Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Chiral cavity quantum electrodynamics with coupled nanophotonic structures

Fan Zhang, Juanjuan Ren, Lingxiao Shan, Xueke Duan, Yan Li, Tiancai Zhang, Qihuang Gong, Ying Gu

Published Nov 19, 2019• 37 citations
Publisher

Abstract

Up to now it remains challenging to couple photons from a circularly polarized emitter into a photonic structure to simultaneously realize strong photon-emitter interaction and unidirectional propagation locked by local helicity of the optical mode at the nanoscale. In this paper we propose a unique approach that combines a photonic crystal and metallic nanoparticle structure to create nanocavities with both strong local-field intensity and high helicity. In this system the rate of circularly polarized photons emitting into the photonic crystal waveguide reaches $148{\ensuremath{\gamma}}_{0}$, which is one order of magnitude larger than that without the nanoparticle, and in the ultranarrow band-edge mode the linewidth of Rabi splitting spectra is about one-tenth of that with the nanoparticle only, both with $\ensuremath{\approx}95%$ of photons propagating unidirectionally along the nanoscale waveguide. We suggest that our paper establishes a nanophotonic interface of chiral quantum electrodynamics for on-chip nonreciprocal quantum light sources, quantum circuits, and scalable quantum networks.

DOI
10.1103/physreva.100.053841

Related papers

A photonic interface of chiral cavity quantum electrodynamics

Zhang, Fan, Lingxiao Shan, Juanjuan Ren +5 more

Cavity quantum electrodynamics studies light-matter interactions at single quanta level. Chiral photon-emitter coupling in photonic structures is characterized as unidirectional propagation locked by the local polarization of light. However, to realize the strong interaction of photon-emitter with direction-locked propagation, which will bring novel applications in nonreciprocal quantum devices, has not been reported yet. Here, we propose the coupled photonic crystal and metallic nanoparticle structure, where through strong local field with high helicity, the rate of circularly polarized photons emitting into photonic crystal waveguide is one order larger than that without the nanoparticle and the linewidth of Rabi splitting spectra is about one-tenth of that with only the nanoparticle, both with $\sim$ 95$\%$ photons propagating unidirectionally, which can be utilized in directional quantum light sources.

arXiv:1808.07210•Aug 22, 2018•0 citations

Engineering Chiral Light–Matter Interactions in a Waveguide-Coupled Nanocavity

D. Hallett, Andrew P. Foster, David M. Whittaker +2 more

High Resolution Image Download MS PowerPoint Slide Spin-dependent, directional light–matter interactions form the basis of chiral quantum networks. In the solid state, quantum emitters commonly possess circularly polarized optical transitions with spin-dependent handedness. We demonstrate numerically that spin-dependent chiral coupling can be realized by embedding such an emitter in a waveguide-coupled nanocavity, which supports two near-degenerate, orthogonally polarized cavity modes. The chiral behavior arises due to direction-dependent interference between the cavity modes upon coupling to two single-mode output waveguides. Notably, an experimentally realistic cavity design simultaneously supports near-unity chiral contrast, efficient (>95%) cavity-waveguide coupling and enhanced light–matter interaction strength (Purcell factor F P > 70). In combination, these parameters enable the development of highly coherent spin–photon interfaces ready for integration into nanophotonic circuits.

arXiv:2108.01462•ACS Photonics•Jan 26, 2022•26 citations

Quantum optics in directional one-dimensional photonic reservoirs (Presentation Recording)

Immo Söllner, Peter Lodahl

We present a novel photonic crystal waveguide, engineered to support broadband modes with circular in-plane polarization. We show experimental evidence that for single-photon emitters with circular dipoles these waveguides act as near-lossless unidirectional photonic reservoirs, where the emission direction is given by the helicity of the dipole. This directional coupling has a strong effect on the scattering of single photons transmitted through the system and we discuss how counter-propagating photons acquire a relative phase of π. Combining this effect with photonic structures that can map a phase to a propagation path, we show how one can create nonreciprocal photonic elements.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 1, 2015•0 citations

A tunable chiral light-matter interface with on-chip spin control

Shikai Liu, Joan Alba, Bálint Sárközi +5 more

The ability to engineer chiral light-matter interactions is a valuable resource for realizing quantum networks and non-reciprocal quantum optics. Here, we demonstrate chiral coupling between light and a negatively charged exciton state, i.e., a four-level system, embedded in a standard photonic-crystal waveguide. By controlling the orientation and strength of an external magnetic field, we tune the polarization of the individual optical transition dipoles relative to the fixed elliptically polarized waveguide mode. In a two-sided waveguide, an optimized oblique magnetic field allows a selected transition to decay exclusively into a single propagation direction, enabling near-unity directional emission ($0.99^{+0.01}_{-0.02}$), despite the waveguide exhibiting imperfect polarization for chiral coupling. We further observe two tunable chiral branching ratios, the directional analogue of optical cyclicity, for two $Λ$-systems, with one reaching $134_{-77}^{+\infty}$. The magnetic-field-dependent spectroscopy also allows reconstruction of the local guided-mode polarization at the emitter via the Stokes parameters relative to the emitter's dipole moments. Finally, we demonstrate that this local chirality enables coherent control of an electron spin via an optical Raman process mediated by waveguide driving. Building on the simultaneous realization of a large branching ratio, directionality and spin control achieved at the same oblique magnetic-field angle, we propose a protocol with high tolerance to photon loss for generating high-fidelity remote spin-spin entanglement. Our magnetic control opens a reconfigurable and generic route for enhancing on-chip chiral spin-photon coupling in standard nanophotonic interfaces without the need to carefully engineer the polarization of the waveguide.

