M. Martinez-corral et al., Tunable axial resolution in confocal scanning microscopy by controlled symmetrical defocusing, OPT APPL, 28(3), 1998, pp. 213-225
There is presented a quite simple technique for improving the axial resolut
ion capacity of confocal scanning microscopes without detriment to their tr
ansverse resolution The technique, that is based on the equal contribution
to the image of the illuminating and collecting lenses, consists in symmetr
ical defocusing of both parts of the imaging system.