Dark-field, Fluorescence and Confocal Microscopy

The evanescent wave condensor (Temple 1981) maximizes this principle by ensuring that the illumination occurs solely via surface waves, i.e., within the evanescent part of the electromagnetic field. Dark-field microscopy is also called ultramicroscopy since it allows one to investigate structures with characteristic dimensions smaller than the wavelength of the imaging light (visibility limit roughly A/lOO). 

As an example of contrast enhancement via dark-field illumination, bright-and dark-field images of the same object (a bent structure made of low contrast organic material) are shown in Figs 8.6a and b, respectively. As com- 

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