High-performance CO detection based on a PhC cavity in terahertz band

Area of Science:

• Optics and Photonics
• Chemical Sensing
• Materials Science

Background:

• Photonic crystal (PhC) cavities offer potential for gas detection by utilizing light absorption from molecular vibrations.
• Developing selective and sensitive sensors for toxic gases like carbon monoxide (CO) is crucial.

Purpose of the Study:

• To propose and numerically analyze a novel PhC cavity for highly sensitive and selective carbon monoxide detection.
• To investigate the sensor's performance in the terahertz band to minimize interference from other gases.

Main Methods:

• Design and simulation of a PhC cavity with a high-quality factor (1.24 × 10^6) and small mode volume (2.3 × 10^-4 (λ/n)^3).
• Numerical analysis of the cavity's response to carbon monoxide at terahertz frequencies.
• Assessment of interference from water (H2O) and carbon dioxide (CO2).

Main Results:

• The proposed PhC cavity demonstrated high selectivity and sensitivity for CO detection.
• Numerical analysis confirmed the sensor's potential for practical application with linear fitting of results.
• Interference from H2O and CO2 was found to be negligible, enabling CO detection without pre-drying.

Conclusions:

• The developed PhC cavity exhibits excellent performance characteristics for CO sensing.
• The sensor's high selectivity and robustness against common interfering gases make it a competitive option for toxic gas detection.
• This technology supports on-site CO monitoring without the need for sample pre-treatment.