Photonics Dictionary

A set of mirrors along a telescope's polar axis designed to redirect light to a fixed position without being affected by the motion or position of the telescope. From the French word for "elbow."

The superimposition of a pilot object on each hologram. The fixed relative position of the scanning and pilot beam during the recording process ensures that sensing and fixing the pilot beam position...

FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas sample. It operates based...

Histochemical staining is a laboratory technique used in biology and medicine to visualize specific chemical components within biological tissues. This technique involves the application of various...

Often referred to as the geometric center of a given image or image plane, the centroid of an image is a fixed point located at the intersection of all of the hyperplanes of symmetry within that...

The structure that holds the photographic negative in a proper position that is both flat and parallel to the lens plane, as well as being placed in a fixed position that is the right distance from...

A device designed to measure linear or rotary motion by detection of the movement of markings on a transparent medium past a fixed point of light. The encoder has a moving code plate, a glass disc...

Positioning generally refers to the determination or identification of the location or placement of an object, person, or entity in a specific space or relative to a reference point. The term is used...

A type of compensator for use with a microscope and consisting of a quarter-wave plate in a fixed position and a rotatable analyzer.

A method used in surface quality testing for accurate positioning and rotation of metal spheres about an axis or fixed point in space that involves a sliding contact between the indicator and tip and...

A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to capture a broader field of view. Wide-angle lenses are characterized by their...

A telescope that is fixed or has a limited degree of movement in a vertical plane; primarily used to determine the position of stars near the zenith.

An optical system of variable focal length, the focal plane remaining in a fixed position. This result is achieved by moving some of the components of the system along the lens axis, other components...