https://doi.org/10.1140/epjs/s11734-026-02240-y
Regular Article
Plasmonic sensor using carbon nano-material for detection of bio-chemical fluids
1
Department of Electrical and Electronics & Communication Engineering, DIT University, 248009, Dehradun, Uttarakhand, India
2
Department of Electronics and Communication Engineering, Netaji Subhas University of Technology, 110078, Dwarka, Delhi, India
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Received:
25
November
2025
Accepted:
26
February
2026
Published online:
19
March
2026
Abstract
A new photonic crystal fiber (PCF)-based plasmonic refractive index sensor is proposed and numerically investigated for detection and analysis of water in chemicals and human body fluids. The proposed sensor has been designed for the detection and analysis of fluids based on variation of refractive index (RI) in the range from 1.33 to 1.4 RIU. The shape of the sensor is D type with an innovative squircle shape analyte cavity with plasmonic materials, such as carbon nanotube (CNT) layer on flat surface and nickel filling in air holes of the sensor. To compare quality of performance of sensor parameters, two combinations of nickel filling with and without air holes have been simulated for study. The core of the PCF is designed to allow interaction between the guided light and the analyte of interest. The evanescent field measurement is done after filling sample analyte into the squircle shape tube guided through the sensor. The full-vector finite element method (FVFEM) was used to evaluate the proposed sensor in the near infrared spectrum. The sensor performance evaluation is done by comparing sensor parameters of confinement loss (CL), wavelength sensitivity (WS), amplitude sensitivity (AS), resolution (R), full wave half maximum (FWHM), and figure of merit (FOM) of the two design variations with earlier reported designs. The change in refractive index induces a shift in the resonant wavelength and change in confinement loss in the sensor. The wavelength sensitivity of 12,000 nm/RIU with a resolution of 4.17 × 10–7 RIU, FWHM in the range from 64 to 57 nm, and FOM in the range from 188 to 211 RIU−1 have been achieved with the nickel and air holes combination in one type. In another design variation, nickel was introduced to fill the remaining air holes. This configuration achieved a wavelength sensitivity of 12,000 nm/RIU with a resolution of 4.17 × 10–7 RIU, a FWHM ranging from 63 to 60 nm, and FOM in the range from 190 to 200 RIU−1 has been recorded. The proposed designs are found to be highly sensitive, cost-effective with good linear characteristics (R2 = 0.99) in the RI range from 1.33 to 1.4 RIU, making it suitable for sensing of biological samples of human origin and water adulteration in chemical sample.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
