ABSTRACT
This chapter considers electromagnetic diffraction from cavity structures that contain dielectric obstacles. It also considers spherical shell cavities with spherically symmetric dielectric inclusions. The chapter is concerned the resonant heating of bodies with absorbing properties; thus, instead of the scattered field, the quantity of greatest interest is the electromagnetic energy coupled to the cavity region. It discusses homogeneous dielectric spheres and multi-layer structures consisting of homogeneous dielectric shells. The resonant excitation of an open spherical cavity provides an alternative mechanism for heating small objects. In contrast to the laser, a single mode is generated in the cavity. The chapter utilizes the mathematical treatment of a spherical cavity filled with dielectric material has much in common with the approach for the empty cavity. It is of interest to determine accurately the distribution of the electromagnetic energy density around dielectric spheres of varying electrical size, with attention to the formation of well defined focal regions or spots.
