Ultraviolet fluorescence lidar detection of bioaerosols

A UV fluorescence lidar system for the remote detection of bioaerosols has been built and tested. At the heart of the UV- LIDAR Fluorosensor system are a 200 mJ quadrupled Nd:YAG laser at 266 nm and a 16-inch Cassagrain telescope. Operating on three data collection channels, the UV lidar is capable of real time monitoring of 266 nm elastic backscatter, the total fluorescence between 300 and 400 nm, and the dispersed fluorescence spectrum (using a small spectrograph and gated intensified CCD array). Our goal in this effort was to assess the capabilities of biofluorescence for quantitative detection and discrimination of bioaerosols. To this end, the UV-LIDAR Fluorosensor system was tested against the aerosolized bacterial spore Bacillus subtilus var. niger sp. globiggi (BG) and several likely interferences at several ranges from approximately 600 to 3000 m. Our tests with BG indicate a detection limit of approximately 500 mg/cubic meter at a range of 3000 m.