Structured illumination microscopy

Illuminating a sample with “structured” light allows a conventional
full-field microscope to achieve resolutions of about 50 nm. (a) A
structured object (i.e. the sample), which is too fine to be imaged by
the microscope, is illuminated by light in a different pattern (b). The
resulting emission from the fluorophores is then the product of these
two patterns (c), but what the microscope sees is a set of low-resolution
Moiré fringes (d). These fringes contain information from the
original sample, and a series of three structured images taken at
different orientations and some simple maths allows a high-resolution
image of the original pattern to be reconstructed.