Silicon-based double fano resonances photonic integrated gas sensor

Area of Science:

• Photonics
• Nanotechnology
• Chemical Sensing

Background:

• Telecommunication wavelengths are vital for photonic integrated circuits (PICs).
• Gas absorption lines within these wavelengths enable miniaturized PIC-based gas sensors.
• Silicon metasurfaces offer a platform for developing advanced optical devices.

Purpose of the Study:

• To present a novel silicon metasurface design featuring double Fano resonances for selective gas sensing.
• To engineer Fano resonances within the 1.52–1.7 μm telecommunication band.
• To develop a dual-detection sensor for carbon monoxide (CO) and nitrous oxide (N2O).

Main Methods:

• Designing periodically coupled nanodisk and nanobar resonators on a quartz substrate.
• Tuning geometrical parameters to engineer Fano resonances.
• Utilizing Fano resonances for refractometric sensing of CO and N2O.

Main Results:

• Achieved double Fano resonances within the telecommunication band.
• Developed a sensor with high sensitivity (1,735 nm/RIU) and FOM (11,570) for CO at FR1.
• Demonstrated sensitivity (194 nm/RIU) and FOM (510) for N2O at FR2.
• Observed selective absorption losses for CO (6.3%) at FR1.

Conclusions:

• The proposed silicon metasurface enables highly sensitive, selective, and dual-target gas sensing.
• The design shows significant promise for miniaturized refractometric photonic integrated gas sensors.
• The engineered Fano resonances allow for precise tuning of sensing capabilities.