Mid-infrared high-sensitive cavity-free in-situ CO gas sensing based on up-conversion detection
Abstract
Carbon monoxide (CO) is a significant indicator gas with considerable application value in atmospheric monitoring, industrial production and medical diagnosis. Its fundamental vibrational band locates around 4.6 m and has larger absorption line strength than that of overtone band, which is more suitable for the precise identification and concentration detection of CO. In this paper, the up-conversion detection is employed to convert the mid-infrared absorption signal obtained by TDLAS to the visible light band, then a silicon-based detector is utilized for detection. By which, we can achieve the highest sensitivity of 79.6 ppb under the condition of cavity-free in-situ with an absorption range length of only 0.14 m. Furthermore, the single-photon level real-time detection of CO concentration after the diffuse reflection is realized by using SPAD. This work demonstrates the merits of the up-conversion detection in terms of its functionality at room temperature and capacity for sensitivity detection. Furthermore, it presents a design and optimization methodology that has the potential to underpin the advancement of the method towards more practical applications, like industrial process monitoring, medical diagnosis and so on.
Cite
@article{arxiv.2601.15981,
title = {Mid-infrared high-sensitive cavity-free in-situ CO gas sensing based on up-conversion detection},
author = {Zhao-Qi-Zhi Han and He Zhang and Fan Yang and Xiao-Hua Wang and Bo-Wen Liu and Jin-Peng Li and Zheng-He Zhou and Yin-Hai Li and Yan Li and Zhi-Yuan Zhou and Bao-Sen Shi},
journal= {arXiv preprint arXiv:2601.15981},
year = {2026}
}