Tomographic wavefront sensing simulations for wind tunnel measurements

Aero-optical turbulence distorts laser beams for airborne systems due to the high-speed airflow around the aircraft. The complexity of the high-speed airflow around the aircraft makes predicting and mitigating these distortions challenging. Experimentalists often use wind tunnels to collect data for aero-optical turbulence, but most wind tunnel imaging techniques are limited in their ability to capture 3D turbulence dynamics. Many standard noninvasive measurements of aero-optical turbulence, such as optical path difference, yield only 2D data and fail capture the underlying 3D nature of the turbulence. Wind tunnel seeding provides a way to capture 3D information, but it is invasive and can change the flow dynamics. While computational fluid dynamics can model 3D turbulence, it frequently fails to align with experimental test outcomes. In this paper, we propose a tomographic model-based iterative reconstruction technique that uses multiple noninvasive optical path difference measurements to reconstruct the 3D volume of wavefront aberrations in a wind tunnel. We validated our approach by reconstructing simulated volumes of atmospheric turbulence. Our simulated results indicate that our technique can accurately distinguish up to 4 layers of turbulence using a small range of viewing angles.