Comparative evaluation of optical turbulence and extinction instruments to high-energy laser atmospheric propagation

There are many challenges in characterizing open-air laser propagation. Varying measurement methodologies with diverse instrumentation can provide contradictory results for both optical turbulence and extinction. This paper assesses instrumentation accuracy w.r.t. a propagating laser and explores the optimal experimental setup. Accordingly, an open-air experiment was conducted to characterize the atmosphere and high-energy laser (HEL) propagation with commonly deployed instrumentation. Presented here is a comparative evaluation of the instrumentation results to far-field HEL measurements. The differential image motion monitor (DIMM) and the wide angle tele-radiometric transmissometer (WATT) provided measurements with the lowest mean percent error for optical turbulence and extinction, respectively. This suggests that path-integrated dual-sided instrumentation outperforms nodal measurements. However, it is found that nodal measurements perform best near and at the laser’s aperture height if dual-sided instrumentation is not available. Additionally, a quality-control routine is outlined for all deployed instruments considered in the evaluation. The experimental results in this paper yield instrumentation performance for characterizing static laser propagation over land. Further research is recommended to assess instrumentation over longer optical paths both static and dynamic.