Finite sized coherent and incoherent detectors in confocal microscopy

We consider the effects of finite sized coherent and incoherent detectors on the axial resolution of confocal microscopes. We adopt a high-angle vector approach which takes the polarization property of the object into account. We further consider polarization imaging and show that coherent detection has an advantage over incoherent detection in terms of the value of the extinction coefficient. The desirability of aberration correction is briefly discussed.