Multi-functional photonic spin Hall effect sensor controlled by phase transition

Abstract Photonic spin Hall effect (PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index (RI). In this work, we propose a multi-functional PSHE sensor based on VO 2 , a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO 2 can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO 2 is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO 2 is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO 2 is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO 2 layers, which is very simple and elegant. Therefore, the proposed VO 2 -based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.