Recently, Gao Xiaoming, a research team of Anguang Institute, Hefei Research Institute, Chinese Academy of Sciences, developed a new spectrometer that can simultaneously remotely monitor methane (CH4), water (H2O) and nitrous oxide (N2O) in the atmosphere. Relevant research achievements have been published in Optics Express under the title of "A MEMS modular based dual channel mid infrared laser heterodyne radiator for simultaneous remote sensing of atmospheric CH4, H2O and N2O".
In the mid infrared band, due to the lack of mature optical fiber components or optical waveguides, traditional mechanical choppers are usually used to modulate sunlight, which makes it difficult to miniaturize the spectrometer system. To solve this problem, the team developed a dual channel mid infrared laser heterodyne spectrometer based on MEMS modulator. They used MEMS galvanometer to replace the traditional mechanical chopper. Xue Zhengyue, the first author of the study, said: "This makes the system more stable and smaller.". They also combined two inter band cascade lasers, which enables the developed heterodyne spectrometer to simultaneously measure the gas volume mixing ratio of CH4, H2O and N2O.
Through inversion calculation, the team obtained the laser heterodyne spectrum in Hefei. The experimental results show that the measured volume mixing ratio of CH4, H2O and N2O is in good agreement with the simulated spectrum of atmospheric transmission. Therefore, the dual channel mid infrared laser heterodyne spectrometer based on MEMS modulator has broad application prospects. The associate researcher Tan Tu said, "This research achievement has laid a certain foundation for further developing a portable hyperspectral resolution laser heterodyne spectrometer for remote sensing detection of atmospheric multi-component gases".
This research work was supported by the key programs of the National Natural Science Foundation of China and the national key research and development plan.
Source: Yangtze River Delta Laser Alliance
