Light Scattering by Large Particles

In the framework of the eikonal picture, we extend the scalar description of the light scattering by large particles to a vectorial description. We first show that, under specific conditions, the expression of the components of the scattering amplitude in the framework of a vectorial description can be obtained from the scalar description of the scattering amplitude expanded in partial waves. In a second step, we show how the partial wave expansion series represents the amplitude expanded using a discrete basis while the eikonal model expands the amplitude using a continuous basis. The analogy between these two expansion series led us to assume that the relationship between the scalar and the vectorial descriptions in the framework of the eikonal picture is similar to the relationship existing in the framework of the partial waves picture. Examples show that this analogy is well founded and that the eikonal model is able to give a vectorial description of the scattering amplitude.