Photonic Spin Hall Effect-Based AQI Sensor: Effect of Concentration of PM₂.₅
Lokesh Ahlawat, Kamal Kishor, Monu Nath Baitha, Ravindra Kumar Sinha
Abstract
The current study proposes an air quality index (AQI) sensor based on the photonic spin Hall effect (PSHE). It senses the changes in AQI caused by the variations in the concentration of particulate matter (PM<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${}_{{2}.{5}}\text {)}$ </tex-math></inline-formula>. The layered structure utilizes the surface plasmon resonance (SPR) mechanism for PSHE shifting and enhancement. The present study reports an enhanced PSHE shift of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1888~\mu $ </tex-math></inline-formula> m. The proposed AQI sensor possesses a sensitivity of 42.0349°/RIU and a figure of merit (FOM) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.2\times 10^{{6}}$ </tex-math></inline-formula>/RIU. The PSHE shift (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\delta }_{{r}\pm }^{H}\text {)}$ </tex-math></inline-formula> also shows a switching response upon change in AQI range, which may serve as an indicator of high pollution level.