2. Volume diffusion

Volume diffusion (figure 6 ) results from random fluctuations in the refractive index of media around a mean value. It can be used, for example, to visualize the trace or path of a laser beam in free space, but is better known as fog or blue sky. From an electromagnetic point of view, the calculations to be carried out are different, but under certain assumptions lead to results very similar to surface scattering. In particular, the scattered intensity is proportional to the permittivity spectrum of the scattering volume, and linear polarization modes are conserved in the plane of incidence.