Abstract We investigate the single-photon blockade (1PB) in the quasichiral regime of atom–photon interaction, where the effective coupling between the cavity and the atom is bidirectional but asymmetrical, achieved by coupling to a dissipative environment. A synthetic magnetic current ϕ is induced in the closed-loop coupling, which breaks down the reciprocity of atom–photon interaction, and can be utilized to create asymmetrical or even unidirectional effective coupling between two selected quantum states. As an example, we couple the single-atom cavity quantum electrodynamics (QED) system to a strongly dissipative plasmonic cavity. We find that in the quasichiral regime, the unconventional photon blockade (UPB) and the conventional photon blockade (CPB) realize simultaneously in the condition of maximum chirality (ϕ = π/2 and 3π/2). As a result, 1PB in the quasichiral regime can combine the advantages of both UPB and CPB, demonstrating the perfect single-photon purity, higher efficiency, non-oscillating time dynamics as well as lower requirement of mode coupling to achieve UPB. Our work paves the way for 1PB towards practical applications and reveals the intriguing quantum-optics phenomena in the quasichiral light–matter interaction.Abstract We investigate the single-photon blockade (1PB) in the quasichiral regime of atom–photon interaction, where the effective coupling between the cavity and the atom is bidirectional but asymmetrical, achieved by coupling to a dissipative environment. A synthetic magnetic current ϕ is induced in the closed-loop coupling, which breaks down the reciprocity of atom–photon interaction, and can be utilized to create asymmetrical or even unidirectional effective coupling between two selected quantum states. As an example, we couple the single-atom cavity quantum electrodynamics (QED) system to a strongly dissipative plasmonic cavity. We find that in the quasichiral regime, the unconventional photon blockade (UPB) and the conventional photon blockade (CPB) realize simultaneously in the condition of maximum chirality (ϕ = π/2 and 3π/2). As a result, 1PB in the quasichiral regime can combine the advantages of both UPB and CPB, demonstrating the perfect single-photon purity, higher efficiency, non-oscillating time dynamics as well as lower requirement of mode coupling to achieve UPB. Our work paves the way for 1PB towards practical applications and reveals the intriguing quantum-optics phenomena in the quasichiral light–matter interaction.

arXiv:2112.14227New Journal of PhysicsApr 25, 202210 citations

Optical-assisted Photon Blockade in a Cavity System via Parametric Interactions

H. Y. Sun, Cheng Shang, Xiangning Luo +2 more

International Journal of Theoretical PhysicsAug 28, 20195 citations

Asymmetric synchronous single-photon blockade induced by parametric interactions

Shiyan Li, Nan Wang, Ai‐Dong Zhu +1 more

We propose a scheme to achieve asymmetric synchronous photon blockade (PB) in a system composed of two optical cavities coupled through a nonlinear crystal. By regulating the input direction of the pump light, either single-cavity PB or two-cavity synchronous PB can be selectively realized based on the incidence direction. This asymmetry arises from parametric up- and down-conversion processes induced by the pump light incoming from opposite directions. The delayed correlation function further demonstrates the high temporal resolution of the synchronized single photons generated in both cavities. This scheme enables flexible control over different types of PB by simply tuning the pump direction, without any modifications to system components. Moreover, the two-cavity synchronous PB mechanism provides an efficient approach for single-photon heralding, holding the potential to surmount the commonly encountered issue of low collection efficiency in probabilistic single-photon sources.We propose a scheme to achieve asymmetric synchronous photon blockade (PB) in a system composed of two optical cavities coupled through a nonlinear crystal. By regulating the input direction of the pump light, either single-cavity PB or two-cavity synchronous PB can be selectively realized based on the incidence direction. This asymmetry arises from parametric up- and down-conversion processes induced by the pump light incoming from opposite directions. The delayed correlation function further demonstrates the high temporal resolution of the synchronized single photons generated in both cavities. This scheme enables flexible control over different types of PB by simply tuning the pump direction, without any modifications to system components. Moreover, the two-cavity synchronous PB mechanism provides an efficient approach for single-photon heralding, holding the potential to surmount the commonly encountered issue of low collection efficiency in probabilistic single-photon sources.

Optics ExpressAug 28, 20251 citation

Photon blockade and single-photon generation with multiple quantum emitters

Mingyuan Chen, Jiang-Shan Tang, Lei Tang +2 more

Generation and manipulation of single photons are at the heart of photon-based quantum information processing. An ensemble of quantum emitters (QEs) as a versatile light-matter interface are very promising for quantum technology such as quantum storage and repeater. However, it is commonly believed that many QEs are unable to create photon blockade and generate single photons with high purity due to the multiexcitation effect. Here, we show efficient photon blockade and single-photon generation with a few to ten QEs by suppressing multiexcitation with a detuned auxiliary cavity. Because the auxiliary cavity induces a strong dipole-dipole interaction among the QEs, these QEs can be treated as a two-level superatom. By coupling this superatom to another collecting cavity, efficient photon blockade with a high transmission is obtained. With the same setup, single-photon emission can also be achieved with yield and purity larger than $90%$ simultaneously even in the bad-cavity limit. Our method may open up a simple route to generate and manipulate single photons on demand.Generation and manipulation of single photons are at the heart of photon-based quantum information processing. An ensemble of quantum emitters (QEs) as a versatile light-matter interface are very promising for quantum technology such as quantum storage and repeater. However, it is commonly believed that many QEs are unable to create photon blockade and generate single photons with high purity due to the multiexcitation effect. Here, we show efficient photon blockade and single-photon generation with a few to ten QEs by suppressing multiexcitation with a detuned auxiliary cavity. Because the auxiliary cavity induces a strong dipole-dipole interaction among the QEs, these QEs can be treated as a two-level superatom. By coupling this superatom to another collecting cavity, efficient photon blockade with a high transmission is obtained. With the same setup, single-photon emission can also be achieved with yield and purity larger than $90%$ simultaneously even in the bad-cavity limit. Our method may open up a simple route to generate and manipulate single photons on demand.

Physical Review ResearchJul 29, 202233 citations

90%

simultaneously even in the bad-cavity limit. Our method may open up a simple route to generate and manipulate single photons on demand.