Broadband molecular sensing with a tapered spoof plasmon waveguide

Area of Science:

• Optoelectronics
• Chemical Sensing
• Plasmonics

Background:

• Accurate identification of low concentration chemical mixtures is crucial.
• Broadband enhanced infrared absorption (BEIRA) offers a potential solution.
• Existing methods may lack sensitivity or broad spectral coverage.

Purpose of the Study:

• To propose and numerically study a corrugated parallel plate waveguide (CPPW) for enhanced chemical sensing.
• To demonstrate the capability of CPPW in broadband sensing applications.
• To investigate the tunability of the waveguide for specific frequency ranges.

Main Methods:

• Numerical simulation of a corrugated parallel plate waveguide (CPPW) with gradient grooves.
• Analysis of the conversion of transmission modes to surface plasmon modes.
• Calculation of the transmission coefficient for sensing toluene and ethanol thin layers.

Main Results:

• The CPPW design facilitates direct conversion of transmission to surface plasmon modes.
• Broadband sensing of toluene and ethanol thin layers was successfully demonstrated.
• The waveguide's transmission spectrum precisely matched the infrared spectra of the analytes.
• Bandgap tuning was achieved by adjusting groove heights, enabling frequency range customization.

Conclusions:

• The proposed CPPW is a powerful and effective platform for broadband chemical sensing.
• The device shows high sensitivity for identifying low concentration chemical mixtures.
• The tunable nature of the CPPW makes it adaptable for various sensing applications.