photonics

Photonics is the branch of science and engineering that studies and applies the generation, control, transport, detection, and utilization of light, especially in the visible and near-infrared spectrum. It seeks to exploit photons as information carriers and energy carriers across a range of wavelengths and temperatures. While optics covers the behavior of light, photonics emphasizes the design of systems and devices that actively manipulate light for practical purposes, including communication, imaging, sensing, and power conversion.

Key components include light sources such as lasers and light-emitting diodes, passive and active optical elements such as waveguides and optical fibers, photonic integrated circuits, modulators and switches, and detectors such as photodiodes and image sensors. Core physical concepts involve interference, diffraction, polarization, nonlinear optics, and quantum phenomena that enable phenomena like entanglement and single-photon operations.

Materials and platforms span silica-based fibers and glasses, silicon and III-V semiconductors for sources and detectors, lithium niobate and other electro-optic materials, and emerging nonlinear or chalcogenide media. Photonics also encompasses fields such as nanophotonics, plasmonics, metamaterials, quantum photonics, and biophotonics, often bridging physics, engineering and chemistry.

Applications are broad: fiber-optic communications and data networks; medical imaging and therapy (for example, optical coherence tomography); sensing and environmental monitoring; manufacturing, metrology and energy harvesting; and defense or autonomous systems, including LIDAR. Ongoing research focuses on miniaturization, integration, higher efficiency, quantum information processing, and new materials.