Fig. 1: Design of dual chiral framework.

a, b Functional design for dynamic optical chirality. A helix structure (a) can be stretched and contracted to alter its chiroptical response. If one wants to completely reverse the structure from left-handed (LH) to right-handed (RH), the system needs to overcome a giant energy barrier. For a dual chiral framework (b), dynamic modulation between positive and negative values can be achieved by matching the zero points of their helicity (H). c Schematic of the framework made by nano-cilia metasurface integrated with thermoresponsive cholesteric liquid crystal (LC). The dual chiral structures enable the amplification, elimination, and reversal of chiroptical response at different temperatures. d Electric field distributions of RH-cilia. The RH-cilia exhibits stronger plasmonic resonance to LCP, resulting in lower transmittance of LCP compared to RCP. e Schematic of the chiral transmission of LC versus temperature at fixed wavelength (λ). The thermoresponsive LC pitch (P) will shrink after being heated, leading to a blueshift of the CPL photonic bandgap and the subsequent change in transmission. When the bandgap shifts, the transmission initially decreases, reaches and maintains a minimum, and finally increases. The gray background marks the “ON” state of the LC. f, g Illustration of different combinations of two chiral elements to obtain a tunable and dual chiral framework. In (f) the nano-cilia and LC with opposite chiroptical response (+CD and −CD) enables the elimination and reversal of CD. In comparison, in (g) nano-cilia and LC with both positive chiroptical response (+CD and +CD) can achieve the amplification of CD.