Tunable Chirality by Stacking Films of Magnetically Assembled Plasmonic Nanochains.

Precise and dynamic control over chiroptical properties is highly desirable for applications that demand tunability and programmability. However, conventional templating strategies for chiral nanostructures often offer limited flexibility in modulating chiroptical responses, largely due to the inherent rigidity of the templates. In this work, a simple and highly adaptable approach is introduced for constructing plasmonic chiral architectures via the twisted stacking of polymer films embedded with magnetically aligned chains of plasmonic nanoparticles. The intrinsic one-dimensional anisotropy of these nanochains, together with geometric control over interlayer orientation, allows continuous tuning of circular dichroism characteristics, including spectral position, intensity, and handedness. In addition, plasmonic resonances in the visible range give rise to tunable colors from optical rotatory dispersion. The generality of this approach is further illustrated by hetero-structured stacking and multilayer assemblies, which provide expanded control over chiroptical behavior. Overall, this strategy offers a versatile platform for designing reconfigurable chiral optical materials with potential applications in sensing, photonic devices, and information encoding.