Photonics Dictionary: E

Intensity distribution in the image of an edge. The gradient of the edge-response curve is a measure of the image quality of the optical system under test.

A type of optical modulator with potential application in optical switching and displays, in which applied voltage causes a change of interfacial tension between mercury and an electrolyte, varying...

A cathode-ray tube that increases the brightness or size of an image or forms a visible image from invisible radiation. The focal plane for the optical image is a large, light-sensitive, cold...

The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials. A direct recording method involves the passage of the recording medium...

A nonmagnetic instrument utilizing an electrofocus and deflection tube with a photocathode for imaging purposes. The optical image is converted into a photoelectric output at the photocathode and is...

An instrument used to print an optical image on a specially treated paper. Light and dark portions of the original image are illustrated by electrostatically charged and uncharged portions of the...

The term "embedded laser" typically refers to a laser device that is integrated or embedded into a larger system or structure. In this context, "embedded" implies that the laser is an integral part...

Enantiomers are a pair of molecules that are non-superimposable mirror images of each other, similar to left and right hands. They are stereoisomers, meaning they have the same molecular formula and...

An endoscope is a medical device used for visualizing and examining the interior of hollow organs, body cavities, or confined spaces within the body. It consists of a flexible or rigid tube equipped...

In a lens or other optical system, the image of the aperture stop as seen from object space.

An image, real or virtual, whose spatial orientation is identical to that of the object. The image obtained at the retina with the assistance of an optical system is said to be erect when the...

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...

Etaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers, interferometers, and cameras. It is characterized by the appearance of interference...

In a lens or other optical system, the image of the aperture stop as seen from image space.

Also termed eye distance. The distance between the vertex of the last optical surface of a visual optical system and the system's exit pupil.

Also known as ocular. The lens system used between the final real image in a visual optical system and eye. It acts as an image magnifier. Many types of eyepieces are known; e.g., the Huygens used in...