Mode-coupled emission from hBN flakes on metal-dielectric multilayers

??The development of reliable and integrated single-photon sources (SPS) represents a key milestone toward the implementation of quantum communications and information technologies. In this framework, point-like lattice defects in hexagonal boron nitride (hBN) flakes has recently attracted significant attention as a promising solid-state emitter platform; thanks to its room-temperature operation, high photostability, and compatibility with on-chip photonic architectures. The aim of this work is to investigate the coupling of defect-related emission in hBN flakes with optical modes sustained by engineered multilayer structures, specifically metal-dielectric multilayers supporting Tamm plasmons (TPs) and dielectric multilayers supporting Bloch surface waves (BSWs). ?? ??This activity involves theoretical modeling, clean room fabrication and experimental optical characterization. Rigorous Coupled-Wave Analysis (RCWA) simulations are employed to calculate the optical response of multilayered structures. Electron beam lithography has been performed to fabricate sub-wavelength diffraction gratings on top of the multilayers, to facilitate the coupling with BSW modes. Hexagonal boron nitride flakes, prepared via mechanical exfoliation, are transferred onto the photonic structures and then indented with a heated AFM tip, to create local emitters. Finally, optical characterizations involving photoluminescence and white-light spectral measurements in both direct and Fourier space are performed. ?? ??The integration of hBN emitters with Bloch surface wave platforms and Tamm Plasmon structures is explored as a potential route to achieve enhanced emission directionality and improved coupling efficiency. Although further optimization and characterization are required, the presented results demonstrate the feasibility of hybrid hBN–multilayer systems as a versatile platform for the implementation of integrated quantum photonic devices upon optical pumping.