Deflection-based laser sensing platform for selective and sensitive detection of H2S using plasmonic nanostructures.

Considering the severe hazards of abnormal concentration level of H2S as an extremely toxic gas to the human body and due to the disability of olfactory system in sensing toxic level of H2S concentration, a reliable, sensitive, selective and rapid method for the detection of H2S is proposed and its efficacy is analyzed through simulation. The proposed system is based on the deflection of a laser beam in response to the temperature variations in its path. In order to provide selectivity and improve sensitivity, gold nanostructures were employed in the system. The selectivity was introduced based on the thiol-gold interactions and the sensitivity of the system was enhanced due to the modification of plasmon resonance behavior of gold nanostructures in response to gas adsorption. Results from our analysis demonstrate that compared with Au and SiO2-Au, the Au nanomatryoshka structures (Au-SiO2-Au) showed the highest sensitivity due to promoting higher deflections of the laser beam.