%0 Journal Article
%A Ginn, James
%A Alda, Javier
%A Gómez Pedrero, José Antonio
%A Boreman, Glenn
%T Monochromatic aberrations in resonant optical elements applied to a focusing multilevel reflectarray
%D 2010
%@ 1094-4087
%U https://hdl.handle.net/20.500.14352/44988
%X The monochromatic aberrations produced by the phase distribution reflected by resonant sub-wavelength metallic structures are studied both analytically and numerically. Even for normal incidence, the angular dependence of the re-radiated wavefront disturbs the overall performance of the reflectarray. This effect is modelled as combination of a linear and a cubic dependence. A complete numerical simulation of a multilevel focusing reflectarray is performed using computational-electromagnetic and physical-optics-propagation methods. A modified Strehl ratio is defined to show the dependence of the focused spot behavior on aperture. The irradiance distribution is dependent on the polarization state. A small-aperture focusing reflectarray has been designed, fabricated, and tested. The irradiance distribution at the focusing plane is compared with the simulated one, showing a good agreement when residual wavefront aberrations are included.
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