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 proposed a multi-functional PSHE sensor based on VO2, a material that exhibits phase transition behavior. By applying thermal control, the mutual transformation on different phase states of VO2 can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO2 is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO2 is in a mixed phase, the designed structure can discriminate the normal and cancer cells with no-label and real-time monitoring. When VO2 is metallic, the proposed PSHE sensor can act as a RI pointer for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design only consists of one analyte and two VO2 layers, which is very simple and elegant. Therefore, the proposed VO2-based PSHE sensor with outstanding advantages of small size, high sensitivity, no-label, and real-time detection, offers new ideas for the research of tunable multi-functional sensors.