Scanning optical microscopy

For a long time, observation through the microscope was carried out solely with the human eye. Photography was soon applied to the microscope, enabling documents to be preserved in memory, and cinematography gave access to the study of temporally variable phenomena. Other information has also been acquired thanks to the spectroscopic or spectrophotometric study of objects which, combined with photographic techniques, makes it possible to obtain images in a given "color", which is a means of analyzing the properties of a preparation or recognizing some of its elements.

It should therefore be noted that microscopy is a technique that users are always ready to develop in line with advances in information acquisition. For example, they have taken advantage of the possibilities offered by television, enabling both collective observation (several experimenters can simultaneously observe the same field) and the acquisition of variable information in real time (down to the frequency of the shot). But the microscopist also needs to obtain numerical information: counting particular elements previously recognized, sorting constituents of characteristic shape or given level, as well as their spatial measurements of surface, perimeter, length or distance... This type of microscopy, known as quantitative microscopy, involves identifying the points in the field by their spatial coordinates and assigning each of them a number representative of its photometric level. It is therefore necessary to capture the field point by point using a scanning technique, which is the case with television resulting from electronic scanning, to acquire the individual level by means of a photoelectric receiver, which can be the photoreceiver used in television, and to capture, by computer means, all these data which can then be processed to provide the desired information. This need for scanning has given rise to the emergence of optical techniques that enable this to be done while retaining all the resolution they allow, and even improving it significantly.

After a brief presentation of the televisual process and quantitative microscopy, this article reviews current scanning optical microscopies.

For further information on light microscopy, please refer to article R 6 712 in this section.