Photonics Dictionary

The sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element, multiplied by the refractive index of the medium in which the vertex of the...

Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision machining tools to remove material from a workpiece. In CNC grinding, a...

The real numerical aperture (NA) of a fiber when the computed NA is not valid because of change in the glass indices during drawing and fusion.

The numerical aperture of an optical system used to couple (launch) power into an optical waveguide.

In computer graphics, a character generator that produces alphabetical and numerical characters with some punctuation and symbols.

An instrument that reads alphabetic, numerical and special characters by means of a photosensor that measures the varying intensity of the characters reflected from a light source.

The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and simulate the propagation of optical waves, particularly in the context of wave...

An instrument designed to measure the numerical aperture of an objective.

The number of molecules in one gram mole of a substance, numerically approximated by 6.02 x 1023.

Calculates the exponential growth of the least stable spatial frequency in a laser beam, and is the numerical equivalent of the nonlinear phase shift along the laser system's optical axis.

Device used to measure the numerical aperture of a microscope, composed of a 14-mm-thick glass block with numerical aperture gradations carved onto its lower surface.

The ability of the instrument to separate wavelengths that are close together, numerically equal to the ratio of the shorter wavelength to the difference between two wavelengths that can just be...

A numerical representation of the rate at which a material will exhibit dimensional changes as a direct result of changes in temperature.

A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than traditional optical techniques. CGHs are generated entirely in digital form...

A condenser that forms a hollow cone-shaped beam of light with its focal point in the plane of the specimen. If it is used with an objective having a numerical aperture lower than the minimum...

Diamond turning, also known as diamond machining or diamond cutting, is a precision machining process used to produce high-quality optical surfaces and components with extremely tight tolerances. It...

A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is specified numerically by its average diameter in 1/100 of a millimeter;...

The technique by which an analog image is converted by any of several means into a finite array of points, each represented by some numerical value. Once created, this array can be the basis of a...

A single number, defined by the computer program or the user that expresses the performance of an optical system. Also known as merit function and defect function, the error function comprises...

A numerical value representing the degree of contrast in a television picture: the exponent of the power law used to approximate the curve of output magnitude vs. input magnitude over the region of...

A two-stage illuminating system for a microscope in which the source is imaged in the aperture of the substage condenser by an auxiliary condenser, and the substage condenser in turn forms an image...

In image processing, the assigning of certain portions (or pixels) of an image a constant value of either 0 (black) or 1 (white) as to restrict image processing operations to a specific set of pixels...

The liquid used in microscopy to fill the space between the high-power objective lens and the microscope slide in order to increase the numerical aperture (NA) or collecting power in object space of...

The lens located at the object end of a microscope tube. A wide range of objectives is available, including simple achromats, the color-corrected apochromats and the flat-field objectives. Objectives...

A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are essential components in optical setups for reflecting light or redirecting laser...

Numerical scale of chroma devised by A.H. Munsell and exhibited in the Munsell Book of Color.

Numerical scale of hue devised by A.H. Munsell and exhibited in the Munsell Book of Color.

Alphanumerical description of color according to Munsell hue, value and chroma.

Numerical scale of lightness devised by A.H. Munsell and exhibited in the Munsell Book of Color.

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the symbol V, given by: where a is waveguide core radius, l is wavelength in vacuum,...

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...

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....

The condition of the numerical aperture or beam diameter of the laser, LED, or other optical source being larger than the optical fiber core or other driven source. Also called overfilled launch...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a fundamental unit that represents a single point in a raster image, which is a grid of...

The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to glass-clad fibers to reduce microbend loss and increase mechanical protection.

Factor that relates the pulse spread occurring in a graded-index fiber to that of an equivalent step-index fiber having an identical refractive index difference between core and cladding (that is, an...

The unit angle, within an arc of a circle, equal to the radius of the circle (180/p°, numerically).

RGB stands for red, green, blue, which are the primary colors of light used in additive color mixing. The RGB color model is widely used in various electronic displays, such as computer monitors,...

The technique for measuring the index profile of an optical fiber by scanning the entrance face with the vertex of a high numerical aperture cone and measuring the change in power of refracted...