Optical Self-Assembly of Chiral Nanostructures by a Seed Symmetry-Breaking Effect

Abstract

It has been established that assembling chiral nanostructures using a circularly polarized laser is formidable due to their symmetry mismatch. Traditionally, complex light fields or chiral precursors are considered prerequisites for optical chiral self-assembly. Herein, an unexpected seed symmetry-breaking (SSB) effect is reported, through which not only are chiral structures readily assembled by circularly polarized light in a controllable manner, but the physical mechanism of chiral assembly reported so far is also clarified. The SSB effect refers to a phenomenon of symmetry reduction in photo-generated structures—the seed for ensuing structure growth—which inevitably leads to a chiral near field and the formation of resultant chiral structures. As proof of concept, the near fields as well as the process of chiral structure evolution are recorded using a low-melting-point film. In this particular case, laser-induced nanoscale Rayleigh–Taylor instability (nano-RTI) is responsible for the initial SSB. Consequently, a simple and rapid chiral structure self-assembly method is developed, and a programmable array with a 15% peak in the circular differential scattering spectrum (CDS) is realized.