Metasurfaces are paving the way to improve traditional optical components by
integrating multiple functionalities into one optically flat metasurface
design. We demonstrate the implementation of a multifunctional gap surface
plasmon-based metasurface which, in reflection mode, splits orthogonal linear
light polarizations and focuses into different focal spots. The fabricated
configuration consists of 50 nm thick gold nanobricks with different lateral
dimensions, organized in an array of 240 nm x 240 nm unit cells on the top of a
50 nm thick silicon dioxide layer, which is deposited on an optically thick
reflecting gold substrate. Our device features high efficiency (up to ~65%) and
polarization extinction ratio (up to ~30 dB), exhibiting broadband response in
the near-infrared band (750-950 nm wavelength) with the focal length dependent
on the wavelength of incident light. The proposed optical component can be
forthrightly integrated into photonic circuits or fiber optic devices.Comment: 18 pages, including 5 figure