Magnetically controllable photon blockade under a weak quantum-dot–cavity coupling condition

Abstract

Quantum control of photons has become an area of great interest in the development of quantum technology. Here we explore how an external magnetic field can be exploited to control the statistical properties of photons in a bimodal cavity quantum electrodynamics (CQED) system. Our CQED system is composed of a bimodal micropillar Fabry-P\'erot cavity containing a single $V$-level quantum dot (QD) involving fine-structure-splitting neutral exciton transitions under the effect of the applied magnetic field in the presence of an incident pump laser field driving one cavity mode. With the introduction of the external magnetic field, not only is the conversion of polarization characteristics of photons achieved, but the statistics properties of photons are well engineered and the switching between photon bunching and antibunching is realized in the weak-coupling regime of CQED. The superiority of our system is manifested in the following aspects. (i) Using experimental parameters, we can manipulate the statistical properties of photons by appropriately tuning the strength of the magnetic field under the weak-coupling CQED condition, accompanied by either enhanced antibunching or a transition from antibunching to strong bunching of the light and vice versa. So we can arrive at selective photon statistics. (ii) The strong photon antibunching effect, under nonresonant scenarios but without the need to match the resonant or near-resonant conditions for the cavity and QD, can appear. Furthermore, we find that the multifrequency photon blockade can be generated in the present system, which is different from previous studies about photon blockade only for specific optical detuning. (iii) The high photon occupations or transmissions, simultaneously accompanied by strong photon antibunching in the system, are beneficial to the correlation measurement in practical experiments. This process works with a high quality of photon antibunching and bunching over a wide range of parameters and has potential applications in on-chip quantum information processing. It is hoped that the proposed scheme provides a possibility for the generation of tunable single-photon sources or controllable photon quantum gates.