Elektroniemikroskopi

Elektronenmikroskopi, often shortened to EM, is a microscopy technique that uses a beam of electrons as its source of illumination. Because electrons have much shorter wavelengths than visible light, electron microscopes are capable of achieving much higher resolutions than traditional light microscopes. This allows them to visualize specimens at magnifications far beyond the limits of light microscopy, revealing details at the atomic and molecular level.

There are two primary types of electron microscopes: transmission electron microscopes (TEM) and scanning electron microscopes (SEM). In a TEM, the electron beam passes through an ultrathin specimen. The electrons that are transmitted through the specimen are then focused to form an image. This technique is ideal for studying the internal structure of cells, materials, and viruses. In contrast, an SEM scans a focused electron beam across the surface of a specimen. Secondary electrons emitted from the surface are detected and used to build up an image, which typically provides a three-dimensional view of the sample's surface topography.

Electron microscopy requires specimens to be prepared in a specific manner, often involving fixation, embedding, sectioning, and staining with heavy metals to enhance contrast. The vacuum environment necessary for electron beam operation also means that living specimens cannot generally be observed directly. Despite these sample preparation requirements, electron microscopy has become an indispensable tool in a wide range of scientific disciplines, including biology, materials science, and nanotechnology, enabling groundbreaking discoveries and advancements.