Tunable and Reconfigurable Dual-Band Chiral Metamirror

Chiral metasurfaces have recently undergone a dramatic development, due to their important applications in optics, chemistry and biology. However, the tunability and reconfigurability of the chiral metasurfaces remain challenges. Then, we proposed an S-shaped metamirror consisting of a MIM (Au-LiNbO
₃
-Au) structure with a dual-band chiral absorption in the near-infrared range. The proposed structure has two resonant wavelengths with a giant chiro-optical effect. The giant chiro-optical effect originates from the different plasmonic resonances induced by the incident circularly polarized light (CPL) with opposite spin states. By tuning the voltage and thus tuning the refractive index of the lithium niobate (LiNbO
₃
), chiral resonant wavelengths can be dynamically adjusted in a large range as desired. Furthermore, by tuning the refractive index of LiNbO
₃
, we can move the short-wavelength resonance peak to the position of another long-wavelength resonance peak. Therefore, the chiral metamirror can be dynamically reconfigured at the position of the long-wavelength resonance peak. The work offers a further step in developing tunable and reconfigurable chirality for possible applications including reconfigurable chiral hologram, chiral-selective absorber and other chiral components in near-infrared region.