A Self-Calibrated Laser-Induced Breakdown Spectroscopy Sensor Enables In-Flight Quantitative Elemental Analysis Onboard an Unmanned Aerial Vehicle

Quantitative atomic spectroscopy has long remained incompatible with remote elemental analysis measurement on an unmanned aerial vehicle (UAV) because it fundamentally relies on reproducible experimental conditions. Here, we introduce a self-calibrated laser-induced breakdown spectroscopy (LIBS) strategy that overcomes this limitation by retrieving both instrumental calibration and elemental quantification directly from each measured plasma emission spectrum, eliminating the need for reproducible measurement conditions, external calibration standards, and matrix-matched references. We demonstrate the approach using a compact airborne LIBS sensor integrated on a UAV, enabling quantitative stand-off elemental analysis during flight at a 3-5 m distance. The methodology is intrinsically robust against variations in laser focusing, target distance, platform motion, and environmental conditions because quantitative information is derived from the fundamental properties of the laser-induced plasma rather than from externally calibrated measurement conditions. Quantitative in-flight measurements on metallic alloys and soils demonstrate reliable elemental analysis under realistic operating conditions. The developed airborne LIBS and the proposed strategy establish a general framework for quantitative atomic spectroscopy under dynamic conditions, opening new opportunities for autonomous elemental sensing in environmental monitoring, geochemical exploration, precision agriculture, planetary exploration, and emergency response.