Slow-Wave Hybrid Magnonics

ABSTRACT

Cavity magnonics represents a burgeoning research frontier that explores the interaction between magnons and cavity photons. Such platforms hold unique advantages by combining the strengths of both magnonic and microwave systems, promising applications in quantum transduction, dark matter detection, and neuromorphic computing. However, cavity magnonics relies on the enhancement effect of microwave resonances to achieve coherent interaction, which is inherently narrowband and thus limits the operational bandwidth. In practical applications, it is highly desired to develop non-resonant structures that support traveling photons to achieve large bandwidths for magnon-photon interaction without sacrificing the coupling strength, but it is extremely challenging due to the lack of cavity enhancement. This challenge is particularly pronounced in integrated devices where micro/nano-magnonic devices interface with microstrips or coplanar waveguides (CPWs).

To tackle this challenge, we introduced a novel concept termed slow-wave hybrid magnonics in our recent work. Previously, slow lights have been employed to enhance light-matter interactions and introduce new functionalities in optics. By incorporating spoof surface plasmon polariton (SSPP) structures, we extended the concept of slow waves to microwave photons and, for the first time, merged the two promising fields – spoof plasmonics and cavity magnonics – into a new platform that enabled broadband hybrid magnonic interactions. Importantly, large coupling strengths were achieved on such travelling-wave (non-resonant) platforms, facilitating intricate system dynamics crucial for complex magnonic systems such as magnonic crystals and networks. More interestingly, a new phenomenon of slow-wave strong coupling was observed on our platform. In addition, we demonstrated an example application of slow-wave hybrid magnonics in studying broadband magnon-phonon interactions. With its novel properties and great potential, our slow-wave hybrid magnonic system opens a new direction for hybrid magnonics and can be potentially extended to other hybrid magnonics systems such as optomagnonics and magnomechanics.

BIOGRAPHY

Dr. Xufeng Zhang received his Ph.D. in Electrical Engineering from Yale University in 2016 and was award the Henry Prentiss Becton Graduate Prize for exceptional research achievements. After graduation, he joined Argonne National Laboratory as the Nikola Tesla Named Postdoctoral Fellow and was promoted in 2018 as an Assistant Scientist. In 2022 he joined the Department of Electrical and Computer Engineering at Northeastern University as an assistant professor. He has a diverse research interest in device physics and applications, with a focus on an experimental study of spin wave dynamics and magnonic devices that are hybridized with microwave/photonic/mechanical components for coherent and quantum information processing. Dr. Zhang has published over 50 peer-reviewed journal articles, and his pioneering works on magnon-photon/phonon coupling are among the first experimental demonstrations of hybrid magnonics. Dr. Zhang led multiple research projects funded by DOE, DARPA, and NSF, and he is the recipient of the 2023 Young Investigator Award from the Office of Naval Research.