors: | J. Turunen P. Pääkkönen M. Kuittinen P. Laakkonen J. Simonen T. Kajava |
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| Affiliation: | 1. University of Joensuu, Department of Physics , P.O. Box 11 1, FIN-80101, Joensuu, Finland;2. elsinki University of Technology, Department of Engineering, Physics and Mathematics , P.O. Box 2200, FIN-02015, HUT, Espoo, Finland |
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| Abstract: | Abstract We address the problem of shaping the intensity distribution of a highly directional partially coherent field, such as an excimer laser beam, by means of diffractive optics. Our theoretical analysis is based on modelling the multi-transverse-mode laser beam as a Gaussian Schell-model beam. It is shown numerically that a periodic element, which is unsuitable for the shaping of a coherent laser beam, works well with an excimer laser beam because of its partial spatial coherence. The conversion of an approximately Gaussian excimer laser beam into a flat-top beam in the Fourier plane of a lens is demonstrated with a diffractive beam shaper fabricated as a multilevel profile in SiOl by electron-beam lithography and proportional reactive-ion etching. |
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