Absorption, scattering, and optical turbulence in natural waters

Abstract

The Beer–Lambert–Bouguer law characterizes attenuation of an optical plane wave resolved in terms of absorption and scattering of a medium it passes through. However, the optical turbulence present in a medium may also cause severe local attenuation in beam-like light fields. This study aims to incorporate the effects of absorption and scattering with that of optical turbulence in Earth’s natural waters. To do so, expression for the turbulence induced local attenuation coefficient is developed first for the on-axis position of the lowest-order Gaussian beam, being dependent on the source’s wavelength, width, and propagation distance. We present a comparison among turbulence, absorption, and scattering effects for different Jerlov water types. Our results show that underwater turbulence can cause attenuation quantitatively comparable to that of absorption. This study enables a direct comparison of absorption, scattering, and turbulence effects and will benefit the diagnostics of imaging, sensing, and communication systems operating underwater.