Photonics Dictionary: D

A Dammann grating is a type of diffractive optical element (DOE) used to create an array of equally spaced, uniform-intensity spots or beams. It is named after its inventor, Dr. Herbert Dammann. The...

The term delta error (delta-E) generally refers to the difference or change in error between two values or states. The word "delta" is often used in mathematics and science to represent a change or...

In optical communication systems, operations in which the amplitude of the pulses, as opposed to their width, determines the distance between repeaters.

A tool made by imbedding small particles of diamond in the working edge. In the optical field, the most commonly used diamond tools are glass saws, cup-shaped tools for curve generators, and diamond...

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...

Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and mirrors, from materials such as metals, plastics, and crystalline materials...

1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device designed to hold and backlight transparencies so that their images can be...

In an optical rangefinder, the system of wedges that rotate in opposite directions to aid in the detection of deviation in the image axis.

A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively transmit or reflect certain wavelengths of light while simultaneously absorbing...

A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that selectively reflects or transmits light based on its wavelength. Dichroic...

Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the direction of light propagation or polarization. The term is commonly used in...

Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical imaging technique used in microscopy to enhance the contrast of transparent...

Diffraction efficiency is a measure of how effectively a diffractive optical element (DOE) or diffraction grating directs light into specific diffraction orders or achieves a desired optical effect....

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

Diffuse reflectance spectroscopy (DRS) is a nondestructive analytical technique used to investigate the optical properties of materials, particularly in the field of spectroscopy. Unlike traditional...

An optical diffuser is an optical component or material designed to scatter or diffuse light that passes through it. It is used to create a more even or uniform illumination, reduce glare, or soften...

A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film cameras, which use photographic film to capture and store images, digital...

A diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light. Semiconductor diodes are electronic devices that conduct electricity primarily in one...

In a fiber optic transmission system, the conversion of received optical pulses directly to an electrical signal.

A write-once optical disc storage system in which the optical head reads continuously while writing to check the accuracy of the stored data. Data recorded erroneously are then rewritten at another...

A viewfinder whose optical system forms a direct image of a subject, as opposed to those systems that use reflectance in the image formation.

A hole filled with dirt such as a polishing abrasive and located in an optical surface. See dig; scratch.

A composite derived from aluminum alloy powder and silicon carbide, used as an optical substrate in air- and spacecraft applications. It is as light as aluminum but exhibits greater strength and...

Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing through a medium. This variation in the speed of light for different colors...

A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion, which is the phenomenon where different wavelengths of light travel at...

A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth light with precise control over the wavelength. It achieves this through a...

A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center than at the edges and is commonly referred to as a concave lens. The most...

An imaging process, similar to specific Doppler mapping radar techniques, that utilizes a laser, an optical imaging system, and a line array of photodetectors and spectrum analyzers. The laser...

The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such as calcite, is placed between the eye and a pinhole in a card, two bright...

Double-clad fiber (DCF) is a specialized optical fiber that features two concentric cladding layers surrounding a core. The design of double-clad fibers allows them to be used in various...

An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented together.

An optical correlator incorporating a binary phase-only spatial light modulator made from an iron garnet magneto-optic solid crystal and used in target recognition systems.