Urade Yoshiro, Fukawa Kai, Miyamaru Fumiaki, Okimura Kunio, Nakanishi Toshihiro, Nakata Yosuke
Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan.
Department of Physics, Shinshu University, Nagano 390-8621, Japan.
Nanophotonics. 2022 Jan 11;11(9):2057-2064. doi: 10.1515/nanoph-2021-0671. eCollection 2022 Apr.
Dynamic inversion of the planar-chiral responses of a metasurface is experimentally demonstrated in the terahertz regime. To realize this inversion, the critical transition of the checkerboard-like metallic structures is used. Resonant structures with planar chirality and their complementary enantiomeric patterns are embedded in the checkerboard. Using vanadium dioxide as a variable resistance, the metasurface is implemented in the terahertz regime. The responses of the metasurface to circularly polarized waves are then characterized by terahertz time-domain spectroscopy. Further, the sign of the circular conversion dichroism, which is closely related to the handedness of the planar chirality of the metasurface, is observed to be inverted at 0.64 THz by varying the temperature. Such invertible planar-chiral responses can be applied practically to the handedness-invertible chiral mirrors.
在太赫兹波段通过实验证明了超表面平面手性响应的动态反转。为实现这种反转，使用了棋盘状金属结构的临界转变。具有平面手性的共振结构及其互补对映体图案被嵌入到棋盘中。利用二氧化钒作为可变电阻，在太赫兹波段实现了超表面。然后用太赫兹时域光谱对超表面对圆偏振波的响应进行了表征。此外，通过改变温度，观察到与超表面平面手性的旋向密切相关的圆转换二向色性的符号在0.64太赫兹处发生反转。这种可反转的平面手性响应可实际应用于旋向可反转的手性镜。
