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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Diffuse scattering of lamellar optical gratings due to line edge roughness
 Schröder, S. ; Society of PhotoOptical Instrumentation Engineers SPIE, Bellingham/Wash.: Optical Fabrication, Testing, and Metrology VI : 1517 May 2018, Frankfurt, Germany Bellingham, WA: SPIE, 2018 (Proceedings of SPIE 10692) ISBN: 9781510619210 ISBN: 9781510619227 Paper 106920I, 9 pp. 
 Conference "Optical Fabrication, Testing, and Metrology" <6, 2018, Frankfurt> 

 English 
 Conference Paper 
 Fraunhofer IOF () 
Abstract
In recent years, the scattering properties of optical gratings became of high interest. In particular, the effect of line edge roughness (LER) in lamellar diffraction gratings was identified to be a potential source of stray light. In this contribution the LERinduced scattering spectrum of such gratings is investigated. The straightforward method to calculate the angle resolved scattering (ARS) is offered by twodimensional simulation tools, e.g. the rigorous coupled wave analysis (RCWA). Unfortunately, this approach suffers from computation times that typically lie in the range of several days. As a simplification, we apply a novel onedimensional rigorous approach1 that permits the prediction of ARS along the dispersion direction of the grating within a feasible computation time. As the 1Dmodel only accounts for the LERparameter σ and neglects the correlation length ξ and the roughness exponent α, analytical considerations must be employed in order to adapt the 1Dsimulation results to the 2Dreality.1 The model is verified by comparison to the 2Dmodel and ARSmeasurements of Ebeam exposed gratings with artificially induced (and strongly determined) LER. Based on the derived 1Dmodel, the effects of different parameters on the straylight performance of a high performance spectrometer grating is investigated. As a result we find that not only the roughness parameters but also the grating geometry has a significant effect especially on the spatial distribution of the scattered light. In other words, the strength of the scattered light next to the (spectrometric) useful diffraction order can be controlled by the grating geometry, too. Hence, the presented algorithm might be a useful tool for designing gratings with strong straylight specifications.