Trace-level fuel contaminant detection using an ultrasensitive HC-photonic crystal fibre sensor

Abstract

Fuel adulteration involving the illicit mixing of substances such as kerosene and diesel with petrol poses significant risks to engine performance, environmental safety and consumer health. This paper presents a novel HC-PCF sensor designed to accurately detect and identify adulterants in petroleum-based fuels with unprecedented sensitivity and selectivity. The proposed HC-PCF sensor features a unique circular core structure surrounded by a carefully engineered square cladding region, enabling highly sensitive detection of refractive index changes caused by the presence of adulterants. Through rigorous numerical simulations and optimisation, our design achieves remarkable maximum relative sensitivities of 98.56%, 98.95%, and 99.32% for petrol, kerosene, and diesel, respectively, outperforming many previously reported techniques. A comprehensive analysis of the sensor's performance reveals an ultra-low confinement loss of 4.08 × 10⁻¹⁰ dB/m, 1.08 × 10⁻¹³ dB/m, and 2.95 × 10⁻¹² dB/m and effective material loss of 0.0040 cm⁻¹, 0.0036 cm⁻¹, and 0.0034 cm⁻¹, highlighting its exceptional light-guiding capabilities and sensitivity. The sensor's high responsiveness facilitates the detection of even trace levels of adulterants by capturing minute refractive index variations as low as possible, enabling real-time monitoring and timely intervention in adulteration incidents. The proposed HC-PCF sensor exhibits high selectivity, precisely targeting the refractive index signatures of fuels, ensuring accurate detection even in complex chemical environments. Its compact size and robust design make it suitable for deployment in various fuel quality control applications, from transportation to industrial settings. Overall, this work introduces cutting-edge HC-PCF sensor technology that addresses the critical need for reliable fuel adulteration detection with unparalleled sensitivity and selectivity, contributing to enhanced product quality, consumer protection, and environmental sustainability in the energy sector.