Photocontrollable Chiral Switching and Selection in Self-Assembled Plasmonic Nanostructure

Reversible photocontrol of dynamic chirality in self-assembly systems is of great importance in exploitations of artificial nanomachines for scientific and industrious applications. Here, a new strategy is proposed for achieving optically chiral controls based on photoswitchable plasmonic nanostructures. Chiral plasmonic nanoassemblies that are responsive to optomechanical perturbations exerted by circular polarized light (CPL) in the visible (vis)/near infrared (NIR) region are designed. The reversible photoswitching between opposite chiral states is verified by circular dichroism (CD) spectral signals. Theoretical simulations reveal the key role of optical torques in driving this chiral switching. By regulating light polarization or tuning light frequency to excite different plasmonic modes of the nanostructures, such an optomechanically driven chiral switching can enable a directed mirror-symmetry breaking and selective chiral amplification in nanoassemblies. This plasmon-based photoswitching nanosystem can operate at the optical transparent window, showing particular advantages over most of the molecular photoswitches for applications in living systems.