Strain-enhanced dynamic regulation of chiroptical responses in 3D suspended nested metamaterials

Three-dimensional (3D) chiral metamaterials, which exhibit strong chiroptical responses, have attracted tremendous attention in the broad fields of next-generation photonic devices and chiroptical spectroscopy techniques. There is an urgent need for a novel fabrication approach that enables the rapid and straightforward preparation of 3D chiral nanostructures, along with a robust strategy for achieving dynamic regulation. Here, we proposed a strain-enhanced strategy for dynamically regulating the chiroptical responses of 3D suspended nested metamaterials from the transformation of a 2D precursor. The local strain enhancement could effectively resolve the bottleneck of insufficient strain and low precision for the buckling strain self-assembly. The changing morphology and circular dichroism (CD) of 3D suspended chiral metamaterials were analyzed under the impact of a strain-enhanced effect. Then, the uplifted heights of these 3D nanostructures increased with the substrate's pre-strain (<i>ɛ_pre</i>). Its CD reached up to 0.79, mainly resulting from ring electric dipoles. Interestingly, the chiroptical responses of 3D nanopyramids were regulated dynamically by controlling the substrate's pre-strain. Such a strategy provides a new pathway for achieving high-performance chiral metamaterials and offers promising applications in circularly polarized light detection, super-chiral light sources, optical communication, and advanced nanophotonic systems.