Abstract

The absorption coefficient is one of the most important fundamental parameters of ocean optics. It is essential for studies of light propagation and of pigment distributions. Unfortunately, its accurate measurement is severely restricted by systematic effects due to scattering. Many attempts have been made to minimize and/or correct for these effects. A new integrating cavity absorption meter that should, in fact, be rigorously independent of scattering effects is described. It involves illuminating the sample isotropically and measuring the radiation density in the cavity. The theoretical basis for this device is developed and experimental results for the absorption coefficient of water in the presence of various concentrations of scatterers are presented. These results show that, for example, at a wavelength of 633 nm, the absorption of water (0.00303 cm^-1) can be measured to an accuracy of ~1% even in the presence of suspended MgO particles at a concentration that makes the suspension look opaque.

© 1989 Optical Society of America