Light Propagation in a Turbulent Ocean

In addition to molecular absorption and scattering from organic and non-organic matter, light waves propagating through oceanic waters may be affected by optical turbulence, i.e., relatively mild and fast variations in the refractive index. The oceanic optical turbulence is primarily caused by fluctuations in temperature and salinity concentration and may become substantial in regions where the mechanical mixing of cold and warm (and/or fresh and salty) waters occurs. Such situations include turbulence in the ocean boundary layer during rains, around thermoclines, in the vicinity of melting ice and underground rivers flowing into open ocean waters, etc. If light waves pass through such water volumes their phase statistics and, hence, intensity statistics may become severely affected, causing scintillations, wandering, diffraction additional to that in vacuum, and changes in the state of coherence. In addition, for some beam-like waves, with specially prescribed source correlations the spectral composition and the polarization properties can also be shown to change in the oceanic turbulence in a manner different from that in vacuum. We overview in detail the recent theoretical studies on interaction of various light waves with the turbulent oceans and outline the corresponding computer simulations and experiments. We also briefly discuss some of the currently developing underwater technologies such as imagers, wireless communications, and LIDARs whose operation might be affected by the oceanic turbulence.