Nanostructured materials for circular dichroism and chirality at the nanoscale: towards unconventional characterization [Invited]

In this work, we review the last attempts to use nanostructured materials for the enhancement of the chiro-optical effects at the nanoscale. Starting from the numerical design, we review different geometries that exhibit circular dichroic behavior in the far field; we then focus on the new branch of near-field chirality, where numerous nanostructures have been proposed for background-free chiral sensing. The next section reports on nanofabrication methods, with a special focus on self-assembling, cost- and time-efficient techniques. Finally, we review the chiro-optical experiments. Besides conventional extinction-based techniques, we are today able to reveal chiro-optical effects via photothermal behavior and photoluminescence, going down to single nanostructure chirality with sophisticated near-field techniques. We believe that the novel designs, state-of-the-art nanofabrication and modern characterization techniques have come to a stage to provide chiro-optical sensors and light components based on nanostructures.