Effect of an annular pupil filter on differential confocal microscopy

Combining differential confocal microscopy and an annular pupil filter, we obtained the normalized axial intensity distribution curve of an optical system. We used the sharp slopes of the axial response curve of the optical system to measure the surface profile of a reflection grating. Experimental results prove that this method can extend the axial dynamic range and improve the transverse resolution of three-dimensional profilometry by sacrificing axial resolution. (C) 2000 Optical Society of America.

Eggs of British Meniscus midges (diptera;dixidae) observed by scanning electron microscopy

The egg of Dixella martinii is described for the first time. The eggs of the Dixidae are placed in three morphological groups: bulbous and meshed; streamlined and smooth; streamlined and minutely spiculated. Ten of the fourteen species known from Britain are placed in these groups. After a detailed description of the egg of D. martinii, the three morphological groups are described and scanning electron micrographs are provided.