Atmospheric carbon dioxide profile detection with a continuous-wave differential absorption lidar

Differential absorption Lidar (DIAL) is a powerful technique for remote sensing of atmospheric carbon dioxide (CO2). After decades of continuous evolution, traditional pulsed-based CO2 DIAL has made great progress and gradually comes into applications, but unfortunately these setups still face some dilemmas, such as complex structure, high cost, and poor maintainability. These inherent defects hinder the large-scale promotion application of traditional pulsed-based CO2 DIAL. Here, we demonstrated a 1.57 mu m continuous-wave differential absorption lidar (CW-DIAL) for atmospheric CO2 profile detection based on the Scheimpflug principle with a high dynamic range near-infrared (SWIR) array detector. A tunable SWIR distributed-feedback (DFB) laser is used as the seed light source, feeds to a self-made erbium-ytterbium co-doped fiber amplifier and obtain final output power to about 3 W of 1.57 mu m. A reflective telescope is employed to collect the atmospheric backscattered signal which is finally shapely imaged in a high dynamic range InGaAs array detector. Multiple atmospheric CO2 profiles were obtained over 3000 m with a cumulative measurement time of 2010s and a range resolution of 100 m. The detection results were also compared with a CO2 Sensor (GMP343), yielding a correlation coefficient of 0.99962 and a relative error of 1 %. The preliminary results confirm our developed CW-DIAL has the ability to detect the spatiotemporal distribution of atmospheric CO2. Given its compact structure, low power consumption and cost, it has enormous potential application in many areas for the range-resolved CO2 concentration profiles detection.