Switching chirality in arrays of shape-reconfigurable spindle microparticles.

Giant circular photo-galvanic effect has been realized in chiral metals when illuminated by the circularly polarized light. However, the structure itself is not switchable nor is the crystal chirality in the adjacent chiral domains. Here w e synthesize spindle-shaped liquid crystalline elastomer (LCE) microparticles that can switch from prolate to spherical to oblate reversibly upon heating above the nematic to isotropic transition temperature. When arranged in a honeycomb lattice, the continuous shape change of the microparticles leads to lattice reconfiguration, from a right-handed chiral state to achiral one, then to a left-handed chiral state, without breaking the translational symmetry. Accordingly, the sign of rotation of the polarized light passing through the lattices changes as measured by time-domain terahertz (THz) spectroscopy. Further, w e can locally alter the chirality in the adjacent domains using near-infrared (NIR) light illumination. The reconfigurable chiral microarrays will allow us to explore non-trivial symmetry protected transport modes of topological lattices at the light-matter interface. Specifically, the ability to controllably create chiral states at the boundary of the achiral/chiral domains will lead to rich structures emerging from the interplay of symmetry and topology. This article is protected by copyright. All rights reserved.