Tailored and broadband enhanced light chirality with dielectric metamaterials

Recently, several nanostructures with subwavelength scale dimensions were demonstrated to efficiently enhance light chirality. However, the intrinsic lossy nature of metals and inherent narrowband response of dielectric nanostructures pose severe limitations toward the practical realization of chiroptical systems. In our talk, we demonstrate a new way to tackle these problems by designing and experimentally realizing all-dielectric silicon-based L-shaped optical metamaterials based on tilted nanopillars that exhibit broadband and enhanced chirality in transmission operation. We use an emerging bottom-up fabrication approach, named glancing angle deposition, to assemble these new dielectric metamaterials on a wafer scale. We experimentally measure the strong and tunable chiral responses and theoretically explain our findings. The reported strong chirality can be tailored in terms of both amplitude and operating frequency. It may also be totally switched by simply varying the shape and dimensions of the nanopillars.