The water content sensor in heavy oil based on one-dimensional photonic crystals

Abstract

An ultra-compact sensor, based on a one-dimensional (1D) photonic crystal (PhC) of alternate layers of SiO2 and TiO2 with a defect layer in the middle, was proposed for measuring the water content in heavy oil. The reflection properties for heavy oil containing different water content filled in the defect layer were studied by the transfer matrix method (TMM) and the results show that the defect mode, appearing in the photonic band gap (PBG) of PhC shifts to longer wavelength region with increasing the refractive index of the defect layer introduced in the PhC. An average sensitivity of Δg1/Δλ=0.021nm−1 is achieved, indicating that the water content in heavy oil can be calculated according to the change in the wavelength of defect modes.