Tuning the Chiroptical Properties of Elongated Nano-objects <i>via</i> Hierarchical Organization.

Abstract

Chiral materials appear as excellent candidates to control and manipulate the polarization of light in optical devices. In nanophotonics, the self-assembly of colloidal plasmonic nanoparticles gives rise to strong resonances in the visible range, and when such organizations are chiral, a strong chiroplasmonic effect can be observed. In the present work, we describe the optical properties of chiral artificial nanophotonic materials, <i>Goldhelices</i>, which are hierarchically organized by grazing incidence spraying. These <i>Goldhelices</i> are made by plasmonic nanoparticles (gold) grafted onto helical templates made from silica nanohelices. A comparison of oriented <i>versus</i> non-oriented surfaces has been performed by Mueller matrix polarimetry, showing the importance of the organization of the <i>Goldhelices</i> regarding their interaction with light. Moreover, mono- <i>versus</i> multilayer photonic films are created, and the measured optical properties are discussed and compared to simulations.