<i>In situ</i> experimental data are presented on the off-axis radiance produced by a pulsed underwater laser operating at a wavelength of 520 nm. Path lengths in homogeneous seawater range up to 50 m with separations of up to more than 6 m from the path. Absorption and scattering lengths in the water are about 6 and 4 m, respectively. These results are compared with the predictions provided by popular models derived from radiative transfer theory. Limitations are clearly shown on the accuracy of the radiance predicted by these models. The inability of the models in the small-angle approximation to predict the magnitude and shape of the radiance distributions are quantitatively shown for several experimental conditions and configurations.
© 1982 Optical Society of AmericaPDF Article