Lightnear

Lightnear is a term used in photonics to describe the near-field region surrounding a light source or optical interface where electromagnetic fields are strongly evanescent and decay rapidly with distance. The concept is linked to near-field optics and contrasts with the propagating far field. In practice, definitions vary: some researchers describe lightnear as the region within approximately one wavelength (or less) from a nanoantenna, probe, or interface, while others refer to subwavelength distances on the order of tens to hundreds of nanometers for visible light.

Lightnear is central to phenomena such as evanescent waves, surface plasmon polaritons, and localized field enhancement. These effects enable interactions with matter on nanoscale length scales and can be exploited to increase spatial resolution or sensitivity beyond the diffraction limit.

Techniques and devices designed to harness lightnear include near-field scanning optical microscopy, plasmonic nanostructures and metasurfaces, optical trapping schemes, and subwavelength waveguides. Design considerations focus on geometry, material losses, and fabrication precision, since the strength and reach of the lightnear field depend strongly on these factors.

Applications and challenges: potential applications appear in high-resolution imaging, nanoscale sensing, and integrated photonics; challenges include rapid decay of the field, background noise, and the difficulty of isolating near-field signals from far-field components.

Related topics include near-field, evanescent wave, plasmonics, NSOM, and metamaterials.