One of the most in-demand LIDAR applications is involved with atmospheric composition studies: measuring the atmospheric content of various gases and impurities, including toxic substances.
The most accurate results in air pollution control, environmental monitoring, and atmospheric composition determination at different altitudes are obtained with systems using the differential absorption method (DIAL). These systems feature a possibility to perform sensing with narrowband laser emission at two neighboring wavelengths.
In 2020, specifically for Zuev Institute of Atmospheric Optics (leading institution of the Russian Federation in the field of lidar research), engineers of our company developed a dual-channel laser system for the remote monitoring of methane concentration (CH4) in lowest atmospheric paths.
The laser system is based on the DPSS laser model QX500; it provides synchronous lasing at 3428.18 nm and 3422.05 nm.
The system design allows fine wavelength tuning at each channel, thus providing operation in the methane absorption line, on the one hand, and getting in the atmospheric transparency window, on the other hand.
The photo and specification of the system are shown below.
Fig.1. Dual-channel laser system for DIAL
Fig.2. Mobile IR Laser system for DIAL
Fig.3. Mobile IR Laser system for DIAL (aircraft configuration)
— channel 1
3428.18 nm (2 917,0 cm-1)
|Linewidth||≤ 1,5 cm-1|
|Pulse energy||≥ 3 mJ|
|Pulse repetition rate||10 Hz|
|Pulse duration||7 nc|
|Beam diameter||5 mm|
|Divergence||≤ 5 mrad|