MANIPULATION OF SPATIAL FIELD DISTRIBUTION IN A PLANAR MICROWAVE PHOTON-MAGNON CONVERTER

Subject and Purpose. The research addresses planar photon-magnon (P-M) converters that efficiently convert between microwave photons and magnons and are essential components in emerging quantum technologies. Planar P-M converters benefit particularly from planar, two-dimensional (2D) resonators. Among them are asterisk-shaped resonators featuring compact geometry and strong concentration of the magnetic component of the electromagnetic (EM) field. The present work seeks an effective approach to optimizing planar P-M converters to enhance conversion efficiency and further miniaturize the device by manipulating the spatial distribution of the high-frequency magnetic field.

Methods and Methodology. The proposed approach relies on numerical simulations of the electrodynamic response of the asterisk-shaped resonator coupled to the feeding microstrip line. Families of the resonance spectra are analyzed as a function of the resonator’s position relative to the microstrip line, which effectively varies the electromagnetic coupling strength. This methodology allows systematic optimization of the resonator’s geometrical and spectral parameters, enabling targeted manipulation of the magnetic field distribution across the magnetic sample location.

Results. The conducted analysis has demonstrated that a fine adjustment of the P-M coupling strength can maximize the concentration of the magnetic component of the high-frequency EM field at a desired location within the resonator. Practical recommendations have been developed for designing high-performance planar P-M converters, offering a framework for the efficient integration of asterisk-shaped resonators into miniaturized quantum devices.

Conclusions. Based on the numerical analysis of the spectral properties of a 2D asterisk-shaped split-ring resonator (ASRR) intended for a planar microwave P-M converter, it has been shown that selecting the optimal position for the feeding microstrip line allows a high concentration of the magnetic component of the EM field at the resonator center. Proper positioning of the mi- crostrip feeding line is important for achieving a relatively high Q-factor (Q ≈ 200) for operating modes. The calculated resonance spectra of the investigated P-M converter identify ranges of the resonator offset parameter where dynamic manipulation of the P-M coupling strength is possible and relatively simple.