Researchers have developed an atmospheric sensing method using structured terahertz beams carrying orbital angular momentum to detect clear-air turbulence, according to a study published in Nature Communications. Clear-air turbulence evades conventional weather radar and continues to pose hazards to aviation.
Existing optical detection techniques falter under severe turbulence and remain vulnerable to misalignment between airborne nodes. The proposed terahertz orbital angular momentum (THz-OAM) scheme addresses those constraints. In simulations and experiments, the THz-OAM system remained functional under severe turbulence conditions that saturate optical systems, while demonstrating orders-of-magnitude greater resilience to angular misalignment.
The researchers derived and experimentally validated an analytical model linking turbulence-induced OAM modal crosstalk to the refractive index structure constant of the atmosphere. By tracking how diverging THz-OAM beams interact with the medium across reciprocal propagation paths, the scheme localizes dominant turbulent clusters. The setup also monitors atmospheric water vapor simultaneously to identify turbulence precursors.
Ruiyi Shen and Yasaman Ghasempour of Princeton University authored the study with M. van Iersel, with Ghasempour also affiliated with New Mexico State University. Research support came from the US Air Force Office of Scientific Research under grants FA9550-24-1-0144 and FA9550-24-1-0359. The peer-reviewed study was submitted on December 10, 2025, accepted on August 4, 2026, and published on August 15, 2026.
