Recently, Liu Kun and other researchers at Anhui Institute of Aeronautics and Astronautics, Department of Atmospheric Physics and Chemistry, made new progresses in the study of high-sensitivity miniaturized absorption spectrum sensing technology. Research results published in Sensors & Optical sensing technology based on absorption spectrum is widely used in the fields of atmosphere, environment and industry for its advantages of real-time on-line, high sensitivity, high selectivity and non-invasiveness. In order to increase the sensitivity of the absorption spectrum sensing, the optical multi-pass absorption cell is often used to increase the interaction length between the light and the sample. However, due to the limitations of spot overlap and other factors, the traditional optical absorption cell (such as the Herriott cell) is difficult to achieve hundreds of light reflection, long optical path can only be obtained by increasing the physical pool length, thus greatly increasing the absorption cell Of the volume, it is difficult to achieve small, portable high-sensitivity sensing device. Liu Kun and other researchers through careful design, the general spherical reflector to achieve reflected light spot was seven circles distribution, make full use of the reflector's reflection surface, in the case of non-coincidence of light spots to achieve up to 215 times the light reflection , Thus achieving an effective optical path length of 26 meters with a base length of 12 cm. Liu Kun and other researchers used the new optical absorption cell designed to carry out the measurement of methane (CH4) in the atmosphere, achieving 100ppb (10-9) detection sensitivity and better than 80ppb measurement accuracy. The research results provide an effective tool for developing miniaturized and portable high-sensitivity optical sensors and will also promote the application of volumetric and weight-demanding UAV atmospheric detection technologies. The research is funded by the National Natural Science Foundation of China, the Chinese Academy of Sciences Youth Promotion Association and other funding. Spot distribution in the mirror surface Atmospheric methane (CH4) results were measured for 2 consecutive days paper