On-chip spin-orbit locking of quantum emitters in 2D materials for chiral emission

Abstract

Light carries both spin angular momentum (SAM) and orbital angular momentum (OAM), which can be used as potential degrees of freedom for quantum information processing. Quantum emitters are ideal candidates towards on-chip control and manipulation of the full SAM–OAM state space. Here, we show coupling of a spin-polarized quantum emitter in a monolayer W S e 2 with the whispering gallery mode of a S i 3 N 4 ring resonator. The cavity mode carries a transverse SAM of σ = ± 1 in the evanescent regions, with the sign depending on the orbital power flow direction of the light. By tailoring the cavity–emitter interaction, we couple the intrinsic spin state of the quantum emitter to the SAM and propagation direction of the cavity mode, which leads to spin–orbit locking and subsequent chiral single-photon emission. Furthermore, by engineering how light is scattered from the WGM, we create a high-order Bessel beam which opens up the possibility to generate optical vortex carrying OAM states.

Advances in Metaphotonics Empowered Single Photon Emission

“…This phase variation resulted in the generation of circularly polarized outgoing single photons at room temperatures and without strong magnetic fields, eliminating thereby the experimental requirements crucial for many other experiments. [98,105,106,110,111] This work experimentally demonstrated the single-photon emission with a well-defined spin angular momentum (SAM) (with the chirality > 0.8) and high directionality (collection efficiency up to 92%). [38,112] Besides SAM-encoded single-photon generation, on-chip room temperature realization of single-photon emission with the OAM associated with helical wavefronts can open up an unprecedented opportunity for high-capacity information processing.…”

“…Chiral single‐photon emission was also realized by coupling strain‐induced QEs in monolayer WSe 2 to the whispering gallery mode of a Si 3 N 4 ring resonator. [ 106 ] In this configuration, QEs are created over the edge of the ring resonator, which inherently couples the spin‐locking mode of the ring resonator via the evanescent field (Figure 4d). The photon emission with opposite spin states was observed at low temperatures from the QE and ring resonator with polarization characteristics originating from the interaction between the QE spin states and the spin‐dependent chirality of the cavity mode.…”

“…This phase variation resulted in the generation of circularly polarized outgoing single photons at room temperatures and without strong magnetic fields, eliminating thereby the experimental requirements crucial for many other experiments. [ 98,105,106,110,111 ] This work experimentally demonstrated the single‐photon emission with a well‐defined spin angular momentum (SAM) (with the chirality > 0.8) and high directionality (collection efficiency up to 92%). [ 38,112 ]…”

“…[ 105 ] d) On‐chip spin‐orbit locking of QEs in 2D materials for chiral emission. [ 106 ] a) Reproduced with permission. [ 98 ] Copyright 2015, Springer Nature.…”

Integrated Optical Vortex Microcomb

“…Compared to other on-chip solutions of vortex beam generators, e.g., metasurfaces 12,13 and fork gratings 14 , microresonator vortex emitters benefit from strong light-matter interactions due to the prolonged photon lifetimes and enhanced light intensities. For example, spontaneous and stimulated emissions can be dramatically enhanced by the cavity quantum electrodynamics effect, facilitating the realization of highly-efficient OAM single-photon sources 15,16 and low-threshold vortex microlasers [17][18][19] . Hitherto, optical vortex emitters based on either passive or active microrings are operated monochromatically.…”