Nonlinear Split-Ring Resonator for Controlling the Strong Photon-Magnon Coupling Strength

The strong coupling effect between magnons and photons in a nonlinear split-ring shaped resonator was studied numerically. It has been shown that in the nonlinear regime, a structure with a variable capacitor Cv=0.1 pF exhibits a maximum value of the strength of strong coupling between photons and magnons <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{g} / 2 \pi=52 \text{MHz})$</tex> with a strength of coupling normalized per spin (coupling of a single-spin photon) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$g/2\pi\sqrt{N}= 0.1605 \text{Hz}$</tex> at a frequency of 1.163 GHz. The possibility of tuning the frequency of resonance of the studied resonant structure by varying the degree of nonlinearity of the electrodynamic processes occurring within it has been demonstrated. Namely, we have shown that in the nonlinear regime, the control of the frequency of resonance of the structure and the magnitude of photon-magnon coupling by varying the input power Pin is possible. Additionally, an increase in photon-magnon coupling with decreasing variable capacitor capacitance was observed.