nanophotonic

Nanophotonics is a field focused on controlling and manipulating light at nanometer scales and on integrating optical functions into nanoscale structures. It encompasses the study of light–matter interactions when materials and devices have features smaller than or comparable to the wavelength of light, enabling confinement and manipulation of optical fields beyond the diffraction limit. The field includes subareas such as plasmonics, dielectric nanophotonics, metamaterials and metasurfaces, and quantum nanophotonics.

Plasmonics uses collective electron oscillations in metals to concentrate light into features much smaller than the wavelength, producing intense local fields but with relatively high losses. Dielectric nanophotonics relies on high-refractive-index dielectrics to guide and confine light with lower losses. Metamaterials and metasurfaces are engineered assemblies that tailor phase and amplitude at the nanoscale to achieve unusual optical responses. In quantum nanophotonics, nanoscale resonators couple to quantum emitters to control emission properties and enable single-photon devices.

Typical nanophotonic devices include nanoantennas, plasmonic waveguides, photonic crystal cavities, and nanoscale lasers or single-photon sources. Fabrication combines top‑down lithography and bottom‑up synthesis, while characterization employs near-field imaging, spectroscopy, and electron-energy-loss techniques.

Applications span sensing, spectroscopy, bio-imaging, on-chip optical interconnects, and information processing, with ongoing challenges including optical losses, fabrication tolerances, and integration with existing semiconductor technologies. The field continues to push toward more efficient, compact, and functionally rich photonic systems at the nanoscale.