Inverse designed plasmonic metasurface with parts per billion optical hydrogen detection

Area of Science:

• Nanotechnology
• Optics
• Materials Science

Background:

• Plasmonic sensors utilize optical resonances in metal nanoparticles.
• Current optical hydrogen sensors using palladium (Pd) nanostructures have limited detection capabilities, typically in the parts-per-million (ppm) range, due to broad spectral features and optical losses.
• Improving the sensitivity of these sensors is crucial for accurate hydrogen detection.

Purpose of the Study:

• To overcome the limitations of broad spectral features in plasmonic sensors for hydrogen detection.
• To design and demonstrate a plasmonic metasurface with enhanced sensitivity for hydrogen sensing.
• To achieve a significantly lower detection limit for hydrogen gas compared to existing methods.

Main Methods:

• Employed an inverse design approach using a particle swarm optimization algorithm to identify optimal plasmonic metasurface parameters.
• Fabricated a periodic array of palladium (Pd) nanoparticles as the sensing element.
• Numerically simulated and experimentally validated the sensor's performance.

Main Results:

• Demonstrated a plasmonic sensor with a narrow spectral linewidth and enhanced optical field confinement within the Pd nanoparticles.
• Achieved a record hydrogen detection limit of 250 parts-per-billion (ppb).
• The developed sensor shows a significant improvement over state-of-the-art plasmonic hydrogen sensors.

Conclusions:

• Inverse design is a powerful strategy for optimizing plasmonic metasurfaces for ultrasensitive optical gas detection.
• The demonstrated Pd nanoparticle metasurface offers a significant advancement in hydrogen sensing technology.
• This approach has broad implications for developing highly sensitive optical sensors for various analytes.