Optical cavities coupled to 2D materials: Wavevector and Polarization Studies

Abstract

Controlling and manipulating light-matter interaction is one of the major goals of nanophotonics. Studying the interaction of light with materials has wide implications, including the development of sensors, photodetectors, phototransistors, LED, lasers, and other devices. After the discovery of graphene, two dimensional emerges as a major field of research as it possesses unique optical, mechanical, electrical, and chemical properties. TMDs are a special class of material as they are direct band semiconductors with high exciton binding energy. Their bandgap lies in visible to near-infrared wavelength range, and they shows high oscillator strength and valley selective optical properties. Engineering optical emission from two-dimensional transition metal dichalcogenides (TMDs) materials is important for creating and understanding nanophotonic devices based on two-dimensional materials. To achieve control over the emission properties of TMDs, one has to achieve control over parameter of the emitted light like intensity, polarization, and wavevectors. One of the approaches to control and manipulate these parameters is to place these materials inside the cavity. Coupling TMDs materials to optical cavities results in enhanced quantum yield of excitonic emission and can provide control over other emission properties enabling advanced quantum optics and nanophotonics devices. Herein, we discuss the effect of different metal film-based cavities on the wavevector and polarization of the emission from TMDs. We probed various metal-dielectric and metal-metal cavities using Fourier plane microscopy and spectroscopy. First, we have studied the wavevector and polarisation states TMDs sandwiched inside silver nanowire on mirror cavity and achieve the directional emission. Next, we have used the bent plasmonic nanowire on mirror cavity to further reduce the angular spread and reduce the back-reflected light. Finally, we discussed the effect of placing TMDs inside the microsphere on mirror. We have achieved beaming of TMDs photoluminescence using this cavity.