Phase fluctuations method for determining spatiotemporal distributions of the refractive-index structure parameter...

Area of Science:

• Optics and Atmospheric Science
• Physics of Fluids

Background:

• Quantifying turbulence intensity is essential for atmospheric studies.
• Direct measurement of the refractive-index structure parameter (Cn2) is challenging.
• Optical turbulence significantly impacts various applications, including remote sensing and communication.

Purpose of the Study:

• To propose and validate a novel phase fluctuation (PF) method for simultaneously determining spatiotemporal distributions of Cn2.
• To address the limitations of existing methods in directly measuring Cn2 from optical turbulence data.
• To provide a visualization tool for Cn2 and advance atmospheric turbulence research.

Main Methods:

• Development of a phase fluctuation (PF) method utilizing moiré deflectometry with double cross gratings.
• Theoretical simulations to assess the accuracy and applicability of the proposed PF method.
• Experimental validation through a one-hour measurement campaign in a real atmospheric environment.

Main Results:

• Theoretical simulations demonstrated high accuracy with relative errors of 0.5% (temporal) and 2% (spatial).
• Successful measurement of spatiotemporal distributions of Cn2 in a real atmospheric environment.
• Observed Cn2 fluctuation ranges aligned with empirical values, confirming stochastic atmospheric characteristics.

Conclusions:

• The proposed PF method offers a highly accurate and applicable approach for measuring and visualizing Cn2.
• This technique provides valuable insights into the spatiotemporal dynamics of optical turbulence.
• The study lays groundwork for future advancements in atmospheric turbulence quantification and analysis.