Dictionary » P » Phase-amplitude contrast

Phase-amplitude contrast

phase-amplitude contrast

(Science: microscopy) The separation and recombination of direct vs. Diffracted rays in a light microscope adjusted to kohler illumination. at the lower focal plane of the condenser there is an annular diaphragm with an opaque central stop. Through this diaphragm rays are focused as a hollow cone onto the specimen. In the back focal plane of the objective there is a conjugate annular diaphragm (phase plate). If here the undiffracted rays are retarded (by a transparent film of proper thickness on the annulus of the phase plate), bright contrast results. If, instead, the phase-delay film is on the central spot, dark contrast results. With either a bright or a dark-contrast phase plate, the annulus is usually coated with a partially absorbing (very thin) film of silver (Zernike method) or carbon soot (Wilska method) to reduce the higher amplitude (intensity) of the undiffracted rays.

Please contribute to this project, if you have more information about this term feel free to edit this page

Results from our forum

Please help me decide which microscope to buy

... at unstained cells, some special beam arrangements should be there - phase contrast, dark field, something...

See entire post
by Darby
Wed Nov 06, 2013 6:42 pm
Forum: General Discussion
Topic: Please help me decide which microscope to buy
Replies: 2
Views: 2774

Extra Light For Compound Light Microscope ???

... me everything about this microscope ... ) tell me about dark field , phase contrast microscopes also :) thx in advance .........

See entire post
by Kehsibashok
Sun Jul 28, 2013 6:12 am
Forum: Cell Biology
Topic: Extra Light For Compound Light Microscope ???
Replies: 1
Views: 2031


... I need information about these topics: 1-Fluorescence microscop. 2-Phase-contrast microscope. 3-Differential-interferance-contrast (Normaski) microscope. 4-confocal ...

See entire post
by pharma623
Sat Nov 05, 2011 8:34 am
Forum: General Discussion
Topic: help....?!!!!
Replies: 2
Views: 796

Alternation of generation

... haploid organism, each giving rise to the other. This is in contrast to animals, in which the only multicellular phase is the diploid organism (such as the human man or woman), whereas the haploid phase is ...

See entire post
by kika
Tue Aug 02, 2011 10:36 am
Forum: Botany Discussion
Topic: Alternation of generation
Replies: 8
Views: 18276

sporulation in Bacillus

... trying to count the sporulation efficiency in my B.pumilus mutants by phase contrast microscopy as well with counting on normal LB agar plate ( after heat shock at 80deg ...

See entire post
by praveen127
Thu Oct 07, 2010 3:08 pm
Forum: Microbiology
Topic: sporulation in Bacillus
Replies: 1
Views: 1983
View all matching forum results

This page was last modified 21:16, 3 October 2005. This page has been accessed 2,200 times. 
What links here | Related changes | Permanent link