Enhanced Sensitivity for the Detection of Tuberculosis Based on Optical Biosensor at Terahertz Band Spectrum

Abstract

Tuberculosis still remains a significant worldwide public health hazard, mostly due to insufficient political will to allocate resources for its elimination, unlike the response to diseases such as COVID-19. It has the highest fatality rate in one particular infection, higher than the other. In this study, we propose a hollow-core photonic crystal fiber (PCF) sensor optimized for tuberculosis detection in the terahertz (THz) spectrum. The sensor features an octagonal core with strategically placed air holes, enhancing light confinement and interaction with tuberculosis-infected blood samples. Using finite element method (FEM)-based simulations in COMSOL Multiphysics 5.6, we evaluated key performance parameters, including relative sensitivity (RS), confinement loss (CL), effective material loss (EML), effective area (EA), and numerical aperture (NA). The presented study provides the construction of a PhCs fiber sensor featuring a sensitive, uncomplicated core designed for the detection of tuberculosis at terahertz frequencies. This sensor can precisely identify TB bacteria in each strain and successfully differentiate among them. The new indicators have a high RS of 98.29% and lower overall losses of 3.30 × 10−1 dB/m compared to older detectors that used PCF. The sensor under evaluation has a confinement loss of 4.65 × 10⁻¹³ dBm⁻¹, an extremely low EML of 0.33 dBm⁻¹, and a NA of 0.273. This sensor guarantees optimal sensitivity for the detection of tuberculosis. The physical architecture of this sensor is easy, facilitating its construction with modern manufacturing methods. The sensor is therefore ready to improve the detection and treatment of aggressive tissues.