Figure 1. Working principle of the polychromatic full-polarization metasurface. (IMAGE)
Caption
a. A typical scenario in which complex targets with different spectral and polarization information in low-illumination background need to be distinguished by airborne or spaceborne payloads. b. In traditional works based on geometric phase control, different rotation angles θ of the metaatoms represent different eigen-polarization states (EPS). In the Poincaré sphere, EPS is denoted by the precession axis OQ. The arcs in Poincaré sphere indicate polarization conversion paths and their lengths L determine the phase shifts φL. c. Schematic of a wavelength-decoupled coherent pixel. The architecture consists of four ordinary metaatoms with adjustable dimensions and orientations. With this configuration, untraditional phase responses at different wavelengths can be simultaneously and independently harnessed, thus enabling desired functionalities on any designated polarization state channels. The common geometric parameters of the metaatoms are: height 6 μm, period 1.55 μm. The supercell period is 3.1 μm. d. Schematic of a representative metadevice which achromatically focuses the incident light at three discrete wavelengths (3, 3.6 and 4.5 μm)-each assigned with a pair of arbitrarily chosen orthogonal polarizations- onto two opposite vertices of the hexagon.
Credit
by Jin Chen, Feilong Yu, Xingsi Liu, Yanjun Bao, Rongsheng Chen, Zengyue Zhao, Jiuxu Wan, Xiuxia Wang, Wen Liu, Yuzhi Sh, Cheng-Wei Qiu, Xiaoshuang Chen, Wei Lu, and Guanhai Li
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