... the sample comes through both objective lenses,[9] and thus its theoretical optical properties are identical to that of type-A 4Pi [10]. In10 I. Optical Microscopy, Scanning Probe Microscopy, ... be 130 nm for type-A (and thus for the optically equivalent type-B) and 95 nm for type-C, andmeasured at 140 nm and 95 nm, respectively [10]. The width of the central peak isindependent of ... functions for various types of microscopes. (a) ideal imaging system, with adeltafunction at z =0. (b) typical confocal microscope, with a gaussian profile. (c) 4Pi-A microscope.(d) 4Pi-C microscope....