Coherent Back-Lasing from Atmospheric Insects

2026-07-22

I received I received the prestigious Inaba award by the lidar community for advancing lidar entomology. Our Scheimpflug lidar can be implemented at 1% of the conventional cost and weight. It allows atmospheric observation with unpreceded sensitivity and spatiotemporal resolution. The kHz sampling rates can exceed the round-trip time of the light and reveal the modulation spectra for classifying free flying insect species over ground. The method has infinite focal depth and efficiently profiles sparse organisms in the airspace with 100000 observations per day. This tool is of key importance for tackling challenges related to pollinator diversity, agricultural pests and pesticides and malaria disease vectors. As in radar entomology, in situ lidar monitoring apparently has inevitable limitations: 1) Detection limit deteriorate with range, and far observations are biased towards larger organisms, 2) It takes several wing-beats, and therefore time, beam-width and energy to retrieve a modulation spectrum for classifying species. I propose to remove range biasing and classify insects by a microsecond flash of light. Back-lasing in air has been a dream of physicists for half a century. I now intend to capture specular reflexes from flat wing membranes. When the surface normal coincides with the lidar transect, collimated back-propagating laser light is accomplished. This flash of light is spectrally fringed and can report on the membrane thickness for target classification purpose. This project has three ambitious milestones of increasing challenge with in situ campaigns: A) Polarimetric kHz lidar: Verification of specular flashes, investigation of range dependence, properties and likelihood. B) Remote nanoscopy: Spectral analysis of remotely retrieved flashes for membrane thickness assessment and optimization of back-scatter resonance. C) Farfetched flatness: I will enhance apparent surface roughness and collimated back-scatter from diffuse specimen by infrared methods

Sweden

2025-10-15