Photonics Dictionary: H

X-rays of one frequency or a narrow band of frequencies.

1. In a cathode-ray tube, the glow surrounding a bright spot that appears on the fluorescent screen as the result of the screen's light being reflected by the front and rear surfaces of the tube's...

The gray-colored tones halfway between shadows and highlights in a reproduced image.

Text or images printed on paper or another tangible medium, as opposed to those viewed electronically on a cathode-ray-tube screen.

A type of x-ray that is capable of deep penetration; its wavelength is about 10-8 cm.

A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes in a metal disc located close to the lens or mirror under test....

An optical system that superimposes a synthetic display providing navigational or weapon-aiming information on a pilot's or driver's field of view. The system includes a cathode-ray tube, collimating...

High harmonic generation (HHG) refers to a nonlinear optical process in which intense laser light interacts with a gaseous medium, typically an atom or a molecule, to produce harmonics of the...

A satellite-borne remote sensing device capable of transmitting images at 10 and 20 m resolution from an altitude of 830 km, each sensor covering a ground area of 60 km, by means of a folded...

A method of producing x-ray exposures as short as 0.03 µs; the primary application is in ballistic radiography.

A component used to modify light rays by diffraction; the HOE is produced by recording the interference pattern of two laser beams and can be used in place of lenses or prisms where diffraction...

A term applied to rays that possess the same focal point, which may be infinity, thereby meaning that the rays are parallel.

The perceptual term for that aspect of color described by words such as red, yellow or blue. Achromatic colors, such as white, gray and black, do not exhibit hue.

A device where each pixel in the detector array is mated with a preamplifier on a single silicon chip, providing sensing and signal processing capabilities.

A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide range of wavelengths within the electromagnetic spectrum, typically from...