Novel Merger of spectroscopy and refractive index sensing for modelling hyper sensitive hexa-slotted plasmonic sensor for transformer oil monitoring in near-infrared region

This research presents a novel link between refractive index sensing and spectroscopy by designing a "photonic crystal fiber" based "refractive index (RI)" sensor. The proposed sensor is based on the "surface plasmon resonance" phenomenon. The sensor monitors the transformer oil (To) moisture content as moisture depletes its quality. The change in the moisture content changes the RI of the transformer oil. Thus, the presented sensor can identify the minimal change in the RI of the To. The sensor is designed to operate in the RI range of 1.33 - 1.34RIU, with a step size of 0.002. Using the wavelength interrogation method, the proposed sensor's wavelength sensitivity is 25,000 nm/RIU and 22,500 nm/RIU along X-polarization (X-pol.) and Y-polarization (Y-pol.), respectively. The amplitude interrogation technique is used to calculate the amplitude sensitivity obtained from the proposed sensor, which is 17080RIU(-1) and 18690RIU(-1) corresponding to X-pol. and -pol., respectively. The sensor resolution of the sensor is 4.00 x 10(-6) RIU and 4.44 x 10(-6) RIU corresponds to X-pol. and Y-pol., respectively. Full-width half maximum obtained from the proposed sensor is 73nm and 55nm for X- and Y-pol., respectively. The figure of merit obtained from the presented sensor is 342.46RIU(-1) and 409.09RIU(-1) for X- and Y-pol., respectively. Thus, the prospective sensor can act as an ideal device for the quality assessment of To.