Level attraction and level repulsion of magnon coupled with a cavity anti-resonance

Abstract

We report on coherent and dissipative coupling between a magnon mode and an anti-resonance of transmission in a cylindrical microwave cavity. By effectively suppressing coherent coupling, we observe the hybridized dispersion to change from level repulsion to level attraction. A careful examination reveals distinct differences in the line shape and phase evolution of transmission spectra between these coupling behaviors. For a quantitative understanding of the interactions between the magnon mode and the cavity anti-resonance, we develop a model which precisely describes our experimental observations, particularly, the signature in the line shape and phase of the microwave transmission. Our work sets a foundation for understanding strong coupling between magnon modes and cavity anti-resonances. In addition, it also confirms the ubiquity of level attraction in coupled magnon-photon systems, which may be helpful to develop future magnon-based hybrid quantum systems.

Interferometric control of magnon-induced nearly perfect absorption in cavity magnonics

“…Due to the destructive interference induced by double drives, the maximum response of the system deviates from its eigenfrequencies in the frequency domain, and thus LA-like hybridization occurs (see Supplementary Note 5 ). This unique hybridization behavior in cavity magnonics was previously observed in 1D Fabry-Perot cavities 37 , 45 , cavity anti-resonance 40 , planar cavities 41 – 43 , and two-tone driven CMPs 38 , 44 . In these works, LA was treated as a signature of the dissipative coupling effect.…”

“…This interference is tunable by both the strength and the direction of an external magnetic field, and can modify magnetically induced transparency (MIT) into a level attraction (LA)-like hybridization in the transmission. Different from previously reported systems with dissipative coupling [35][36][37][38][39][40][41][42][43][44][45][46] , negative mass 47 , or negative energy [48][49][50][51][52][53] , LA-like hybridization in our device is a special transmission response produced by destructive interference. This hybridization eliminates transmission and allows perfect absorption (96% in the experiment and 100% in the theory reported in this work).…”

Interactions between a magnon mode and a cavity photon mode mediated by traveling photons

“…All these experimental observations well confirm our theoretical predictions. Our work clarifies the mechanism of dissipative coupling mediated by traveling photons, which is useful for us to understand the recently discovered dissipative coupling [20,[29][30][31][32][33][34][35][36][37] and giant nonreciprocity [20] in cavity magnonics systems. Additionally, the physics and technique developed in our work may help us design a new hybrid system based on waveguide magnonics.…”

Nonreciprocity and Unidirectional Invisibility in Cavity Magnonics

“…However, in conventional cavity magnonics systems governed by coherent magnon-photon coupling, nonreciprocity is missing [43]. Last year, an intriguing dissipative magnon-photon coupling was discovered [44,45], which has quickly been verified as ubiquitous [46][47][48][49][50][51][52]. Microscopically, dissipative coupling results from the traveling-wave-induced [51] cooperative external coupling [23,52,53].…”