Particle profiling and classification by a dual-band continuous-wave lidar system

A dual-band continuous-wave (CW) light detection and ranging (lidar) system has been developed for particle classification. In this lidar system, the range-resolved atmospheric backscattering signal is recorded by an optical imaging system satisfying the Scheimpflug principle instead of the conventional time-of-flight approach. It is thus possible to employ low-cost and compact CW diode lasers, facilitating the development of a robust multiple-wavelength atmospheric lidar system that can attain high accuracy of the retrieved parameters of atmospheric particles. The present work demonstrates a dual-band Scheimpflug lidar system employing two diode lasers at 405 nm (0.5 W) and 808 nm (3.2 W). Exposures are milliseconds apart and interpolated. Measurements of various types of particles and smoke have been performed to verify the feasibility of using the present system for improved particle classification and sizing, for the situation when plumes were dilute and no significant opacity was detected.