A Late-Model Optical Biochemical Sensor Based on OTS for Methane Gas and Glucose Solution Concentration Detection

Abstract

The traditional sensor structures are usually designed for single-function detection, but a dual-function optical biochemical sensor that can simultaneously detect methane (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) gas and glucose solution concentrationvia the change of refractive index (RI) is proposedin this paper,which is suitable for multiple application scenarios. Two kinds of cavities with different thicknesses are developed for gas and liquid measurement respectively. The sensitive and narrow absorption peak benefits from the optical Tamm state (OTS) based on the metal properties, which provides the basis for high-precision detection. By coating the CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -sensitive membrane, the qualitativea nd quantitative analysis of CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> concentration <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{CH4}$ </tex-math></inline-formula> of 0–3% (RI of 1.4364–1.4478) can be accurately realized. The sensitivity (S) is 7.89 THz/RIU, the figure of merit (FOM) is up to 1315, the quality (Q) value is 88832, and the lower detection limit (DL) is about 3.8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$ </tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-5}$ </tex-math></inline-formula> . If such a sensor is used to detect the concentration of glucose aqueous solution ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{G}$ </tex-math></inline-formula> ) of 140–330 g/L (RI of 1.3489–1.3715), the corresponding values are 2.55 THz/RIU, 319, 66601, and 1.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$ </tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-4}$ </tex-math></inline-formula> , which can provide the possibility for the biomedicine blood glucose detection. In addition, the effects of different metal layer thicknesses on sensor performance are discussed briefly.