GST-enhanced fiber SPR curvature sensor

This paper proposes a high-sensitivity surface plasmon resonance (SPR) curvature sensor based on hard polymer-clad fiber (HPCF). The sensor utilizes an HPCF coated with gold and Ge₂Sb₂Te₅ (GST), with a layer of polydimethylsiloxane (PDMS) as the sensing medium for curvature measurement. GST enhances the sensor's sensitivity by increasing the dielectric constant of the metal layers. The sensor exhibits high sensitivity and can identify bending direction, with sensitivities of 1.74 nm/m^-1 for positive x-direction bending and 6.21 nm/m^-1 for negative x-direction bending. This sensor offers a novel solution for high-sensitivity curvature measurement with a wide measurement range and directional recognition capabilities.