Definitions

With respect to television, the returning direction of the electron beam during the vertical blanking period.

A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is established in a vertical direction with respect to the plane of the active region.

A device that measures the back focal length or vertex power of a lens.

In integrated circuits, a pathway, hole, or other passage through the substrate.

Vibrational circular dichroism (VCD) is a spectroscopic technique used to probe the chiral properties of molecules. It measures differences in the absorption of left- and right-circularly polarized...

A vibrational transition refers to a change in the vibrational energy of a molecule. Molecules consist of atoms that are connected by chemical bonds, and these atoms are not stationary but are in...

A type of change in the energy levels of molecules in a laser that results in lasing action. Vibronic transitions are those between one electronic level and another.

A test similar to the Knoop hardness test, but used for fractured material. The indenter is a square-based pyramid-shaped diamond.

Referring to the bandwidth and spectrum location of the signal produced by television or radar scanning.

A wideband amplifier used to process video or picture information.

A device, such as a thermionic or crystal diode, that is introduced into the vision channel of a television receiver to select the signal from the intermediate-frequency carrier.

A display standard no longer in use and originally defined for IBM PCs, with 640 3 480 pixels in 16 colors and a 4:3 aspect ratio. There is also a text mode with 720 3 400 pixels. The standard has...

A device that calibrates the size, position or distance of objects imaged on a video screen.

A device that changes the number of lines per frame of a video image to adapt to a lower resolution format, either by deleting lines, compressing lines or by imaging only a part of the original...

The observation of specimens by a microscope linked to a television camera and an image processor.

A disc whose surface contains recorded digital data at high-packing densities arranged in concentric rings. The data, representing video frames, are both recorded and read by a laser beam.

Videography refers to the process of capturing moving images and recording them in a digital format. It involves the use of video cameras, lighting equipment, and audio recording devices to create...

A small television tube originally developed for closed-circuit television. It is about 1 inch in diameter and 5 inches long. Its controls are relatively simple and can be operated by unskilled...

A camera that permits adjustments in the perspective of an image; this is accomplished by the camera design, which permits tilt, swing, rise or fall of the image transmitted. Also known as a...

A device, optical or electronic, that may be joined to a camera so that the operator may perceive the scene as the camera does.

A filter, pale purple in color, used in black and white photography to display the brightness values of a subject being recorded on film.

In an optical system, the gradual reduction of image illuminance as the off-axis angle increases, resulting from limitations of the clear apertures of elements within the system.

The product of the actual base or baseline of a rangefinder or heightfinder, and the power or magnification of the instrument.

Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological images and structures without the need for traditional physical slides and...

An image that is formed when rays emerging from an optical system are diverging from the optical axis. The virtual image is formed where the bundle of diverging rays appear to intersect each other...

Virtual reality (VR) is a computer-generated simulation of a three-dimensional environment or experience that can be interacted with and explored by an individual using electronic devices, such as a...

The use of miniature scanners to project raster-scanned video images directly onto the surface of the human retina, eliminating the need for a projection surface.

Having the characteristics of glass.

The transparent fluid that fills the portion of the eye between the eye lens and the retina (the posterior chamber).

A device that converts alternating voltage to direct voltage, while at the same time increasing its amplitude.

An electric cell having two electrodes of unlike metals immersed in a solution that chemically affects one or both of them, thus producing an electromotive force.

Volume Bragg gratings (VBGs) are specialized optical elements that consist of periodic variations in refractive index throughout the volume of a transparent material, typically a photosensitive glass...

Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of space. Unlike traditional two-dimensional (2D) imaging, which provides...

A vortex phase plate is an optical device designed to impart a phase singularity, commonly referred to as a vortex or phase vortex, onto a light beam. This singularity results in a phase profile...

In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a semiconducting material, usually crystalline silicon. Wafers serve as the...

1. An undulation or vibration; a form of movement by which all radiant energy of the electromagnetic spectrum is estimated to travel. 2. A type of surface defect, usually due to improper polishing.

The frequency of a wave divided by its velocity of propagation; the reciprocal of the wavelength.

An optical element having two principal axes, slow and fast, that resolve an incident polarized beam into two mutually perpendicular polarized beams. The emerging beam recombines to form a particular...

A device designed to measure the amplitude and frequency of the elements in a complex waveform.

An oscilloscope used to survey the waveform of a video signal.

A waveform is a graphical representation of the shape and magnitude of a signal over time. It typically depicts how the amplitude (strength) of the signal changes over time, with time plotted along...

For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted by virtue of the dependence of the phase and group velocities on...

A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the coupling constants of the two mode converters have a different phase relation...

A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio waves, microwaves, or light waves. It is commonly used in communication...

A device that measures the wavelength of an electromagnetic wave.