标题：Subdiffraction focusing lens based on quadrangular-frustum pyramid-shaped metasurface
作者机构：[Li, Huaixin ;Li, Huaixin ;Li, Huaixin ;Li, Huaixin ;Li, Huaixin ;Li, Huaixin ;Li, Huaixin ;Li, Huaixin ] Key Laboratory of Optoelectronic Technology 更多
摘要：In order to realize the function of subdiffraction focusing using a single flat lens, a special metalens is proposed to modulate the circularly polarized light. Initially, the analyses indicate that the phase shift can cover [0, 2π] by changing the rotation angle of a quadrangular-frustum pyramid-shaped structure from 0° to 180°, while the average amplitude transmittance can reach 96% at the wavelength of λ = 1550 nm. Then, a flat metalens is designed by carefully arranging the quadrangular-frustum pyramid-shaped structures. The simulated results show that a focal spot could be obtained at the focal length of about f = 2.87λ, and the focusing efficiency is ∼14.9%. Meanwhile, the full width at half maximum (FWHM) of the focusing spot is only 0.48λ, which is smaller than the diffraction limit. Furthermore, this designed metalens can function comparatively with a conventional lens in one-to-one imaging.
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