Alex Clark

Date of Award


Document Type


Degree Name

Master of Science in Engineering (MSE)


Electrical Engineering

Committee Chair

Robert Lindquist

Committee Member

Patrick J. Reardon

Committee Member

Lauri L. Joiner


Refractive index., Turbulence--Measurement.


As engineers and scientists work to refine free-space optical systems that operate over long terrestrial ranges, there is a need to better understand, characterize, and quantify the atmospheric properties of the environment. One such atmospheric property of interest is the refractive-index structure coefficient, or 〖Cn〗^2, which describes small changes in the base atmospheric refractive index. Over very short distances, small index of refraction changes usually cause negligible problems to all but the most demanding optical systems, such as interferometric systems, but can have a large effect on Optical Path Length (OPL) as short as 1 km. This thesis presents a low cost, non-optical, instrument that provides accurate measures of 〖Cn〗^2 by measuring small changes in atmospheric temperature and pressure which then result in small changes to the refractive-index of air. Fabrication and testing of low cost ‘differential temperature’ sensor systems were evaluated alongside known optical atmospheric turbulence measurement devices to provide a direct comparison of the refractive-index structure coefficient with known good devices.



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