optical

Optical refers to optics and the interaction of light with matter. In science and engineering, optical describes phenomena, materials, and devices that generate, transmit, detect, or manipulate electromagnetic radiation, particularly in the visible spectrum but also in infrared and ultraviolet ranges.

Light behaves as both particle and wave. The refractive index of a medium determines how light changes speed and direction at boundaries, described by Snell's law. Interference, diffraction, and polarization reveal the wave nature of light, while absorption and scattering govern what is transmitted, reflected, or converted into other forms of energy.

Common optical components include lenses, mirrors, prisms, and waveplates that shape and focus light. Imaging systems such as microscopes, telescopes, and cameras rely on precise optics. Optical fibers transmit information as light pulses for telecommunications, while lasers produce coherent light for cutting, sensing, and medical procedures. Detectors such as photodiodes and photomultiplier tubes convert light into electrical signals.

Applications span science and industry: medical imaging and ophthalmology, spectroscopy, manufacturing, and environmental sensing. Techniques such as optical coherence tomography, interferometry, and spectrometry enable high-resolution measurement. Display technologies, lighting, and optical communications are among the most widespread practical uses.

Historically, theories of light evolved from geometric optics in antiquity and medieval science to wave optics and electromagnetic theory in the 19th century, culminating in Maxwell's equations. The late 20th and early 21st centuries saw rapid advances in optics and photonics, including fiber networks, laser technologies, and quantum-optical approaches.