Coupling of Photon Emitters in Monolayer WS₂ with a Photonic Waveguide Based on Bound States in the Continuum

Abstract

On-chip light sources are an essential component of scalable photonic integrated circuits (PICs), and coupling between light sources and waveguides has attracted a great deal of attention. Photonic waveguides based on bound states in the continuum (BICs) allow optical confinement in a low-refractive-index waveguide on a high-refractive-index substrate and thus can be employed for constructing PICs. In this work, we experimentally demonstrated that the photoluminescence (PL) from a monolayer of tungsten sulfide (WS 2 ) could be coupled into a BIC waveguide on a lithiumniobate-on-insulator (LNOI) substrate. Using finite-difference time-domain simulations, we numerically obtained a coupling efficiency of ∼2.3% for an in-plane-oriented dipole and a near-zero loss at a wavelength of 620 nm. By breaking through the limits of 2D-material integration with conventional photonic architectures, our work offers a new perspective for light−matter coupling in monolithic PICs.

Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

“…These states have been observed in various wave contexts, including electromagnetic waves 55 , acoustic waves and elastic waves in solids 58 . They have been also studied in diverse material systems such as photonic crystals 59 , optical waveguides 60 , quantum dots 61 , and topological insulators 62 . Recent developments in metasurface have led to the creation of multiple papers such as ultrasensitive dual-band terahertz metasurface sensors based on all-InSb resonators, investigation of ultrahigh-Q factor TD resonances at terahertz frequencies arising from a distortion of symmetry-protected BIC in the metasurface 63 , nanoscale refractive index sensor with ultrahigh figure of merit based on toroidal dielectric metasurfaces which presents a novel approach to refractive index sensing using a dielectric metasurface with two semicircle disks clusters 1 , and …, where high sensitivity and selectivity for specific frequency bands were achieved.…”

Dynamic Strain Modulation of a Nanowire Quantum Dot Compatible with a Thin-Film Lithium Niobate Photonic Platform

“…Quantum computation with on-chip photonic qubits has emerged as an important research area in quantum technologies. − In addition to the manipulation and detection of individual photons, achieving deterministic integration of single and indistinguishable photon sources is essential for the scalability and complexity of quantum photonic circuits. − Although more technologically challenging than monolithic approaches, − the heterogeneous integration of high-quality quantum emitters offers the possibility of producing more efficient devices and incorporating additional functionalities that would be difficult to achieve in single material systems. Toward this direction, III/V semiconductor quantum dots (QDs), − and defects in crystals , or in 2D materials − have been successfully transferred to Si, SiN, AlN, or LiNbO 3 while maintaining good performances as single photon sources. In addition to their individual properties, multiple sources integrated on the same chip must be spectrally identical if indistinguishable photons are to be generated for linear quantum operations .…”