Degree of coherence in curvilinear coordinates and its application to scattering

In the traditional treatment of the spectral degree of coherence, the Cartesian coordinate system is deployed to describe the electromagnetic field. In the description of the far field scattered from random media, however, the spherical polar coordinates system is more suitably used due to the field's outgoing spherical form. We hence derive the expression for the spectral degree of coherence in the spherical polar coordinates system. An example of one polychromatic plane wave scattered by a collection of identical particles is given. (C) 2012 Optical Society of America