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(458a) Light-Induced Chiral Metamaterial Printing

McGlothin, C., University of Michigan
Turali-Emre, E. S., University of Michigan
Choi, W., University of Michigan
Kotov, N., University of Michigan
Imposing chiral bias during the synthesis of individual nanoparticles (NPs) and their assemblies enables to generate various 3D metamaterials with structural complexity. The chiral inorganic nanostructures with axial geometries aligned perpendicularly to the substrates are particularly the best for applications in meta-optics. However, due to the high thermodynamic penalties for out-of-plane alignment of nanocolloids, such geometry on surface/interface through self-assembly hitherto remains virtually unexplored. Therefore, most of manufacturing chiral inorganic superstructure on substrates now rely on the high-cost and time-consuming fabrication methods, which require either multistep lithography or depositions by instrumentation with high temperatures and/or low pressures. Here, we show that the strong optical activity of plasmonic materials under circularly polarized light (CPL) afford photon to matter chirality transfer, fabricating silver nanohelicoids (AgNH) on arbitrary substrates over the centimeter scale area in minutes. Illuminating CPL on substrate immersed in silver salt solutions induces the formation of NPs with 15–20 nm in diameter and their subsequent asymmetric deposition/assemblies. The handedness of the AgNH is altered from left to right when circular polarization of the incident photons changed from right to left, showing opposite polarity in their circular dichroism (CD) spectra. The wavelength of light source determined the size of the final superstructure as well as their CD band wavelength. Such dependence opens the path to printed metamaterials with ‘on-the-fly’ control of polarization rotation, showing tunability of their chiroptical activities in spectral range from UV to near infrared. These simple and versatile architected metamaterials can be used for extensive applications, including but not limited to photonic, optoelectronic, and electromechanical devices as well as enantioselective catalytic and sensing systems.