Photonics Dictionary

An optical wedge in which transmittance or density is a function of the location of the wedge, relative to a specific optical system.

In rangefinders and height finders, a rotatable or sliding wedge-shaped element used to divert the line of sight precisely to correct errors in the optical system.

An optical wedge of very small angles that admits light while sealing out moisture and dirt and that may be rotated to compensate for the errors in the entire system. Correction windows are sometimes...

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

The maximum variation in thickness of a lens as measured around a diameter centered on the optical axis. The ETD divided by that diameter yields the wedge of the lens.

A wedge-shaped piece of quartz typically found in a polarimeter to monitor and rotate the plane of polarization of plane polarized light. A Martens wedge can also be used in combination with other...

A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that produced by the other telescope, thus affording a measurement of the...

A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path difference to create interference between split optical wavefronts. The...

A Risley prism, also known as a Risley prism pair or Risley rotating prism, is an optical device used for controlling the direction of a laser beam or other optical beam by independently rotating two...

A circular optical wedge (prism of small refracting angle) mounted to be rotated in the path of light rays to divert the line of sight to a restricted degree.

An optical filter so constructed that the density increases progressively from one end to the other, or angularly around a circular disc.

A spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or similar device.

An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles. Wedges divert light toward their thicker portions, and may be circular,...