Ultra-wide measurement range D-shaped photonic crystal fiber sensor based on surface plasmon resonance

In this paper, a kind of D-type photonic crystal fiber (PCF) sensor with an ultra-wide detection range based on micro-opening gold film coating is proposed. This sensor allows for the sensing detection of the refractive index (RI) of the analyte ranging from 1.30 to 1.42. However, the sensor coated with a micro-opening gold film only achieves an average wavelength sensitivity of 1489 nm/RIU in the x-polarization direction. To improve the performance of the sensor, an attempt was made to replace the micro-opening gold film with MoO₂ nanofilm. After simulation calculation, it was found that the RI detection range of the sensor using MoO₂ nanofilm became 1.33–1.39. Excitingly, the average wavelength sensitivity in the x-polarized direction reaches 17, 178 nm/RIU, which is 11.5 times better than the original sensor. This implies that the sensor is more sensitive to changes in the RI and can provide more accurate sensing and detection results. It has been demonstrated that the performance of a D-type PCF sensor can be significantly improved by using MoO₂ nanofilm. This improvement helps to expand the application domain of sensors and enhance the accuracy of sensing detection. We believe that this research result has important implications for the development of fiber sensor technologies.

Graphical Abstract

Ultra-wide refractive index detection range fiber optic sensor