Abstract:
The photonic crystal fiber (PCF) sensor has emerged as an innovative technology, driven by distinctive features such as low loss, heightened sensitivity, exceptional resolution, swift response times, manageable dispersion, birefringence, label-free detection capabilities, smart and compact design, good enough sensor resolution and more. Focusing on these unique properties, various PCF-based sensors are developed and proposed for novel purposes. This study explores sensor design from a dual perspective, examining both hollow core PCF and porous core PCF sensors for detecting liquids and greenhouse gases. Additionally, PCF-based surface plasmon resonance (PCF-SPR) sensors are customized for detecting sensitive liquids and various cancer cells. Precise adjustments, including air hole diameters, lattice spacing, air-filling fractions (AFFs), gold layer thickness, analyte layer thickness, and the perfectly matched layer (PML), significantly enhance sensor performance. In PCF-based liquids and gas sensing, interactions occur at specific wavelengths within the PCF sensing unit. During these interactions, liquids and gases absorb light wavelengths based on their energy levels, resulting in reduced light signal intensity indicative of successful detection. In the realm of PCF-SPR sensors, the refractive index (RI) difference between the core and cladding enables the core to release light, interacting with plasmonic material and generating a surface plasmon wave (SPW) through the collective oscillation of free electrons at the metal-dielectric interface. Resonance occurs when the wavelengths of photons and electrons synchronize, facilitating optimum energy transfer from core mode to surface plasmon polariton (SPP) mode. The resulting resonance peak loss curve aids in identifying analytes. The COMSOL Multiphysics has been used for designing the fibers, the finite element method has been employed for simulation and data generation, while MATLAB has been utilized for analyzing data by plotting curves. Note that during the simulation process, HC-PCF detects CH4 and CO2 with sensitivities of 97% and 93.2%, respectively. PC-PCF excels in detecting C2H5OH with a sensitivity of 63%, while HPC-PCF detects H2O with a sensitivity of 67%. In real-world applications, PCF-SPR sensors exhibit high sensitivity, with single-sided polish achieving a peak wavelength sensitivity of 9000 nm/RIU and a maximum amplitude sensitivity of 3746 RIU−1, and double-sided polish achieving a peak wavelength sensitivity of 7143 nm/RIU and a maximum amplitude sensitivity of 270 RIU−1. The PCF-based sensors are widely deployed across various fields, including the detection of liquids and gases, temperature and pressure sensing, environmental monitoring for safety, and assisting doctors in identifying various types of cancer cells within the human body, thereby enhancing patient care and diagnostic capabilities. These sensors have also found widespread application beyond these realms.