Yoshito Tanaka and Shun Hashiyada (Hokkaido University) and Malcolm Kadodwala (University of Glasgow) have proposed a real-time, all-optical method for modulating optical activity in plasmonic chiral nanostructures using structured light without altering the nanostructure geometry. By using optical vortex beams with spin and orbital angular momentum, they achieve dynamic control of the dichroism through selective excitation of optically dark multipolar modes. This technology, which is independent of thermal, mechanical, and chemical stimuli, opens up new possibilities for high-speed, high-efficiency nanophotonics applications.

https://pubs.acs.org/doi/10.1021/acs.nanolett.5c03044/