Metasurfaces with tunable/switchable circular dichroism (CD) response have great potential to serve as important elements for plenty of advanced applications. In this work, we proposed a novel metasurface absorber integrated with periodic ${{\rm Ge}_2}{{\rm Sb}_2}{{\rm Te}_5}$ (GST) resonators and numerically demonstrated its capability in reconfiguration of the CD effect. Due to the strong chiral plasmonic resonance, a strong CD of about 0.75 can be achieved in a prescribed spectrum. Additionally, the phase transition of GST resonators enables the quasi-linearly modification of CD strength in a broad range (from 0.03 to 0.75). Furthermore, reversible chirality of the metasurface absorber can be realized by controlling the states of the left- and right-hand GST resonators separately, enabling the CD signal to be readily switched between on-, off-, and reverse-state.

中文翻译：

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具有可变和可切换的圆二色性的相变超表面

具有可调谐/可切换圆二色性（CD）响应的超颖表面具有巨大的潜力，可以用作许多高级应用程序的重要元素。在这项工作中，我们提出了一种新颖的超表面吸收剂，该吸收剂与周期性的$ {{\ rm Ge} _2} {{\ rm Sb} _2} {{\ rm Te} _5} $集成在一起（GST）谐振器，并在数值上证明了其重新配置CD效果的能力。由于强的手性等离子体共振，在规定的光谱中可以实现约0.75的强CD。此外，GST谐振器的相变使得CD强度可以在大范围（0.03至0.75）范围内进行准线性变化。此外，可以通过分别控制左侧和右侧GST谐振器的状态来实现超表面吸收器的可逆手性，使CD信号可以在开，关和反转状态之间轻松切换。