Electromicrografia

Electromicrografia refers to the creation and use of micrographs obtained with electron beams in electron microscopes. It encompasses images produced by transmission electron microscopes (TEM) and scanning electron microscopes (SEM). The technique relies on electron–matter interactions rather than visible light, offering higher resolving power and the ability to image internal structures and surface features at the nanometer to sub-nanometer scale.

In TEM, a beam of electrons is transmitted through a thin specimen, with the transmitted electrons forming an image on a detector or screen after passage through electromagnetic lenses. In SEM, a focused electron beam scans the specimen surface and detectors measure secondary or backscattered electrons to form a topographical image. Specimen preparation differs: TEM requires ultrathin sections and sometimes heavy-metal staining; SEM typically requires conductive coating and is performed on bulk samples. Both systems require vacuum and specialized detectors, cameras, and software for image capture and analysis.

Electromicrografia emerged with the development of electron optics in the 20th century and became a foundational tool in materials science, biology, geology, and nanotechnology. Improvements in resolution, contrast, and detectors, as well as the advent of cryo-fixation in TEM and fast detectors in SEM, expanded the range of observable specimens and reduced artifacts.

Common applications include imaging cellular ultrastructure, crystallographic and defect analysis in materials, morphology of nanoparticles, and inspection of semiconductor devices. Micrographs are typically published in grayscale, and digital processing is used for measurements and annotation.

Limitations include the need for complex, expensive instrumentation, vacuum requirements, potential sample damage from electron exposure, and possibility of preparation-induced artifacts. Safety concerns center on chemical stains and the handling of hazardous materials used in some preparation protocols.

See also electron microscopy, transmission electron microscopy, scanning electron microscopy, and micrography.