Structure function, coherence length, and angle-of-arrival variance for Gaussian beam propagation in turbulent waters.

Wave structure function, coherence length, and angle-of-arrival variance are derived analytically for a Gaussian beam propagating in an underwater turbulent medium. The recently introduced oceanic turbulence optical power spectrum model [J. Opt. Soc. Am. A37, 1614 (2020)JOAOD60740-323210.1364/JOSAA.399150] is used, and results are obtained for the case of large separations. The effect of temperature, salinity, rates of dissipation of mean-squared temperature and energy, temperature-salinity gradient ratio, wavelength, and aperture diameter, is presented. Further, a Gaussian beam is compared with the plane and spherical waves in terms of their effect on wave structure function, coherence length, and angle-of-arrival fluctuations. The presented results can be beneficial to set the parameters of imaging and communication systems using a Gaussian beam in an underwater turbulent medium and can be used for the optimization of the design of these systems.