Incoherent Scattering by a Distribution of Dipoles

If the particle contains a number of dipoles and the scattering is incoherent (e.g., spontaneous Raman and fluorescence) the intensity of the light at the scattered frequency emerging from the particle is the sum of the contributions from each of the dipoles. The contribution from each dipole is different because the strength and direction of the exciting field varies with the location of the dipole with the particle. Moreover, the contribution from the dielectric medium of the particle necessary to satisfy the boundary conditions also depends upon the location of each dipole. 

90° and 180° as a function of radial distance of the array of active molecules uniformly distributed over a spherical surface a = 5, mi = 1,5, 

The dashed curve represents the power of the exciting field averaged over the molecules locations 

The dependence of the radiation pattern from dipoles uniformly distributed within a spherical particle of relative refractive index m = n /n2 = 2.0 upon the particle size is illustrated in Fig.4.9 where the angular distribution in the scattered intensity is plotted in arbitrary units for different values of the size parameter. The exciting radiation incident upon the particle is assumed to be horizontally polarized. There is a sharp increase in the differential scattering 

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