Lawrence Berkeley National Laboratory

Resolution is the ability to determine if a feature in an image represents two objects rather than one. Rayleigh's resolution criterion, an accepted standard in optics, was derived as a means for judging when two sources of light (stars) were distinguishable from a single source. In microscopy, resolution is the ability to determine if detail in an image represents distinct (separated) objects. In high-resolution TEM, these objects are atoms. Resolution of bar d bar is achieved when atoms separated by a (projected) distance bar di bar can be perceived as separate objects. TEM images are able to depict projected atom columns because they are interference patterns of the directly transmitted electron beam with beams diffracted from the specimen imaged under well-established conditions.