High-sensitivity DIAL measurements with spectrally coherent infrared lasers

摘要

Our scenario/measurement analysis to data shows that coherent CO_2 lasers are suitable for long range sensing of absorbing effluents from airborne platforms. The concepts can be extended to satellite band systems. We have specifically shown that high sensitivity can be retained by speckle averaging with a pulse burst imaging type waveform. TSC has determined that: 1. Frequency agile mode-locked 2-4 μsec coherent pulse burst waveforms will be suitable for speckle averaged remote sensing of weak absorbers at ranges which are substantially larger than those obtainable for direct detection measurement procedures. 2. A few pulses using frequency agile coherent 2-4 μsec pulse-tone waveform will provide maximum (photon starved) range performance when the absorption is strong. 3. Data obtained have been published and have verified the basic speckle averaging predictions.