Fiber Optic Sensor of Ammonia Gas Using Plasmonic Extraordinary Optical Transmission

Area of Science:

• Plasmonics
• Nanophotonics
• Chemical Sensing

Background:

• Standard surface plasmon resonance sensing is well-established.
• Plasmonic nanostructured arrays for sensing, particularly gas sensing, are less explored.
• Extraordinary optical transmission (EOT) offers potential for novel sensing platforms.

Purpose of the Study:

• To demonstrate an ammonia gas sensor based on plasmonic nanostructured arrays.
• To combine fiber optics, EOT, and a chemo-optical transducer for gas detection.
• To investigate the sensing mechanism and compare experimental data with theoretical predictions.

Main Methods:

• Fabrication of a gold nanostructured periodic hole array using focused ion beam milling.
• Integration of a chemo-optical transducer (a metallic dye in PDMS matrix) sensitive to ammonia.
• Characterization of spectral transmission using fiber optics and analysis of extraordinary optical transmission (EOT) spectra.
• Theoretical modeling using the rigorous Fourier modal method (FMM).

Main Results:

• The developed system demonstrated selective spectral sensitivity to ammonia gas.
• Observed visible-near-infrared (VIS-NIR) EOT spectra correlated well with FMM predictions.
• The study provides insights into the gas sensing mechanism of the EOT system.

Conclusions:

• Plasmonic nanostructured arrays combined with EOT and fiber optics offer a promising approach for gas sensing.
• The chemo-optical transducer exhibits selective spectral sensitivity to ammonia.
• Theoretical modeling aids in understanding and optimizing plasmonic sensing systems.