Photonics Dictionary

In analysis, a reference spectrum, having predetermined wavelengths, that is used to determine the wavelengths of another spectrum through comparison of the two.

A microscope eyepiece designed for use with apochromatic objectives. Since apochromatic objectives are undercorrected for lateral color, these eyepieces are overcorrected for that aberration.

Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging light, to maintain focus.

Complementary metal-oxide-semiconductor (CMOS) refers to a technology used in the fabrication of integrated circuits, particularly semiconductor devices like microprocessors, memory chips, and image...

1. A constituent part. It may consist of two or more parts cemented together, or with near and approximately matching surfaces. 2. The projection of a vector on a certain coordinate axis or along a...

A lens composed of two or more separate elements of optical glass that may or may not be cemented together. The surfaces of the elements are shaped to reduce or eliminate the aberrations inherent in...

A method of producing large volumes of plastic optical components in which powdered or sheet plastic is pressed between heated dies.

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The great advantage of this grating lies in the fact that no separate collimating...

The generation of a grating on a concave spherical blank by the holographic process. In this way, ghost images and intense stray light are avoided.

Characterized by having the same center. Concentric circles differ in radius but have a common center point.

A lens having surfaces whose centers of curvature coincide.

The distance between the center of the two concentric circles of an optical fiber that designate the diameter of the cladding and the center of the two concentric circles that designate the diameter...

A single positive lens or group of lenses used in a projection system to collect light from a source and cause it to illuminate evenly the object to be projected.

A material property that is the inverse of its resistance to the flow of electricity.

A partially filled or empty energy band through which electrons can move easily. The material can therefore carry an electric current. The term is usually applied to semiconductors.

A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed by the material through conduction and melts the material to produce an edge...

1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from or converging upon a point are sometimes referred to as a cone of light. 2....

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

A microscope design that involves apertures inserted in conjugate plane positions inside the microscope, with one aperture in front of the illumination source and the other at the focal position in...

The dispersion of a light ray striking the surface of a biaxial crystal, in which the resulting rays are reflected in a conical manner.

A parabolic, elliptical, hyperbolic or circular section created when a solid cone is intersected by a plane.

A lens with a surface that is a cone instead of the usual sphere.

A device used to determine the location and attitude with respect to the Earth of orbiting spacecraft by detecting the difference in thermal radiance between the Earth's horizon and space.

A connectome refers to a comprehensive map or diagram of neural connections within the brain or nervous system of an organism. It encompasses all the intricate pathways formed by neurons, including...

Hardware installed on fiber cable ends to provide cable attachment to a transmitter, receiver or other cable. Usually a device that can be connected and disconnected repeatedly.

Energy loss encountered at connectors in optical fiber transmission systems. The major contributors are mutual core displacement and fiber axis tilt. It is observed in both permanent splices and...

An optical instrument, generally a polarizing microscope, that is used to determine the interference figures and optical axis of a sample crystal. Also called a hodoscope.

The principle that states that optical instrumentation cannot increase the radiance of a source; the radiance of an image cannot exceed that of the object.

That property of certain optical devices, e.g., a penta prism, that maintains the angular relationship between the entering and the emerging rays traversing the system regardless of the orientation...

Method of disk rotation used for optical disk drives, in which the spindle motor decreases the speed of the disk's rotation as the head moves from the inner tracks to the outer, so that the radial...

A device used in broadcast CCD cameras to improve definition in heavily saturated colors by band-limiting the color difference signals after gamma correction.

Technique that uses high-pass filtering to reduce the local average to zero for all regions of the picture and then applies a gain factor equal to the reciprocal of the local standard deviation to...

Reciprocal of the dispersive power of an optical material. See Abbe constant.

A liquid, usually of a specific refractive index and dispersion, serving as an interface between two solids to form a complete light transmission system.

Laser surgery by means of a low-power laser system using a synthetic sapphire scalpel that transmits the laser light while in direct contact with the tissue.

The radiation spectrum of matter found in condensed states, liquid or solid, that is continuous and not a line spectrum. The details of this spectrum are almost independent of the matter emitting the...

Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In various contexts, the term is used to describe continuous, uninterrupted...

A method in optical character recognition in which a mobile light beam scans the outlines of characters for subsequent reading of these outlines.