Far field diffraction of gratings with two roughness levels



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Torcal Milla, Francisco José and Sánchez Brea, Luis Miguel (2019) Far field diffraction of gratings with two roughness levels. Journal of optics, 21 (8). ISSN 2040-8978

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Official URL: http://dx.doi.org/10.1088/2040-8986/ab2bdf


We investigate the far field diffraction process produced by diffraction gratings with two roughness levels, such as steel tape gratings, which are used in environments where diffraction gratings made of glass are not possible. We obtain the analytical formulation describing the formation of diffraction orders in terms of the roughness parameters. Since roughness is stochastic, we use the mutual coherence function to propagate the field to the Fraunhofer regime. We conclude that diffraction orders exists when at least one correlation length of both roughness is larger than the period of the grating and the standard deviation on heights is around or larger than the illumination wavelength. Finally, we corroborate the analytical results with numerical simulations based on the fast Fourier transform, showing a high agreement.

Item Type:Article
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© 2019 IOP Publishing Ltd.
This work has been performed with the funding of Gobierno de Aragon-Fondo Social Europeo (Grupo de Tecnologia Optica Laser-E44_17R) and Ministerio de Economia y Competitividad (MINECO) 'Ecograb' of 'Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad' (DPI2016-75272-R); co-financed with structural funds of the European Union.

Uncontrolled Keywords:Diffraction; Diffraction gratings; Roughness; Far-field
Subjects:Sciences > Physics > Optics
ID Code:57015
Deposited On:26 Sep 2019 18:28
Last Modified:05 Jul 2020 23:01

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