physics.opticsCross-listedarXiv:2609.06630•Sep 8, 2026•0 citations

On-chip chiral single-photon interface: Isolation and unidirectional emission

Lei Tang, Jiang-Shan Tang, Weidong Zhang +5 more

Chiral quantum systems have received intensive attention in fundamental physics and applications in quantum information processing including optical isolation and photon unidirectional emission. Here, we design an on-chip emitter-resonator system with strong chiral light-matter interaction for a chiral single-photon interface. The system includes a microring resonator with a strong evanescent field and a near-unity optical chirality along both of the whole outside and inside walls, allowing a strong and chiral coupling of the whispering-gallery mode to a quantum emitter. By initializing a quantum dot in a specific spin ground state or shifting the transition energy with a polarization-selective optical Stark effect, we show a broadband optical isolation at the single-photon level over several gigahertz. Furthermore, a quantum emitter chirally coupling to the microring resonator can emit single photons unidirectionally. Our protocol paves the way to realize a multifunctional chiral single-photon interface for on-chip quantum information processing and quantum networks.

arXiv:1811.02957•Physical Review A•Apr 24, 2019•118 citations

Quantum Dots in Photonic Crystal Waveguides: From Efficient Single Photon Sources to Deterministic Photon-Photon Interaction

Immo Söllner

This Thesis is focused on the study of quantum electrodynamics in photonic crystal waveguides. We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling eciencies for the spontaneous emission into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying eects, by obtaining coupling eciencies above 90% for quantum dots detuned from the band edge by as far as 20nm. These values are in good agreement with numerical simulations. Such a high coupling eciency implies that the system can be considered an articial 1D-atom, and we theoretically show that this system can generate strong photon-photon interaction, which is an essential functionality for deterministic optical quantum information processing. We present the progress towards the experimental demonstration of such a strong photon-photon nonlinearity. We present the rst signatures of resonant transmission in photonic crystal waveguides and discuss some of the encountered diculties and future directions of the experiments. In the nal part of this Thesis we discuss a novel type of photonic crystal waveguide and show its applications for on-chip quantum information processing. This structure was designed for the ecient mapping of two orthogonal circular dipole transitions to dierent propagation paths of the emitted photon, i.e. exhibits chiral quantum-dot-waveguide coupling. Such a structure is ideally suited for a number of applications in quantum information processing and among others we propose an on-chip spin-photon interface, a single photon transistor, and a deterministic cNOT gate.

