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The modulation contrast microscope: principles and performance
Author(s) -
Hoffman Robert
Publication year - 1977
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.1365-2818.1977.tb00033.x
Subject(s) - optics , microscope , polarizer , contrast (vision) , condenser (optics) , modulation (music) , microscopy , materials science , bright field microscopy , polarization (electrochemistry) , amplitude modulation , diffraction , physics , frequency modulation , chemistry , birefringence , computer science , computer network , light source , bandwidth (computing) , acoustics
SUMMARY The modulation contrast microscope produces an image of high contrast and resolution. The image has a three‐dimensional appearance wherein a rounded object appears dark on one side, bright on the other with grey in between against a grey background. The performance features are optical sectioning, directionality, high resolution and control of contrast and coherence. A bright field microscope is converted to the modulation contrast microscope by adding the modulator, a special amplitude filter, in the objective. A slit aperture part of which is polarized is placed before the condenser. Below this is a rotatable polarizer. The modulator processes light from opposite gradients oppositely, that is brighter for one and darker for the other; thereby preserving the sign. The diffraction theory has been extended to show that gradient image intensity is the intensity of the zero order and when modified by the modulator creates a high contrast image. The modulation contrast microscope is simple and easy to adjust. It is useful in reflected and transmitted light systems, with plastic and glass vessels as well as in combination with fluorescence systems and polarization techniques. There is virtually no limit to the type of specimen that can be studied.