Microscopy resolving power

The classical polarizing light microscope as developed 150 years ago is still the most versatile, least expensive analytical instrument in the hands of an experienced microscopist. Its limitations in terms of resolving power, depth of field, and contrast have been reduced in the last decade, in which we have witnessed a revolution in its evolution. Video microscopy has increased contrast electronically, and thereby revealed structures never before seen. With computer enhancement, unheard of resolutions are possible. There are daily developments in the X-ray, holographic, acoustic, confocal laser scanning, and scanning tunneling micro-... 

The resolution or "resolving power" of a light microscope is usually specified as the minimum distance between two lines or points in the imaged object, at which they will be perceived as separated by the observer. The Rayleigh criterion [42] is extensively used in optical microscopy for determining the resolution of light microscopes. It imposes a resolution limit. The criterion is satisfied, when the centre of the Airy disc for the first object occurs at the first minimum of the Airy disc of the second. This minimum distance r can then be calculated by Equation (3). 

Application of models always raises the question of whether the models chosen are close enough to reality to warrant that the conclusions drawn from the model studies will be valid. Determining the shape of very small metal crystals by electron microscopy is not possible owing to the limited resolving power of the electron microscope. 

It is now possible to observe nanometer features on the surfaces of zeolitic materials using high-resolution scanning electron microscopy. By taking ibidem measurements in combination with atomic force microscopy we are able to illustrate the strengths and weaknesses of both techniques and judge respective resolving power. 

Scanning probe microscopies (SPM) such as STM and AFM are powerful tools for analyzing solid surfaces. A combination of these microscopic methods and the scattering techniques could give us a new way of determining the fine structures of microcapsule surfaces. Recently, another SPM, scanning near field microscopy, has been developed [57]. The extreme limit of the resolving power of the optical microscope based on the Abbe diffraction theorem can be raised to... 

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