Fiber Optic Sensor’s Performance Enhancement by Tuning NIR Wavelength, Polarization, and 2D Material

Fiber optic evanescent wave sensor consisting of chalcogenide core, silica clad, and 2D material (graphene and MoS
₂
) monolayer is simulated and analyzed in near infrared (NIR) aiming at highly sensitive and reliable detection of malignancies in human liver tissues. Dispersion relations of normal and malignant human liver tissues are considered. The sensor’s performance is examined in terms of sensitivity and resolution. The analysis indicates that using MoS
₂
as 2D material provides enhanced (nearly two-fold) performance compared with graphene. At 1200-nm wavelength, the sensitivity achieved is nearly 93.7 mW/RIU (real index) and 548.30 mW/RIU (imaginary index) whereas resolution achievable is of the order of 10
⁻⁹
RIU (real index) and 10
⁻¹⁰
RIU (imaginary index). Longer NIR wavelength should be used and p-polarization provides significantly better performance compared with s-polarization. With lesser photodamage and reduced Rayleigh scattering (due to being operated in NIR), the proposed sensor probe also has the ability to deliver considerably finer resolution than the current lot of fiber optic sensors based on different techniques. The limitations of the proposed sensor model are also discussed.