The role of specimen‐induced spherical aberration in confocal microscopy

We present an overview of recent theories for describing specimen‐induced spherical aberration in confocal microscopy. One of these theories is used to compute numerically the role of spherical aberration in general confocal, and especially in biological confocal, microscopy for a variety of three‐layer specimen structures. In particular, we study the effect of specimen‐induced spherical aberration on the maximum value of the overall confocal point spread function, the accompanying focal shift and the size of the optical probe in both fluorescence and brightfield confocal microscopy.