Electromagnetic Anapole-Inspired Micro-Displacement Sensor Using Dual-Layer Terahertz Metasurfaces With Micrometer-Level Sensitivity and Centimeter-Level Range

Micro-displacement sensor utilizing dual-layer terahertz metasurfaces structure is proposed and examined in this study. The sensor manipulates the excited electromagnetic anapole mode, characterized by a distinct resonance peak frequency and strong resonance intensity, to measure micrometer-level displacements precisely, providing high sensitivity and resolution. Due to its ingenious structural design, the proposed sensor demonstrates an exceptional capacity for continuously measuring displacements spanning multiple periods. The measurement results suggest that the proposed design achieves a centimeter-scale displacement detection range with a sensitivity of 0.28 GHz/
$\mu $
m. Compared to established micro-displacement measurement techniques, this approach presents a pioneering and viable solution to the longstanding challenge of noncontact precise position detection with a wide range from a spectrum measurement perspective.