Photoinduced handedness switching in terahertzchiral metamolecules

摘要

Switching the handedness, or the chirality, of a molecule is of great importance in chemistryand biology, as molecules of different handedness exhibit dramatically different physiologicalproperties and pharmacological effects. Here we experimentally demonstrate handednessswitching in metamaterials, a new class of custom-designed composites with deepsubwavelength building blocks, in response to external optical stimuli. The metamoleculemonolayer flips the ellipticity and rotates the polarization angle of light in excess of 10° underoptical excitation, a much stronger electromagnetic effect than that of naturally availablemolecules. Furthermore, the experimentally demonstrated optical switching effect doesnot require a structural reconfiguration, which is typically involved in molecular chiralityswitching and is inherently slow. The handedness switching in chiral metamolecules allowselectromagnetic control of the polarization of light and will find important applications inmanipulation of terahertz waves, such as dynamically tunable terahertz circular polarizers andpolarization modulators for terahertz radiations.