All articles starting with O
9,097 articles
Optical frequency transfer
Optical frequency transfer is the distribution of a highly stable laser frequency between distant laboratories through optical fiber or free-space links, enabling comparison of optical atomic clocks.
Optical frequency-domain reflectometry
Optical frequency-domain reflectometry (OFDR) sweeps a tunable laser along optical fiber to map reflections, also measuring distributed temperature and strain with resolutions down to tens of micrometers.
Optical frequency-shift keying
Optical frequency-shift keying, or optical FSK, is a modulation format that encodes data by shifting an optical carrier between discrete frequencies, attractive because lasers can be modulated directly by drive current.
Optical Gravitational Lensing Experiment
The Optical Gravitational Lensing Experiment (OGLE) is a long-term Polish astronomical survey at Las Campanas Observatory in Chile, begun in 1992 to search for gravitational microlensing, variable stars, and transients.
Optical ground station
An optical ground station is a ground-based facility with a telescope, laser transmitters, and sensitive receivers that communicates with spacecraft using free-space laser links instead of radio frequencies.
Optical ground wire
Optical ground wire (OPGW), also called optical fiber composite overhead ground wire, is a metallic cable at the top of transmission towers that shields against lightning while carrying optical fibers, in regular use since the mid-1980s.
Optical heterodyne detection
Optical heterodyne detection combines weak received light with a local laser before photodetection, producing an electrical beat signal that carries the signal's amplitude and phase.
Optical illusion
Optical illusion, also called visual illusion: a percept that systematically differs from physical reality. Includes literal, cognitive, and physiological types such as Müller-Lyer, Ebbinghaus, and Ponzo, used to probe visual mechanisms.
Optical image stabilization
Optical image stabilization (OIS) is a camera hardware technique that moves lens elements or the image sensor to counteract hand shake, reducing blur in handheld photos and video.
Optical Imaging
Optical imaging: biomedical imaging using light interaction (scattering, absorption, fluorescence) with tissue, from microscopy to OCT, DOT, and photoacoustic methods; defined by MeSH in 2013, limited by scattering to a depth-resolution trade-off, with FDA-approved agents like ICG.
Optical injection locking
Optical injection locking is a photonics technique in which light from a master laser forces a slave laser to oscillate at the master's frequency and phase.
Optical Internetworking Forum
The Optical Internetworking Forum (OIF) is a non-profit consortium founded in 1998 by Cisco and CIENA, with over 160 members, that publishes Implementation Agreements such as 400ZR for interoperable optical networking.
Optical isolator
An optical isolator is a nonreciprocal device that transmits light in one direction while blocking reflections, protecting lasers from feedback, using the Faraday effect discovered in 1845.
Optical Kerr effect
The optical Kerr effect is the change in a material's refractive index proportional to the intensity of the light passing through it, a third-order nonlinear optical phenomenon.
Optical Kerr effect spectroscopy
Optical Kerr effect spectroscopy, also called Kerr effect spectroscopy, is an ultrafast pump-probe technique measuring transient birefringence induced by an intense pump pulse in liquids and soft materials.
Optical label switching
Optical label switching (OLS) is a packet-forwarding technique for optical networks in which a short optical label carries forwarding information, letting high-speed payloads stay optical.
Optical lattice
An optical lattice is a periodic potential for neutral atoms created by interfering laser beams, serving as the central platform for analog quantum simulation of many-body systems.
Optical lattice clock
An optical lattice clock is an atomic clock that traps many neutral atoms in a laser standing wave, achieving the lowest uncertainty of any clock, about 8.1×10⁻¹⁹ at JILA.
Optical low-coherence reflectometry
Optical low-coherence reflectometry, also known as white-light interferometry, is a technique that locates and measures reflection sites inside optical devices by interfering broadband light with a reference beam.
Optical magnetometer gyroscope
An optical magnetometer gyroscope is a rotation sensor that reads a vehicle's rotation rate from the precession of atomic nuclear spins, detected by an optically pumped magnetometer.
Optical mapping
Optical mapping, also called optical genome mapping, is a genome analysis technique that images long, labeled DNA molecules to scaffold assemblies and detect structural variants.
Optical mark recognition
Optical mark recognition (OMR), also called optical mark reading, is a technology that detects pencil or ink marks in fixed positions on forms like answer sheets.
Optical matter
Optical matter is an arrangement of microscopic particles, typically metal nanoparticles, held together by interactions from a laser light field rather than chemical bonds, self-assembling into ordered arrays under illumination.
Optical microcavity
An optical microcavity, also known as an optical microresonator, is a microscopic resonator that confines light by resonant recirculation, used in CD players, semiconductor lasers, quantum optics, biosensing, and frequency combs.
Optical microscope
An optical microscope, also called a light microscope, is an instrument that uses visible light and lenses to magnify small specimens, standard in biology, medicine, and materials laboratories.
Optical model
The optical model, or optical potential model, is a nuclear physics method describing elastic scattering by nuclei with a complex potential whose imaginary part absorbs reaction flux.
Optical module
An optical module, commonly called a pluggable optical transceiver, is a hot-swappable device that converts electrical signals to light and back for transmission over optical fiber, plugging into switches and routers.
Optical mouse
An optical mouse, also known as an optical computer mouse, tracks its movement by imaging the surface beneath it with a small camera, replacing the mechanical ball mouse.
Optical nanocavity sensing of single proteins
A label-free detection method where a single protein binding in an optical nanocavity's evanescent field shifts its resonance wavelength, allowing individual molecules to be counted in real time.
Optical neural network
An optical neural network (ONN) is a computing architecture that implements artificial neural networks with lasers, modulators, and photodetectors, performing the matrix multiplications that dominate deep learning.