microscopy links

Koehler illumination:

http://www.microscopyu.com/tutorials/java/kohler/

Phase contrast imaging:

http://www.microscopyu.com/articles/phasecontrast/phasemicroscopy.html

http://www.microscopyu.com/articles/phasecontrast/phaseconfiguration.html

Fluorescence imaging:

http://www.microscopyu.com/articles/fluorescence/filtercubes/filterindex.html

http://www.microscopyu.com/articles/fluorescence/index.html