Research on optical fiber SPR sensing technology enhanced by halloysite nanotubes

In this paper, a transmission fiber optic sensor based on surface plasmon resonance (SPR) was proposed to measure refractive index and temperature, which is enhanced by halloysite nanotubes(HNTs). The sensor employs a transmission structure with a gold film as the metal layer for exciting SPR. HNTS are then deposited on the gold film using electrostatic adsorption as a material to enhance the sensor's sensitivity. This allows for measuring refractive index sensitivity changes in the external solution. By encapsulating HNTs with a layer of PDMS, temperature can also be measured. Experimental results demonstrate that the sensor, enhanced by HNTs, achieves a refractive index sensitivity of 4147nm/RIU and a temperature sensitivity of -4.51nm/°C. The use of HNTs as an enhancing material offers low cost and simple fabrication, as well as strong biocompatibility and a large specific surface area. These unique features make the proposed HNTs-SPR sensor great prospects for high-sensitivity detection of biochemical quantities in the field of optical fiber sensing.