Beam-jitter measurements of turbulent aero-optical path differences

Area of Science:

• Fluid dynamics
• Optical physics
• Aero-optics

Background:

• Aero-optical aberrations distort optical wave propagation through turbulent airflow.
• Accurate measurement of these aberrations is critical for applications like adaptive optics and remote sensing.
• Existing measurement techniques can be complex or limited in scope.

Purpose of the Study:

• To introduce a novel, non-intrusive technique for quantifying aero-optical aberrations.
• To measure the root-mean-square (rms) optical path difference power spectral density in turbulent flows.
• To validate the new technique against established methods.

Main Methods:

• Developed a technique based on angular beam-jitter measurements.
• Applied the method to an airflow with a turbulent interface and temperature discontinuity.
• Utilized a pulsed interferometer for comparative validation.

Main Results:

• Successfully obtained the rms optical path difference power spectral density using the new technique.
• Demonstrated the technique's ability to measure aberrations in a challenging airflow scenario.
• Achieved strong agreement between the new method's data and pulsed interferometer measurements.

Conclusions:

• The developed beam-jitter technique provides a viable and validated method for measuring aero-optical aberrations.
• This technique offers a new tool for characterizing optical distortions in turbulent fluid environments.
• The findings have implications for improving optical system performance in dynamic atmospheric conditions.