China University of Science and Technology uses a hybrid magneto-optical force system to achieve tunable microwave-light conversion

The team of Academician Guo Guangcan of our university has made new progress in the research of magneto-optical force hybrid system. Professor Chunhua Dong's research group of the team made direct contact between the optical force microcavity and the magneton microcavity, proving that the hybrid system supports the coherent coupling of magneton-phonon-photon, and thus realizes the tunable microwave-light conversion. The research results were published in the international academic journal Physics Review Letters on December 9, 2022.

Different quantum systems are suitable for different quantum operations, including atomic and solid-state systems such as rare-earth doped crystals, superconducting circuits, spins in yttrium iron garnets (YIG), or diamonds. By using phonons as the intermediary, the coupling regulation of different quantum systems can be realized, and finally the hybrid quantum network can be constructed to give full play to the advantages of different quantum systems. At present, optical radiation pressure, electrostatic force, magnetostrictive effect and piezoelectric effect have been widely used in the coupling of mechanical vibrators with optical photons, microwave photons or magnetons. These interaction mechanisms have promoted the rapid development of the field of optomechanics and magnetic machinery. In previous work, the team used the good tunable properties of the magnetons in the YIG microcavity to achieve tunable single sideband microwave-optical conversion in combination with the magneto-optical effect (Photonics Research 10, 820 (2022)). However, due to the large mode volume of magneto-optical crystal microcavity, the quality factor is difficult to further breakthrough, which limits the intensity of magneto-optical interaction, resulting in low microwave-light conversion efficiency. In contrast, cavity light force systems have achieved efficient microwave-light wave conversion, but are limited in practical applications due to the lack of tunability.

Figure Note: a-b. Schematic diagram of the magneto-optical force hybrid system, which supports magneton-phonon-photon coherent coupling; c. Microwave-optical conversion.

In this work, the research team developed a hybrid system consisting of a photoforce microcavity and a magneton microcavity. In the system, phonons can be electrically controlled by magnetostriction effect and optically controlled by optical radiation pressure, and phonons in different microcavities can be coherently coupled by direct contact of microcavities. Based on the high quality optical mode sensitive measurement of the mechanical state, the research team achieved a microwave-optical conversion with a tuning range of up to 3GHz, which is much higher than the conversion efficiency of previous magneto-optical single systems. In addition, the team observed the interference effect of mechanical motion, in which the optically driven mechanical motion can be cancelled out by the coherent mechanical motion driven by microwaves. Overall, the magneto-optic force system provides an effective hybrid experimental platform for manipulating light, sound, electricity and magnetism, and is expected to play an important role in the construction of hybrid quantum networks.

Zhen Shen, Guanting Xu and Mai Zhang are co-first authors of the paper, and Chunhua Dong is corresponding author of the paper. The above research was supported by the Key Research and Development Program of the Ministry of Science and Technology, the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Cutting-edge Collaborative Innovation Center for Quantum Information and Quantum Technology.

Attached paper link:https://link.aps.org/doi/10.1103/PhysRevLett.129.243601

(Key Laboratory of Quantum Information, Chinese Academy of Sciences; Institute of Quantum Information and Quantum Technology Innovation, Chinese Academy of Sciences; School of Physics; Department of Scientific Research)