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Visibility and resolution of periodic structure in oblique dark‐ground illumination: Images of diatoms with rectangulate and triangulate arrays of fine structure
Author(s) -
Hewlett P. S.
Publication year - 1969
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1969.tb00683.x
Subject(s) - physics , resolution (logic) , optics , visibility , dark field microscopy , astrophysics , computer science , microscopy , artificial intelligence
SUMMARY Dark‐ground images of selected diatoms have been investigated and the resolution attained has been found compatible throughout with the Abbe theory of image formation when correctly applied. At the same time, resolution beyond that indicated by the formula conventionally quoted for dark ground is frequently possible. This is because the conventional formula is based on the imaging of a line grating, but additional diffraction maxima permitting increased resolution occur when certain other forms of periodic structure are examined under dark‐ground illumination. Some suspect claims made in the past for resolution of diatoms in dark ground are examined. Several are undoubtedly justified, though the general statement that dark‐ground resolution is equal to that in bright field is not.