•Jan 1, 2014•0 citations
Up to now it remains challenging to couple photons from a circularly polarized emitter into a photonic structure to simultaneously realize strong photon-emitter interaction and unidirectional propagation locked by local helicity of the optical mode at the nanoscale. In this paper we propose a unique approach that combines a photonic crystal and metallic nanoparticle structure to create nanocavities with both strong local-field intensity and high helicity. In this system the rate of circularly polarized photons emitting into the photonic crystal waveguide reaches 148\ensuremathγ0148{\ensuremath{\gamma}}_{0}148\ensuremathγ0​, which is one order of magnitude larger than that without the nanoparticle, and in the ultranarrow band-edge mode the linewidth of Rabi splitting spectra is about one-tenth of that with the nanoparticle only, both with \ensuremath≈95\ensuremath{\approx}95%\ensuremath≈95 of photons propagating unidirectionally along the nanoscale waveguide. We suggest that our paper establishes a nanophotonic interface of chiral quantum electrodynamics for on-chip nonreciprocal quantum light sources, quantum circuits, and scalable quantum networks.
Cavity quantum electrodynamics studies light-matter interactions at single quanta level. Chiral photon-emitter coupling in photonic structures is characterized as unidirectional propagation locked by the local polarization of light. However, to realize the strong interaction of photon-emitter with direction-locked propagation, which will bring novel applications in nonreciprocal quantum devices, has not been reported yet. Here, we propose the coupled photonic crystal and metallic nanoparticle structure, where through strong local field with high helicity, the rate of circularly polarized photons emitting into photonic crystal waveguide is one order larger than that without the nanoparticle and the linewidth of Rabi splitting spectra is about one-tenth of that with only the nanoparticle, both with ∼\sim∼ 95%\%% photons propagating unidirectionally, which can be utilized in directional quantum light sources.
High Resolution Image Download MS PowerPoint Slide Spin-dependent, directional light–matter interactions form the basis of chiral quantum networks. In the solid state, quantum emitters commonly possess circularly polarized optical transitions with spin-dependent handedness. We demonstrate numerically that spin-dependent chiral coupling can be realized by embedding such an emitter in a waveguide-coupled nanocavity, which supports two near-degenerate, orthogonally polarized cavity modes. The chiral behavior arises due to direction-dependent interference between the cavity modes upon coupling to two single-mode output waveguides. Notably, an experimentally realistic cavity design simultaneously supports near-unity chiral contrast, efficient (>95%) cavity-waveguide coupling and enhanced light–matter interaction strength (Purcell factor F P > 70). In combination, these parameters enable the development of highly coherent spin–photon interfaces ready for integration into nanophotonic circuits.
We present a novel photonic crystal waveguide, engineered to support broadband modes with circular in-plane polarization. We show experimental evidence that for single-photon emitters with circular dipoles these waveguides act as near-lossless unidirectional photonic reservoirs, where the emission direction is given by the helicity of the dipole. This directional coupling has a strong effect on the scattering of single photons transmitted through the system and we discuss how counter-propagating photons acquire a relative phase of π. Combining this effect with photonic structures that can map a phase to a propagation path, we show how one can create nonreciprocal photonic elements.
The ability to engineer chiral light-matter interactions is a valuable resource for realizing quantum networks and non-reciprocal quantum optics. Here, we demonstrate chiral coupling between light and a negatively charged exciton state, i.e., a four-level system, embedded in a standard photonic-crystal waveguide. By controlling the orientation and strength of an external magnetic field, we tune the polarization of the individual optical transition dipoles relative to the fixed elliptically polarized waveguide mode. In a two-sided waveguide, an optimized oblique magnetic field allows a selected transition to decay exclusively into a single propagation direction, enabling near-unity directional emission (0.99−0.02+0.010.99^{+0.01}_{-0.02}0.99−0.02+0.01​), despite the waveguide exhibiting imperfect polarization for chiral coupling. We further observe two tunable chiral branching ratios, the directional analogue of optical cyclicity, for two ΛΛΛ-systems, with one reaching 134−77+∞134_{-77}^{+\infty}134−77+∞​. The magnetic-field-dependent spectroscopy also allows reconstruction of the local guided-mode polarization at the emitter via the Stokes parameters relative to the emitter's dipole moments. Finally, we demonstrate that this local chirality enables coherent control of an electron spin via an optical Raman process mediated by waveguide driving. Building on the simultaneous realization of a large branching ratio, directionality and spin control achieved at the same oblique magnetic-field angle, we propose a protocol with high tolerance to photon loss for generating high-fidelity remote spin-spin entanglement. Our magnetic control opens a reconfigurable and generic route for enhancing on-chip chiral spin-photon coupling in standard nanophotonic interfaces without the need to carefully engineer the polarization of the waveguide.
Chiral quantum systems have received intensive attention in fundamental physics and applications in quantum information processing including optical isolation and photon unidirectional emission. Here, we design an on-chip emitter-resonator system with strong chiral light-matter interaction for a chiral single-photon interface. The system includes a microring resonator with a strong evanescent field and a near-unity optical chirality along both of the whole outside and inside walls, allowing a strong and chiral coupling of the whispering-gallery mode to a quantum emitter. By initializing a quantum dot in a specific spin ground state or shifting the transition energy with a polarization-selective optical Stark effect, we show a broadband optical isolation at the single-photon level over several gigahertz. Furthermore, a quantum emitter chirally coupling to the microring resonator can emit single photons unidirectionally. Our protocol paves the way to realize a multifunctional chiral single-photon interface for on-chip quantum information processing and quantum networks.
This Thesis is focused on the study of quantum electrodynamics in photonic crystal waveguides. We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling eciencies for the spontaneous emission into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying eects, by obtaining coupling eciencies above 90% for quantum dots detuned from the band edge by as far as 20nm. These values are in good agreement with numerical simulations. Such a high coupling eciency implies that the system can be considered an articial 1D-atom, and we theoretically show that this system can generate strong photon-photon interaction, which is an essential functionality for deterministic optical quantum information processing. We present the progress towards the experimental demonstration of such a strong photon-photon nonlinearity. We present the rst signatures of resonant transmission in photonic crystal waveguides and discuss some of the encountered diculties and future directions of the experiments. In the nal part of this Thesis we discuss a novel type of photonic crystal waveguide and show its applications for on-chip quantum information processing. This structure was designed for the ecient mapping of two orthogonal circular dipole transitions to dierent propagation paths of the emitted photon, i.e. exhibits chiral quantum-dot-waveguide coupling. Such a structure is ideally suited for a number of applications in quantum information processing and among others we propose an on-chip spin-photon interface, a single photon transistor, and a deterministic cNOT gate.