High-Sensitivity Janus Sensor Enabled by Multilayered Metastructure Based on the Photonic Spin Hall Effect and Its Potential Applications in Bio-Sensing

• Published in: Sensors (Basel, Switzerland) Vol. 24; no. 17; p. 5796
• Main Authors: Li, Xiang, Zhang, Haifeng
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 06.09.2024
• Subjects: Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Blood Glucose - analysis; Design; Electric fields; electromagnetic waves propagation; Electromagnetism; Humans; Janus effect; Measurement techniques; multilayered metastructure; optical biological detection; Optics; photonic spin Hall effect; Photons; Plasma; Propagation; Refractometry; Sensors; Janus effect; optical biological detection; multilayered metastructure; electromagnetic waves propagation; photonic spin Hall effect
• DOI: 10.3390/s24175796
• ISSN: 1424-8220

The refractive index (RI) of biological tissues is a fundamental material parameter that characterizes how light interacts with tissues, making accurate measurement of RI crucial for biomedical diagnostics and environmental monitoring. A Janus sensor (JBS) is designed in this paper, and the photonic spin Hall effect (PSHE) is used to detect subtle changes in RI in biological tissues. The asymmetric arrangement of the dielectric layers breaks spatial parity symmetry, resulting in significantly different PSHE displacements during the forward and backward propagation of electromagnetic waves, thereby realizing the Janus effect. The designed JBS can detect the RI range of 1.3~1.55 RIU when electromagnetic waves are incident along the +z-axis, with a sensitivity of 96.29°/refractive index unit (RIU). In the reverse direction, blood glucose concentrations are identified by the JBS, achieving a sensitivity of 18.30°/RIU. Detecting different RI range from forward and backward scales not only overcomes the limitation that single-scale sensors can only detect a single RI range, but also provides new insights and applications for optical biological detection through high-sensitivity, label-free and non-contact detection.