Ultrathin TiN Films Based Metasurface with Tunable Circular Dichroism in Near-Infrared Region

Tunable chiral metasurfaces, exhibiting giant chiroptical responses and flexible tunability, hold great promise for applications in polarization sensitive electro-optical information processing and biosensing. In this paper, we proposed a quasi -shaped chiral metasurface, which achieves continuously tunable circular dichroism (CD) by adding two ultrathin TiN film strips to the typical MIM structure, with a maximum CD of 0.63. After the bias voltage is applied to the TiN films, the carrier concentration will be changed, allowing the response peak of CD to be regulated between 1617 and 1707nm. The obvious CD effect and the ability of continuously tunability have broad application prospects in multifunctional optical devices.