Cavity-Enhanced 2D Material Quantum Emitters Deterministically Integrated with Silicon Nitride Microresonators

Abstract

Optically active defects in 2D materials, such as hexagonal boron nitride (hBN) and transition-metal dichalcogenides (TMDs), are an attractive class of single-photon emitters with high brightness, operation up to room temperature, site-specific engineering of emitter arrays with strain and irradiation techniques, and tunability with external electric fields. In this work, we demonstrate a novel approach to precisely align and embed hBN and TMDs within background-free silicon nitride microring resonators. Through the Purcell effect, high-purity hBN emitters exhibit a cavity-enhanced spectral coupling efficiency of up to 46% at room temperature, exceeding the theoretical limit (up to 40%) for cavity-free waveguideemitter coupling and demonstrating nearly a 1 order of magnitude improvement over previous work. The devices are fabricated with a CMOS-compatible process and exhibit no degradation of the 2D material optical properties, robustness to thermal annealing, and 100 nm positioning accuracy of quantum emitters within singlemode waveguides, opening a path for scalable quantum photonic chips with on-demand single-photon sources.

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field

“…A monolithic approach can also be applied to waveguides, with the QEs placed in the middle of the structure and the collection taking place from the two side grating couplers [221]. A striking 46% coupling efficiency was obtained with a waveguide coupled to a microring resonator made from Si 3 N 4 , with the coupling being deterministic, since the silicon nitride structure is grown after the identification of the emitter's position and of its dipole alignment [222] (a process that is shown in figures 5(f)-(h)).…”

Exciton–Photon Interactions in Two-Dimensional Semiconductor Microcavities

“…Recently, the emitter-like narrow emission bands in monolayer WS 2 disks prepared by such a strategy have been observed, in which the defect-related localized excitons play a key role. 158 The following step will be the coupling of microcavity-enhanced single-photon emitters with the on-chip waveguides and other functional photonic elements in integrated photonic circuits to verify the technological feasibility, where the waveguides can be made by silicon-based materials 159 or planar photonic crystal membranes. 160 Recently, with the silicon-nitride (SiN) microring resonators, the single-photon emission from 2D materials has been efficiently coupled into the SiN waveguide, 159 in which the bandgaps of prevailing 2D semiconductors are suitable to the transmission window of the SiN, i.e., from UV to telecommunication wavelengths.…”

“…158 The following step will be the coupling of microcavity-enhanced single-photon emitters with the on-chip waveguides and other functional photonic elements in integrated photonic circuits to verify the technological feasibility, where the waveguides can be made by silicon-based materials 159 or planar photonic crystal membranes. 160 Recently, with the silicon-nitride (SiN) microring resonators, the single-photon emission from 2D materials has been efficiently coupled into the SiN waveguide, 159 in which the bandgaps of prevailing 2D semiconductors are suitable to the transmission window of the SiN, i.e., from UV to telecommunication wavelengths. Another opportunity for microcavity-enhanced 2D single-photon sources could be the exploration of room-temperature operation.…”

Nanocavity enhanced photon coherence of solid-state quantum emitters operating up to 30 K

“…Furthermore, similar methods can be extended to produce more complex resource states for optical quantum technologies, such as recent demonstrations of entangled graph states [16][17][18] where high fidelities are enabled by indistinguishable photons. Beyond QDs, the cavity-emitter concept has also been applied to realise photon sources using quantum emitters in other solid-state hosts such as diamond [19], silicon [20] and 2D materials [21]. At present, III-V QDs offer the most attractive platform due to their large dipole moment and relatively weak phonon coupling at low temperatures, enabling high brightness and indistinguishabilities.…”