Theory Design of a Virtual Polarizer with Multiscale and Multi-Biomass Sensing.

Area of Science:

• Terahertz (THz) technology
• Biosensing
• Optical physics

Background:

• Growing societal focus on human health necessitates advanced detection methods.
• Existing biosensing technologies face limitations in multiscale and multi-biomass detection.
• Polarization conversion and absorption phenomena offer potential for novel sensing mechanisms.

Purpose of the Study:

• To design and demonstrate a virtual polarizer (VP) for multiscale and multi-biomass sensing.
• To investigate the VP's capability for detecting temperature variations, cancerous cells, and COVID-19.
• To evaluate the sensing performance, including sensitivity, quality factor, figure of merit, and detection limit.

Main Methods:

• Utilizing coherent perfect polarization conversion within the 1.72–2.14 THz range.
• Observing the displacement of a perfect matching point (PMP) for temperature sensing (299 K–315 K).
• Employing a sharp coherent perfect absorption (CPA) peak for cancerous cell and COVID-19 detection via refractive index (RI) changes.

Main Results:

• Accurate temperature determination with a sensitivity of 0.0198 THz/K.
• Cancerous cell detection with RI sensitivity of -4.45881 THz/RIU, Q=825.36, FOM=241.11 RIU⁻¹, DL=-36.83 dB.
• COVID-19 detection across concentrations (0–525 mM) with RI sensitivity of -5.03467 THz/RIU, Q=760.85, FOM=244.94 RIU⁻¹, DL=-36.89 dB.

Conclusions:

• The proposed VP demonstrates effective multiscale and multi-biomass sensing capabilities.
• The VP achieves excellent detection performance for temperature, cancerous cells, and COVID-19.
• This technology presents a novel and promising approach for advanced biosensing applications.