Reciprocity method for obtaining the far fields generated by a source inside or near a microparticle

We show that the far fields generated by a source inside or near a microparticle can be obtained readily by using the reciprocity theorem along with the internal or near fields generated by plane-wave illumination. This method is useful for solving problems for which the scattered fields generated with plane-wave illumination have already been obtained. We illustrate the method for the case of a homogeneous sphere and then apply it to the problem of emission from a dipole inside a sphere that is near a plane interface. (C) 1997 Optical Society of America.