Photonics Dictionary: O

A prism or prism assembly that serves to displace the instrument's optical axis.

The electrical resistance between two points of a conductor when a constant difference of potential of one volt, applied between these points, produces in this conductor a current of one ampere, the...

A form of high-power microscope objective where the space between the object and the first element is filled with an oil having the same index as that element. This form reduces losses, increases 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 instrument for measuring opacity.

A material consisting of very small colorless particles imbedded in a clear glass matrix. It is available in two forms: flashed opal and pot opal. The flashed variety consists of a rather thin layer...

A tungsten filament lamp that uses an opal glass bulb to diffuse light.

A term describing a substance that is impervious to light; the characteristic of a substance that has no luminous transmittance.

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...

The methods and techniques used to obtain medical photographs of the human eye. To photograph the exterior of the eye, conventional still photographic equipment and procedures are used. Similarly, in...

Ophthalmology is a branch of medicine that focuses on the anatomy, physiology, and diseases of the eyes and visual system. Ophthalmologists are medical doctors who specialize in the diagnosis,...

See eye test apparatus; ophthalmic instruments.

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 fundus photography, ophthalmoscopy is the dioptrical study of the various interior components of the eye such as the macula, fovea, and opticdisk, and is overall essential in...

The capacity of a chiral substance such as a crystal or molecule to rotate the plane of polarized light that is transmitted through it. Any substance that cannot be superimposed onto it's mirror...

A measure of the optical path length for light traveling from the sun or other celestial source through Earth's atmosphere to sea-level relative to the optical path length traveled by light from the...

The mathematical evaluation of an optical system to determine and quantify its basic optical properties and image quality characteristics.

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,...

An instrument used to test lenses by utilizing the optical transfer function. It consists of a HeNe laser, a beamsplitter and two mirrors.

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...

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...

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 casting consisting of an optical material molded into the desired geometry for grinding, polishing or, in the case of optical waveguides, drawing to the final optical-mechanical specifications.

A term referring to an optical force field used to trap and stabilize particles acted upon by a force such as laser light.

An optical cable that is connector terminated. Generally, an optical cable that has been terminated by a manufacturer and is ready for installation.

A device for measuring linear dimensions. The optical caliper generally consists of two circularly mounted mirrors whose angular positions are monitored by an autocollimator, and that are capable of...

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....

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...

Transparent glassy and or crystalline structured materials engineered from inorganic, non-metallic materials via various methods that include heat or specific chemical reactions. Optical ceramics...

An optical channel monitor (OCM) is a device used in optical communication systems to monitor and analyze the performance of individual channels within a wavelength-division multiplexing (WDM)...

A photosensitive device used to optically scan and read character data (numbers, letters etc.) and input this data into a storage device. Optical character readers are based off the process of...

Optical character recognition (OCR) is a technology that is used to convert printed or handwritten text into machine-readable text. OCR software and systems are designed to recognize and extract...

A mechanical or electrical-electromagnetic device for periodically interrupting or blocking abeam of light for a brief known interval. The three most common chopper types include the tuning fork...

An optical clock is a highly precise and advanced timekeeping device that relies on the oscillations of electromagnetic radiation in the optical or ultraviolet part of the electromagnetic spectrum....

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 a non-invasive imaging technique used in medical and scientific fields to capture high-resolution, cross-sectional images of biological tissues. It provides...

An optical combiner, in the context of optics and display technologies, refers to a device or component that combines multiple optical signals or images into a single output. The purpose of an...