Photonics Dictionary: D

A telescope similar to the customary Cassegrain telescope, but having a primary mirror that is ellipsoidal and a secondary that is spherical.

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...

Design and engineering consulting services refer to professional services provided by specialized firms or individuals to assist clients in various aspects of product development, system design, or...

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 lidar (light detection and ranging) technique used in pollution monitoring. Two light beams are emitted simultaneously, one at a wavelength that will be absorbed by the target particles, and the...

Digital holographic microscopy (DHM) is an advanced imaging technique that combines holography and digital image processing to capture and reconstruct three-dimensional images of objects. This method...

A pixel-based computer graphics system that simulates the tools of an artist.

A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This digital replica is created using real-time data and simulation models, allowing...

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...

A device that provides simple and reliable laser power and energy measurement. Essentially a heat flux sensor producing an output proportional to the power, rather than the energy input.

A type of glass optical fiber that provides low pulse dispersion over a broad portion of the light spectrum and as a result can operate at 1300-nm and 1550-nm wavelengths simultaneously.

The near-point distance of the normal eye. The value of 10 in. or 25 cm is normal. This value is used in evaluating the designated magnification of a simple magnifier or eyepiece.

A device similar to distributed feedback lasers in construction and operation, but in which the period grating that produces feedback is removed from the gain region to simplify fabrication. The...

In image processing, modifying the dot that forms the image in order to simulate a series of gray tones.

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...

A device used to detect and measure the quantity of exposure to nuclear or x-ray radiation, and dependent on the fact that such radiation ionizes a gas.

In data communications, the simultaneous operation of a circuit in both directions is known as full duplex; if only one transmitter can send at a time, the system is called half duplex.

A spectroscopic technique used to display the intensity of an optical pulse as functions of time and frequency simultaneously.