Ultrahigh-sensitivity optical spin Hall effect sensor based on bismuth-doped amorphous glass in the visible light region

During the process of tissue clearing, the refractive index matching solution (BABB) is highly susceptible to environmental factors. Even slight changes in refractive index can result in blurred deep-tissue imaging. Here, the combination of amorphous glass and the spin Hall effect of light (SHEL) can address this challenge. A series of (49-x) P2O5-30Nb2O5-9BaO-12Na2O-xBi2O3 (PNBN-xBi, 0 ≤ x ≤ 9) amorphous glasses are prepared by using the melt-quenching method. All samples exhibit a complete amorphous glass network structure. The introduction of Bi3+ not only densifies the glass network structure but also enables a wide range of tunable refractive indices (1.585–1.762). The PNBN-3Bi sample with refractive index matching properties is used as the reference standard to successfully enhance the SHEL in weak measurement system. A visible-light-band SHEL sensor for the precise detection of BABB is designed using self-developed amorphous glass and microfluidic channels. In the high-response refractive index range of 1.55–1.60, the sensor's sensitivity can reach up to 17 667 μm/RIU. This work demonstrates that amorphous glass-based SHEL sensors offer advantages of real-time detection, ultrahigh sensitivity, and selectable measurement ranges, providing new insights for trace component control and concentration detection.