Resonance Enhanced Strong Coupling In 2D TMDCs and Perovskite

Abstract

Light-matter interaction within a strong coupling regime has attracted much attention because of its potential applications in quantum manipulation, Bose−Einstein condensation, optical transistors, coherent emission or absorption, photovoltaics, ultrafast optical switching, sensing, low-threshold lasers, quantum fluid of light and all-optical logic devices. However, conventional materials used in strong coupling suffer from several challenges, as follows: low working temperature, small binding energy, low-quality factor and challenging fabrication. To overcome these limitations, transition metal dichalcogenides (TMDCs) and 2D lead halide perovskite materials are used to achieve a strong coupling regime between optical and polariton modes. This thesis initially reviews previous studies that used TMDCs or perovskite materials in a strong coupling regime. Owing to TMDCs’ optical properties, several studies reported the strong coupling between exciton and optical cavities. However, current structures face many challenges, including difficulties in fabrication and the associated cost increase. The strong coupling between exciton in TMDCs monolayer, plasmonic resonance in silver and anapole mode in Silicon nanodisk was analysed at room temperature and normal incident. This nanostructure provides large Rabi splitting accompanied by a giant field enhancement, thereby paving the way for the creation of exciton-polariton devices. Although previous studies used metallic nanocavities to excite plasmonic resonances that offered a small mode volume and strongly coupled them with exciton in TMDCs, damping losses in metals degraded the performance of exciton-polariton systems. Consequently, researchers used dielectric materials as an alternative to plasmonic materials to observe a strong coupling regime. However, exciton-polariton devices that use dielectric materials suffer from large mode volumes. This thesis explores the strong coupling between hybrid resonance and exciton in hybrid dielectric-metallic nanostructure and TMDC monolayer by using metallic and dielectric materials that include small mode volume low losses. Another material with potential for strong coupling is lead-halide perovskite. Lead halide perovskite materials have a larger binding energy at room temperature compared with conventional materials. Thus, the strong coupling between exciton of perovskite and photonic cavity has been demonstrated in different platforms, such as plasmonic nanocavity and distributed Bragg reflector-based microcavity. The former suffers from large intrinsic loss due to the nature of noble metals, and the latter may involve a complex fabrication process. In recent years, researchers have also used a guided-mode resonance supported by a photonic crystal slab to achieve exciton-polariton in perovskite metasurface. In this thesis, the strong coupling between Mie resonances and exciton is explored at room temperature without resorting to other photonic cavities. Finally, at the end of this thesis, the future perspective and a summary of this research's main results are presented.