Random-phase metasurfaces at optical wavelengths.
Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector.
SDU Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Anders
A
Pors
SDU Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Fei
F
Ding
SDU Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Yiting
Y
Chen
SDU Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.|Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Ilya P
IP
Radko
SDU Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Sergey I
SI
Bozhevolnyi