Peak amplitude difference sensitivity (PADS): An interrogation technique for PCF-SPR sensors using symmetrical arrays of plasmonic layers

In this research paper, plasmonic materials are used in some arrays consisting of gold and aluminum-doped zinc oxide (AZO) to make a unique photonic crystal fiber sensor with multiple loss peaks. Using plasmonic layer arrays, a unique dispersion relation with several peaks has been introduced. Compared to a sensor with a single peak, the proposed sensor has multiple peaks that can be applicable for different wavelength range to detect the refractive index efficiently. A new interrogation technique named Peak Amplitude Difference Sensitivity (PADS) is proposed in this manuscript while in this sensor, the maximum PADS of 396.175 RIU−1 and maximum wavelength sensitivity (WS) of 85,300 nm/RIU is achieved. Furthermore, the sensor has a high wavelength resolution of 1.17×10-6 RIU. With an ultra-high linearity of R2=0.99978, this sensor obtained a high figure of merit (FOM) of 370.8 RIU−1, indicating precise detection accuracy. The proposed design can lead to major improvements in the ultra-high precision in detecting the biological organic molecules and can be used in extensive applications.