Elastic hyperspectral lidar for detecting coherent backscatter from insects

Sammanfattning: Insects play a major role in the ecosystem and are an important factor for biodiversity. Using laser remote sensing to distinguish and monitor the millions of insects in-situ, holds large potential to speed up and improve the otherwise time consuming process of trapping and subsequent analysis. In this work, the spectral analyser for an elastic hyper spectral lidar in the SWIR, with 64 effective spectral bands was developed, to monitor the aerofauna. The spectral analyser was designed using raytracing, CAD-desing and 3D-printing. As a proof of principle, the lidar was tested during a field campaign where the coherent backscatter of a damselfly was measured at a distance of 87 m without averaging (4 ms exposure time). From the backscattered signal, a thinfilm interference pattern could be retrieved, from which the wing membrane thickness could be determined to 1417 nm with a precision of ±4 nm. This result is very promising for future entomological studies and can bring species specificity of remote sensing of insects to a new level. Further applications of this lidar can be monitoring of gases, particles in the atmosphere and also vegetation structure.