Chiral plasmonic DNA nanostructures with switchable circular dichroism

• DOI: 10.1038/ncomms3948
• Publication Date: 2013-12-13T11:15:32Z
• Authors: Robert Schreiber; Ngoc Luong; Zhiyuan Fan; Anton Kuzyk; Philipp C. Nickels; Tao Zhang; David M. Smith; Bernard Yurke; Wan Kuang; Alexander O. Govorov; Tim Liedl
• Keywords: Optics and Photonics; Surface Properties; optical physics; DNA, Single-Stranded; Metal Nanoparticles; 530; 01 natural sciences; Article; Nanocomposites; physical sciences; Materials Testing; Nanotechnology; Particle Size; nanotechnology; Circular Dichroism; Signal Processing, Computer-Assisted; Stereoisomerism; DNA; Electrical and Computer Engineering; 540; BRC; 0104 chemical sciences; Solutions; Glass; Gold

Circular dichroism spectra of naturally occurring molecules and also of synthetic chiral arrangements of plasmonic particles often exhibit characteristic bisignate shapes. Such spectra consist of peaks next to dips (or vice versa) and result from the superposition of signals originating from many individual chiral objects oriented randomly in solution. Here we show that by first aligning and then toggling the orientation of DNA-origami-scaffolded nanoparticle helices attached to a substrate, we are able to reversibly switch the optical response between two distinct circular dichroism spectra corresponding to either perpendicular or parallel helix orientation with respect to the light beam. The observed directional circular dichroism of our switchable plasmonic material is in good agreement with predictions based on dipole approximation theory. Such dynamic metamaterials introduce functionality into soft matter-based optical devices and may enable novel data storage schemes or signal modulators.