Effect of detector size on optical resolution in phase contrast microscopes

We examine the effects of detector size on the imaging properties of a scanning phase contrast microscope. The lateral size of the point-spread function is found to be wider when a point detector is used than when a much larger detector is used. Combining this finding with the well-known difficulties involved in using a confocal microscope in transmission mode suggests that a phase contrast microscope employing a point detector will in general have inferior imaging properties compared with one employing a large detector.