Microwave-optical interactions

Dean B. Anderson, R. R. August, WILLIAM A. McDOWELL

Tretiakov, Andrei

Information transfer between a microwave field and light, also known as microwave-to optical transduction, is a key area of research in quantum communication technology aimed at developing an interface between the superconducting processing devices operating at microwave frequencies and optical photons used for transferring quantum information over distance. Atomic vapors offer a good platform for such interfaces since they naturally support transitions at microwave and optical frequencies. In this work, we explored microwave-to-optical transduction in rubidium ensembles. We proposed a transduction method based on microwave-optical double resonance, where we can control the ensemble optical properties via non-linear interactions with a microwave magnetic field. With this method, we demonstrate the transduction of an audio signal from frequency-modulated and amplitude-modulated microwave fields to optical intensity modulation. We also present a protocol for engineering atomic spin polarization with microwave-assisted optical pumping and consider its applications for polarization-selective frequency conversion and microwave-controlled optical rotation.

Zhiyuan Fan, Liu Qiu, Simon Gröblacher +1 more

Abstract Microwave‐optics entanglement is a vital component for building hybrid quantum networks. Here, a new mechanism for preparing stationary entanglement between microwave and optical cavity fields in a cavity optomagnomechanical system is proposed. It consists of a magnon mode in a ferrimagnetic crystal that couples directly to a microwave cavity mode via the magnetic dipole interaction and indirectly to an optical cavity through the deformation displacement of the crystal. The mechanical displacement is induced by the magnetostrictive force and coupled to the optical cavity via radiation pressure. Both the opto‐ and magnomechanical couplings are dispersive. Magnon–phonon entanglement is created via magnomechanical parametric down‐conversion, which is further distributed to optical and microwave photons via simultaneous optomechanical beamsplitter interaction and electromagnonic state‐swap interaction, yielding stationary microwave‐optics entanglement. The microwave‐optics entanglement is robust against thermal noise, which will find broad potential applications in quantum networks and quantum information processing with hybrid quantum systems.

A. Vainsencher, G. A. Peairs, Kevin J. Satzinger +1 more

Qianjun Zheng, Wenxue Zhong, Guangling Cheng +1 more

We propose a theoretical scheme for the generation of nonreciprocal microwave-optical entanglement in a magnon-based hybrid system where an optical photon in a spinning resonator is coupled to a phonon representing the quantum of the mechanical deformation of a yttrium iron garnet crystal via radiation pressure. Meanwhile, the magnon interacts with the phonon and the microwave through the magnetostrictive and magnetic dipole–dipole interactions, respectively. By spinning the resonator, the light driven in opposite directions propagates irreversibly, which leads to the classical nonreciprocity of mean optical photon numbers. Strikingly, the nonreciprocal entanglement between microwave and optical photons can be generated owing to the Fizeau light-dragging effect. Physically, the magnon–phonon entanglement induced by the magnomechanical parametric downconversion interaction is partially transferred to the microwave-optical subsystem through magnon-microwave and optomechanical state-exchange interactions. Moreover, the nonreciprocity of entanglement can be manipulated by properly choosing various system parameters and the ideal nonreciprocal microwave–optical entanglement could be achieved, in which the entanglement depending on the effective optical detuning is present in a chosen direction but disappears in the other direction. Our work could be applied in the multi-task quantum information processing and construction of chiral quantum networks.