Super-Resolution Fluorescence Microscopy Using Structured Illumination

The resolution of far-field fluorescence microscopy is limited by the Abbe diffraction limit. Making use of the moir� effect, structured illumination microscopy circumvents this limit by projecting fine patterns of light into the sample. From several diffraction limited raw images taken for different pattern positions and orientations, a high resolution image can be calculated. This way, linear structured illumination can enhance the resolution by a factor of about two. Employing nonlinearities such as fluorescence saturation, the resolution can be enhanced even further. In this article, a conceptual as well as a mathematical introduction to the technique is provided, as well as several examples of applications.