Tang Yutao, Deng Junhong, Li King Fai, Jin Mingke, Ng Jack, Li Guixin
Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Adv Mater. 2019 Jun;31(23):e1901188. doi: 10.1002/adma.201901188. Epub 2019 Apr 17.
Photonic metasurfaces, a kind of 2D structured medium, represent a novel platform to manipulate the propagation of light at subwavelength scale. In linear optical regime, many interesting topics such as planar meta-lenses, metasurface optical holography, and so on have been widely investigated. Recently, metasurfaces have gone into the nonlinear optical regime. While it is recognized that the local symmetry of the meta-atoms plays a vital role in determining the polarization, phase, and intensity of the nonlinear waves, much less attention has been paid to the global symmetry of the nonlinear metasurfaces. According to the Penrose tiling and the newly proposed hexagonal quasicrystalline tiling, nonlinear optical quasicrystal metasurfaces are designed and fabricated based on the geometric-phase-controlled plasmonic meta-atoms with local rotational symmetry. It is found that the far-field radiation behavior of second harmonic generation waves are determined by both the tiling schemes of quasicrystal metasurfaces and the local symmetry of meta-atoms they consist of. The proposed concept may open new avenues for designing nonlinear optical sources with metasurface crystals.
光子超表面是一种二维结构化介质，是在亚波长尺度上操纵光传播的新型平台。在线性光学领域，诸如平面超透镜、超表面光学全息术等许多有趣的课题已得到广泛研究。近来，超表面已进入非线性光学领域。虽然人们认识到超原子的局部对称性在决定非线性波的偏振、相位和强度方面起着至关重要的作用，但对非线性超表面的全局对称性关注较少。根据彭罗斯镶嵌和新提出的六边形准晶镶嵌，基于具有局部旋转对称性的几何相位控制等离子体超原子设计并制造了非线性光学准晶超表面。研究发现，二次谐波产生波的远场辐射行为由准晶超表面的镶嵌方案及其所包含的超原子的局部对称性共同决定。所提出的概念可能为利用超表面晶体设计非线性光源开辟新途径。
