In the theory of atmospheric turbulence, the strength of the spatial variations of the index of refraction n is proportional to a parameter known as the atmospheric-structure constant. The atmospheric-structure constant is denoted
and is a function of position along the optical path z. The characteristics of the temporal variations of the index of refraction are related to both
and to the transverse wind velocity V(z). Current optical techniques for remotely sensing
and V(z) rely primarily on the spatial or temporal cross-correlation properties of the intensity of the optical field. In the remote-sensing technique proposed here, we exploit the correlation properties of the wave-front slope measured from two point sources to obtain profiles of
and V(z). The two sources are arranged to give crossed optical paths. The geometry of the crossed paths and the characteristics of the wave-front slope sensor determine the achievable resolution. The signal-to-noise ratio calculations indicate the need for multiple measurements to obtain useful estimates of the desired quantities.
© 1994 Optical Society of America
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