Lähidifraktsioonit

Lähidifraktsioonit, also known as near-field diffraction, is a phenomenon in optics that occurs when light interacts with objects or structures that are comparable in size to the wavelength of the light. Unlike far-field diffraction, which is observed at a distance from the object and involves the interference of light waves, near-field diffraction is characterized by the direct interaction of light with the object's surface features.

In near-field diffraction, the light waves are not fully developed into plane waves, and the interference patterns are more complex and dependent on the specific geometry and material properties of the object. This phenomenon is crucial in various fields, including microscopy, lithography, and nanophotonics, where the manipulation and control of light at the nanoscale are essential.

Near-field diffraction can be observed using specialized techniques such as near-field scanning optical microscopy (NSOM) or apertureless near-field scanning optical microscopy (ANSOM). These methods allow for the visualization of optical fields with high spatial resolution, enabling the study of light-matter interactions at the nanoscale.

The principles of near-field diffraction are also applied in the design and optimization of nanophotonic devices, such as plasmonic structures and metamaterials, which exploit the unique properties of light at the nanoscale to achieve functionalities not possible with conventional materials. Understanding and controlling near-field diffraction is therefore of significant importance in the development of advanced optical technologies and applications.