Multifunctional Metamirror: Polarization Splitting and Focusing

Abstract

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×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. 1 arXiv:1709.04257v2 [cond-mat.mes-hall]

Progresses in the practical metasurface for holography and lens

“…Unlike the PB phase-based metalens, the metalens operates independently of the polarization because the phase is adjusted according to the size of each meta-atom. Like the way that metahologram progresses, the metalens has also been developed to have multifunctionality as well [118][119][120][121][122][123]. For instance, the metamirror has been proposed to focus light with respect to linear polarization by plasmonic metamirror [118].…”

Phase Manipulation of Electromagnetic Waves with Metasurfaces and Its Applications in Nanophotonics

“…[222] Copyright 2016, American Association for the Advancement of Science. [240] Copyright 2017, American Chemical Society. Reproduced with permission.…”

“…To further enhance the information capacity, a 3D volumetric vortex array with independently controllable topological charges of a sequence of coaxial beam profiles in the longitudinal propagation direction that can be present for the 2D diffraction orders in each transverse plane was recently explored, as illustrated in Figure 9g. [240] Bifunctional metadevices composed of anisotropic unit cells with polarization-dependent transmission and reflection phase responses to efficiently manipulate EM waves in the full space in the microwave regime were recently proposed, as illustrated in Figure 9i. [238] As a multiplexer, beams without OAM can be transferred into coaxial beams carrying various OAM features using various incident angles; as a demultiplexer, coaxial beams carrying multi-OAMs can be divided into various directions with fundamental modes.…”

“…Reproduced with permission. [240] Copyright 2017, American Chemical Society. i) Schematic illustration of the polarization-dependent full-space bifunctional metadevices.…”

“…[239] Polarization-controlled optical metadevices have been developed based on harmonic-response metasurfaces as well, such as a polarization splitting and focusing metamirror that can simultaneously split orthogonal light polarizations and focus them into different focal spots, as shown in Figure 9h. [240] Bifunctional metadevices composed of anisotropic unit cells with polarization-dependent transmission and reflection phase responses to efficiently manipulate EM waves in the full space in the microwave regime were recently proposed, as illustrated in Figure 9i. [241,242] Relying on different optimization methods, the harmonic response concept can also be implemented in multi-image metaholograms, as we discussed in Section 4.1.…”