Nonlocal metasurface fabricated by quantum dot embedded resin printing

Abstract

A metasurface, an arrangement of sub-wavelength nanostructures, is a unique flat optic device that can perform a desired function such as shaping a polarization of light. The conventional metasurface, using the optical response of individual scatters, modulates the optical properties over a broad wavelength range. However, the nonlocal metasurface, using the interaction between neighbor nanostructures, can operate at a narrow wavelength band. Therefore, the nonlocal metasurface can perform an optical function wavelength-selectively. Nanoimprinting method can fabricate a metasurface using Titanium oxide (TiO2) particle-embedded resin. This method can replicate a metasurface in large quantities, overcoming the limit of the conventional nanofabrication process.

Here, we mix quantum dots (QDs) into the precursor resin, so that the QDs are uniformly embedded in the imprinted metasurface. When the metasurface behaves as both an emitter and a resonator concurrently, the portion of which photons from the QDs are coupled to the resonance mode increases. We design a nonlocal metasurface using the refractive index of QDs embedded composites (~1.9). This nonlocal metasurface supports polarization selective resonance mode at the QD’s emission wavelength. Despite the relatively low refractive index, the nonlocal metasurface theoretically supports high quality factor of about a few thousand. Therefore, this metasurface has two functionalities: photoluminescence enhancement and polarization selective emission. We expect that this device provides a promising way for a polarization-dependent light source, sensing, and display.