Nano-photonic control of light-matter interactions in two-dimensional materials

Abstract

Excitons in two-dimensional semiconductor have been focused by their fabulous material properties such as bosonic nature, strong binding energy, high internal quantum efficiency, and spin-valley locking. To exploit the excitons as a platform for quantum many-body phenomena and optoelectronic devices, their lifetime have to be tailored without perturbation on their material properties. Nanophotonic manipulation of the local density of optical state can pave a way to control the radiative decay rate and the optical excitation of exciton. Here, I present three type of nanophotonic platforms for utilizing two-dimensional excitons’ decay dynamics. Additionally, I present the theoretical study of the canonical spin angular momentum distribution nearby a nanophotonic structure. First, I suggest the plasmonic photonic crystal mirror for long-lived interlayer exciton generation. With employing the numerical simulations, I reveal that the radiative decay rate of the out-of-polarized dipole emitter, which corresponds to an interlayer exciton, can be prohibited with the band gap of the plasmonic photonic crystal mirror. Second, I present the plasmonic metasurfaces for optical customization of the decay dynamics of excitons in a two-dimensional semiconductor. The metasurfaces experimentally manipulated the radiative decay rate of excitons in MoSe2 monolayer depending on the position by two orders of magnitude. Also, I demonstrated the polarization dependent exciton radiative decay using an anisotropic metasurface. Third, I present the spatial modulation of radiative decay dynamics of exciton complexes in the WSe2 monolayer employing a gradient-thickness mirror. I demonstrated that the spatially varying ratio between the photoluminescence intensity from the exciton complexes. Finally, I present a theoretical study on three-dimensional textures of the canonical spin angular momentum distribution of a sub-wavelength plasmonic nanostructure and nanoscale engineering of their behaviors.