Photonics Dictionary: O

That surface of a lens located nearest to the eye.

A reflecting or refracting surface contained within an optical system.

The distance between the object and the cornea, or the first surface of the objective in an optical device.

The physical adaption of the eye lens, by means of ciliary muscle contraction, in order to maintain a clear, in focus image of light and other objects and surroundings at a given distance onto the...

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 polished plano-parallel plate that is contacted to an unpolished glass surface to permit see-through analysis of the material. The plate eliminates effects because of the surface quality of the...

Oleophobic is a term used to describe substances or materials that repel or resist oils. The word oleophobic comes from the Greek words "oleo," meaning oil, and "phobos," meaning fear. Oleophobic...

An opaque projector is a device used for enlarging and projecting images from opaque objects such as printed pages, photographs, or three-dimensional objects onto a screen or surface. Unlike a...

A bubble at a polished surface that has been opened by grinding or polishing.

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 assembly refers to a collection of optical components that are carefully arranged and aligned to perform a specific function within an optical system. These components may include lenses,...

The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical centerline for all the centers of an optical element(s) of an optical...

A support for optical parts comprising a solid bed that permits precise longitudinal movement of one component relative to the others, and a number of sliders equipped with holders for lenses, lamps,...

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...

A permanent, transparent, and highly transmissive adhesive capable of withstanding extreme temperatures that is applied to optical surfaces for the purpose of cementing, or the sticking together of...

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...

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 adhesion of two sufficiently clean and close-fitting surfaces without the use of cement or glue. The optically contacted surface is almost as durable as the body of the glass, and the surfaces...

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...

The amount by which an optical surface deviates from its ideal design value, expressed in wavelengths of light. Optical manufacturers use this value to determine two common characteristics of an...

A piece of glass, pyrex or quartz having one or both surfaces carefully ground and polished plano, generally flat to less than a tenth of a wavelength. Optical flats are used in surface testing to...

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...

A dome-shaped structure used for some optical instruments in place of a flat window. The transparent material should be of good quality and the hemispherical surfaces should be concentric.

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...

Also known as a white-light interferometer. Measures surface texture and shape from nanometer-scale roughness to millimeter-scale step heights. A standard arrangement includes an illumination source,...

An optical table, also known as an optical bench or an optical breadboard, is a specialized platform used in optics laboratories for mounting and aligning optical components. These tables provide a...

Refers to a variety of methods and tools used to determine the surface contour and performance of optical components and systems.

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...

Any structure having the ability to guide the flow of radiant energy along a path parallel to its axis and to contain the energy within or adjacent to its surface.

The degree to which the surface of a lens causes an incident ray of light to bend, or the amount of convergence or divergence that the surface contributes to a wavefront passing through it.

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...

In the context of imaging, particularly digital imaging and printing, "orange peel" refers to a texture or visual distortion that resembles the surface of an orange peel. This texture can result from...

The ray that has an isotropic speed and maintains a uniform polarization in all propagation directions when traveling in a doubly refracting (birefringent) crystal. It obeys Snell's law upon...

A layer of material applied to a coated surface to protect it from physical or chemical action.