Theory for confocal and conventional microscopes imaging small dielectric scatterers

In this paper we develop the theory of confocal microscopes imaging small scatterers. Since scattering is a polarization dependent phenomenon we employ a full vectorial theory to treat this problem. This approach permits us to consider both imaging in high aperture systems as well as image formation in polarized light microscopy. We extend previous theories by including effects of the finite sized detector apertures. Numerical examples are presented for the most important cases. The results of the full vectorial theory are compared with those obtained from low aperture paraxial theory.