Photonics Dictionary: O

The eye's involuntary reaction in the process of accommodation. This reflex is most dramatic in response to looking at a distant object after having previously been focused on a near object or vice...

An instrument used to measure backscatter as well as optical return loss and reflectance within an optical fiber system by measuring the reflected light when a continuous wave is transmitted through...

A device for measuring diffraction grating efficiency at any angle of incidence, consisting of a reflectometer wherein the detector rotates around the grating at a specific distance and is attached...

An optical time-domain reflectometer (OTDR) is a specialized instrument used in optical fiber communications to characterize and analyze the optical fibers' characteristics, including attenuation,...

A method for characterizing a fiber wherein an optical pulse is transmitted through the fiber, and the resulting light scattered and reflected to the input is measured (by an optical time-domain...

An electro-optical infrared tracker consisting of a beamsplitter, an illuminating source, an image dissector tube and an electronics unit, that automatically acquires and tracks particular eye...

Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly in applications requiring precise focusing, collimation, or imaging of...

A measurement method for reflectance by gas ionization in which light passes through a vapor before and after reflection. Detection is accomplished with a phosphor-tipped lightpipe that leads to a...

Also referred to as a funduscope, an ophthalmoscope is a specialized instrument used by ophthalmologists for observing and photographing the fundus (interior) of the eye which includes the retina,...

Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective surface appears brighter when illuminated from directly behind the...

Optical artifacts refer to undesired or unintended effects that can occur in optical systems, such as microscopes, cameras, telescopes, and other optical instruments. These artifacts can distort or...

An optical barcode reader, commonly known as a barcode scanner, is a device that uses optical technology to capture and interpret data encoded in barcode symbols. Barcodes are typically printed on...

Directing an optical beam in varying directions by varying reflection, refraction, focusing and diffraction methods.

The phenomenon that can render an optical resonator the equivalent of a semiconductor flip-flop. A bistable device will remain stable in two optical states, one of high transmission and another of...

A light absorbing material applied to ground optical surfaces during the process of making that surface non reflective. Such material should have a refractive index as high as that of the underlying...

The use of retroreflective projection technology (RPT) to project a background image onto a masked object, such as a vehicle or overcoat, thereby making the masked object appear invisible....

Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical systems. These materials are designed to provide secure and durable bonds...

Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms, to modify their reflective and transmissive properties. These coatings are...

Also known as OCT-A, optical coherence tomography angiography is an imaging technique that uses light waves to measure changes in the reflectance characteristics, enabling the the quantitative...

Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain high-resolution, cross-sectional images of biological tissues. An OCT imaging...

The storage of information via optical means, primarily employing a low-power laser to inscribe data on a photosensitive surface as pits or phase differences and to read such data via reflected light...

A rigid medium, generally a polycarbonate substrate coated with a reflective aluminum layer, that stores information (such as audio, video or data) as digital bits in the form of variations in the...

Optical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light signals over long distances with minimal loss of signal quality. It serves as a...

Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems, such as lenses, prisms, mirrors, and filters. Optical glass is...

In compact disc and CD-ROM technology, the portion of the drive that projects the laser light onto the surface of the media and picks up the resulting reflections read as data. The head includes the...

Also known as an optical diode, an optical isolator is a device that utilizes the Faraday effect to suppress or redirect backscattered or backreflected light in order to allow light transmission in...

A device used to detect and measure small amounts of rotation. The rotating object contains a reflecting surface from which a beam of light is reflected onto a positional detector. A large distance...

Optical manufacturing tools and machinery encompass a wide range of equipment, instruments, and systems used in the fabrication, shaping, finishing, and testing of optical components and systems....

Optical materials refer to substances or compounds specifically chosen for their optical properties and used in the fabrication of optical components and systems. These materials are characterized by...

1. The direct storage of data as bits in memory using optical systems and properties. The memory makes use of a laser beam that is divided by a beamsplitter and controlled by a modulator and a...

Optical strain sensors are devices that utilize optical principles to measure the deformation or strain experienced by a material under mechanical stress. These sensors convert changes in strain into...

A reflecting or refracting surface contained within an optical system.

A group of lenses, or any combination of lenses, mirrors and prisms, so constructed as to refract or reflect light to perform some definite optical function.

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and characteristics of optical components, systems, and devices. These instruments play a...

A configuration or device mounted at the end of a fiber or cable that is intended to prevent reflection.

Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter and its manifestation as both particle and wave phenomena. It encompasses the...

The area of optics that deals with the interaction of light with a given material. The optical properties of material are generally described by the absorption, transmission, reflection, and...

Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves in a material induced by the absorption of light. The term "optoacoustic"...

Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light and its interactions with different materials. The term "optoelectronics" is...

A system in which a supplied signal causes the deflection of the electron beam in a cathode-ray tube, thus forming a visible trace on the phosphor screen of the tube and providing for examination of...

Opsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well as in other light-sensitive tissues. These proteins play a crucial role in...

The partially reflective mirror at the end of the laser cavity that is the source of the beam. It controls the coupling percentage for high output power and maintains correct mode structure in the...