Highly Sensitive Magneto-Optical SPR Sensor Based on the Photonic Spin Hall Effect With CeYIG and Graphene

This work studies a magneto-optical surface plasmon resonance (MOSPR) sensor design that uses the photonic spin Hall effect (PSHE) concept, including cerium-substituted yttrium iron garnet (CeYIG) and graphene to allow for very sensitive detection of magnetic fields at 632.8 nm. When subjected to a magnetic field, the CeYIG layer exhibits anisotropic optical behavior, explained by a permittivity tensor with nonzero off-diagonal components, thereby inducing magneto-optical (MO) activity. The magnetization is oriented along the z-axis, normal to the sensor surface. Notably, the proposed design achieves an extraordinary transverse spin-dependent shift (SDS) of approximately 237.93 μm with the external orbital angular momentum (EOAM) based centroid shift of 0.508 μm at resonance angle. This enhancement has enabled the MOSPR sensor to use as an ultra-sensitive PSHE-based magnetometer, with a maximal sensitivity of 11258.36 μm/RIU at a refractive index (RI) of 1.1 for detecting minute RI variations in the sensing medium. The proposed MOSPR sensor, performance enhanced by the integration of CeYIG and graphene with PSHE, demonstrates the importance of this sensor for next-generation MO sensing devices.