Nonreciprocal cavity magnonics system for amplification of photonic spin Hall effect

Nonreciprocal cavity magnonics combines magnetics and photonics to provide a versatile platform for studying nonlinear interactions and spin–orbit coupling in optical systems. We present a theoretical framework to amplify the photonic spin Hall effect (SHE) in a nonreciprocal cavity magnonics system with two microwave cavity modes and a single magnon mode. By tuning the coupling strengths between clockwise (CW) and counterclockwise (CCW) microwave modes and magnons, we achieve a high isolation rate I>50, indicating high nonreciprocity. Using the transfer matrix approach, we compute the reflection coefficients of transverse magnetic (TM) and transverse electric (TE) polarized light, demonstrating amplified photonic SHE via control of CW and CCW coupling rates. The nonlinear dynamics arising from asymmetric spin splitting and enhanced photon-magnon interactions exhibit intriguing effects such as dynamic spin–orbit coupling, paving the way for advanced spin photonic devices. This study highlights the potential of cavity magnomechanics to extend the understanding of nonreciprocal phenomena and provides a pathway to developing spin-based photonic circuits, optical isolators, and polarization-sensitive devices for nonlinear optical applications.