Quantum emitters-integrated flat optics using the guided mode-resonant metasurface and the hyperbolic metamaterial

Abstract

Solid-state quantum emitters are efficient, scalable single-photon sources with tunable properties of quantum yields and dipole oscillator strengths. Such emitters are emerging sources for a myriad of near-field light-matter interactions. The present-day conventional optics is being replaced by flat optics, which is outperforming and minimizing optics and photonics devices. A single metasurface made of nanoscatterers arranged in arrays can perform multiple tasks, like angle and polarization-dependent behaviours, directional beam steering, manipulation, selective scattering in reflection and transmission of electromagnetic fields, multifunctional operations, waveguiding, etc. In this thesis, we present our studies conducted on the near-field interaction of quantum emitters with two elements of flat optics, namely, the all-dielectric guided mode-resonant metasurface (GMR-MSR) and the plasmonic hyperbolic metamaterial (HMM). The theoretical descriptions of quantum emitters as the two-level system dipole sources and their near-field interactions with metasurfaces and metamaterials in terms of scattering Green’s functions have supported our experimental studies. In the first part of the thesis, the silver nanowire-HMM is studied to explore its cavity-like properties. We have derived its quality factors and confirmed the ultranarrow mode volume of the delocalized scattering fields of the metamaterial. We have conducted spectral studies in time and frequency domains, complemented by the analytical model of the density matrix master equations and the numerical simulations performed using the finite difference time domain (FDTD) method to obtain the results. Next, the plasmonic cavity damping parameters of the HMM are studied with temperature-dependent light-matter interactions, which provide a non-monotonic behaviour in the scattering response and its Purcell enhancements. This study reveals the interplay between the electron and phonon scatterings in the silver nanowire array of the HMM. Scattering Green’s function analyses of the system confirm the observed non-monotonicity from the theoretical model. In the second part, we studied the near-field light-matter interaction properties of the silicon nitride made GMR-MSR with dipole emitters. We conducted numerical studies on the novel MSR platform using the scattering theory modelled by the Green’s functions and the corresponding Fano interference between the mode continuum and the discrete modes generated by the MSR. We find the MSR system providing Purcell enhancements for the sharp, directional scattering outcoupling and waveguiding. It also reveals unprecedented results, like the observable resonance redshift and the resonance linewidth narrowing. Moreover, the study reveals that the GMR-MSR is capable of showing nonlocal scattering field responses along its plane. In the last part of the thesis, we present the interaction of the quantum well single-photon emitter with the GMR-MSR and study their spatiotemporally tunable partial coherence properties. It started with the description of the statistics of the excitons’ and biexcitons’ contribution in the single-photon emission of quantum wells. Then, we extended it to resonantly couple at the near field with the GMR-MSR. We observe a tunable, partially coherent single-photon emission property from the coupled system. Thus, the coupled system works as a steady source of single photons on chip. We have explained the tunability of the partial coherence properties, quantified them following the spatio-temporal coupled mode theory of the resonant metasurface, and discussed its potential applications as an efficient on-chip photonic device.