ABSTRACT
If we want to understand and model an imaging system, we have to ask what optical ˜eld (or intensity distribution/image) it will produce for a given input (object). In confocal microscopy we are interested in the quality of the focal spot. It turns out that the PSF, which is the image of a single object point (see Figure 3.1), characterizes the system completely. ”is is because the output of the optical system can be understood as the superposition of the optical ˜elds caused by the object points. In the following sections we will give expressions for the PSF of a lens. ”ese may be derived from ˜rst principles.
