transmissionsmikroskopia

Transmissionsmikroskopia is a group of imaging techniques that produce an image by transmitting a beam through a sample. The detected transmitted signal carries information about the sample’s structure, composition, and interactions with the beam. Contrast arises from absorption, scattering, or phase shifts introduced by the material being examined. The technique generally requires the sample to be sufficiently thin or transparent for the chosen beam.

Optical transmission microscopy, or transmitted-light microscopy, uses visible or near-infrared light. Contrast relies on differences in absorption and refractive index, often enhanced by staining or labeling. Samples are typically thin sections mounted on slides, and resolution is limited by the wavelength of light. This method is widely used in biology, medicine, and materials science for routine inspection and qualitative analysis.

Transmission electron microscopy (TEM) employs a beam of electrons and achieves far higher resolution because electrons have much shorter wavelengths. In TEM, samples are prepared as ultrathin sections or as prepared specimens embedded and sectioned for durability under vacuum. Contrast is influenced by electron scattering and staining with heavy metals. Imaging modes include bright-field, dark-field, and diffraction. Preparation is more complex and can introduce artifacts, but TEM reveals fine ultrastructural detail.

Other related forms include scanning transmission electron microscopy (STEM), which combines scanning principles with TEM imaging. Applications span cellular ultrastructure, crystallography, defect analysis, and materials characterization. Limitations include sample thickness constraints for optical transmission and potential radiation damage for electron-based methods.