Inelastic hyperspectral lidar for profiling aquatic ecosystems

Monitoring the aquatic environment and the life of free-floating organisms remains on the borderline of our technical capabilities. Therefore, our insights into aquatic habitats, such as, abundance and behavior of organisms are limited. In order to improve our understanding of aquatic life, we have developed a low-cost inelastic hyperspectral lidar with unlimited focal depth and enough sensitivity and spatiotemporal resolution to detect and resolve position and behavior of individual submillimeter organisms. In this work, we demonstrate elastic as well as molecular ranging by using the water Raman band, and by observing fluorescence from chlorophyll and from dye-tagged organisms. We present an aquatic laser-diode-based inelastic light detection and ranging (lidar) system with unprecedented sensitivity, spatiotemporal resolution and number of spectral bands. Our system offers new opportunities for quantitative in situ studies of aquatic organisms, and has the potential to considerably advance our understanding of biological life in aquatic systems. (Figure presented.).