Ultra-sensitive multi-tasking photonic spin Hall effect sensor controlled by external pressure

The photonic spin Hall effect (SHE) is an effective metrological approach to monitor the subtle change of refractive index (RI). In this work, we theoretically propose a highly sensitive RI sensor based on photonic SHE, which can flexibly manipulate multiple sensing tasks by taking advantage of the tunable RI of polymer layer via the external pressure. In the measured RI range of 1.32–1.39, a great enhancement of sensing performance is observed under the condition of optimal pressure (0–200 MPa). Moreover, we take the two distinct detection tasks (identifying cancer cells and detecting oxyhemoglobin concentration) as examples, and then demonstrate the multi-functional sensing potential, and also high sensitivity. Therefore, our designed photonic SHE sensor with the simple structure of only four layers, could integrate multiple RI sensing tasks into one device. These findings not only make up for the shortcomings of single-function in traditional sensors and complex structure in multi-functional ones, but more significantly, they offer a new opportunity for real-time, label-free, flexible manipulation, and low-cost detection in the field of biomedicine.