Perturbation theory of super-radiance. I. Super-radiant emission

Perturbation theory is used to show that that super-radiance as envisaged by Dicke, in which the radiation rate goes as N 2 , the square of the number of atoms, can be interpreted in the same terms as classical diffraction theory. The rate goes as N 2 from samples small in three dimensions compared with a wavelength but goes essentially as N from larger samples. There is a natural distinction between coherent and incoherent contributions to the total radiation rate from larger samples prepared (supposedly by an incident pulse) in Dicke states phased with a vector k.