Microwave interference between a spin ensemble and its mirror image
Journal article, 2026
We investigate microwave interference between a spin ensemble and its mirror image in a one-dimensional (1D) waveguide. Away from the mirror, the resonance frequency of the Kittel mode (KM) inside a ferrimagnetic spin ensemble displays sinusoidal shifts (compared to a setup without the mirror) as a function of the distance to the mirror. Furthermore, the radiative decay of the KM into the waveguide shows a cosine-squared oscillation as the distance to the mirror is varied. These shifting frequencies and decay rates are a consequence of the KM's interaction with its own image, mediated by the waveguide. The decay is enhanced twofold when the spin ensemble sits at the magnetic antinode of the corresponding eigenmode in the waveguide; conversely, we measure an extension of the KM lifetime by a factor of 8 when the spin ensemble is approximately at a node. We can finely tune the KM decay rate to achieve maximal absorption of input photons at a critical coupling point. Moreover, by pumping the spin ensemble to generate a pump-induced magnon mode in a two-tone experiment, we achieve a pump-induced phase shift of up to about 90 degrees for a coherent microwave probe field.
Author
B. -Y. Wu
City University of Hong Kong
Y. -T. Cheng
City University of Hong Kong
K. -T. Lin
Hon Hai Research Institute
National Taiwan University
F. Aziz
National Tsing Hua University
City University of Hong Kong
C. -X. Run
City University of Hong Kong
K. -M. Hsieh
City University of Hong Kong
J. -C. Liu
Hong Kong University of Science and Technology
K. -V. Rangdhol
City University of Hong Kong
Y. -Y. Yeung
City University of Hong Kong
Sen Yang
Hong Kong University of Science and Technology
Qiming Shao
Hong Kong University of Science and Technology
Xin Wang
City University of Hong Kong
Y. -Y. Zhao
Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area
Anton Frisk Kockum
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
G. -D. Lin
National Center for Theoretical Sciences (NCTS)
National Taiwan University
Hon Hai Research Institute
Franco Nori
RIKEN
University of Michigan
I. -C. Hoi
City University of Hong Kong
PHYSICAL REVIEW A
2469-9926 (ISSN) 2469-9934 (eISSN)
Vol. 113 5 053720Quantum simulation and communication with giant atoms
Swedish Foundation for Strategic Research (SSF) (FFL21-0279), 2022-08-01 -- 2027-12-31.
Open Superconducting Quantum Computers (OpenSuperQPlus)
European Commission (EC) (EC/HE/101113946), 2023-03-01 -- 2026-08-31.
Subject Categories (SSIF 2025)
Condensed Matter Physics
DOI
10.1103/swf5-ynd5