Photonics Dictionary

The film used in photographic dosimetry to record the types and amounts of ionizing radiation, such as x-rays and gamma rays, present in an area for a set interval of time. The negative produced by...

Plates of glass containing as many heavy metal oxides as can be dissolved in the glass without causing devitrification. The glass is yellow, very heavy and has a high refractive index. It is almost...

The detection and analysis of naturally formed extraterrestrial electromagnetic radiation within the radio frequency range of the spectrum.

The frequency range for radio and television transmission.

An instrument designed to collect naturally formed extraterrestrial electromagnetic radiation within the radio frequency range of the spectrum in amounts sufficient to be measured.

An instrument used to detect radioactive materials: alpha particles or helium nuclei; beta particles or free electrons; and gamma rays, which are x-rays of very short wavelength. They may be detected...

The photographic image of a thin specimen having a radioactive isotope that, formed through contact between the specimen and a photographic plate, displays the distribution of the radioactive...

A photographic process using x-ray radiation or the g-rays of radioactive materials.

The study of radioactive substances and high-energy radiations such as x-rays and g-rays.

A device used to measure the intensity of radiant energy.

Incapable of being penetrated by any form of radiation.

Capable of being penetrated by some form of radiation.

The transmission of photographic images or pictures by radio waves.

The luminescence displayed when particular minerals are irradiated with β-rays and g-rays, after being exposed to nuclear radiation.

Total number of characters available to each position of a digital numeric system.

Essentially, a hologram of a hologram, in which the first-generation hologram is masked with a narrow slit. During image reconstruction, the slit operates as the exit pupil in image space. The...

The absorption of part of the photon energy by a molecule through which there is a slight energy change and the energy balance moves on.

A flexible fiber cable with a small diameter that transports light from the excitation laser to the target. Used in Raman spectroscopy, the probe is capable of obtaining high-quality data at high...

Raman scattering, also known as the Raman effect or Raman spectroscopy, is a phenomenon in which light undergoes inelastic scattering when interacting with matter, such as molecules, crystals, or...

Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other low-frequency modes in a system. Named after the Indian physicist Sir C.V. Raman...

Essentially, noise that cannot be predicted. Therefore, even if the magnitude of sound or oscillation in a system is known at a given moment, random noise can change in a short time.

The third dimension (depth or Z-axis) in an imaging system.

1. An optical distance finder that depends on triangulation of two convergent beams on an object from disparate view points. 2. A device that depends on the measurement of time of wave travel from an...

A double meniscus system in which two achromatized meniscus lenses are arranged symmetrically on either side of the aperture stop, reducing or eliminating distortion, coma and lateral color.

Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally introduced into the crystal lattice of a material to modify its properties....

An optical fiber in which ions of a rare-earth element, such as neodymium, erbium or holmium, have been incorporated into the glass core matrix, yielding high absorption with low loss in the visible...

Rare-earth elements (REEs) are a group of seventeen chemical elements found in the Earth's crust, characterized by their unique properties and scarcity relative to other elements. Despite their name,...

In a gas, the temporary drop in density caused by contact with a sound wave.

The pattern of lines traced by rectilinear scanning in display systems.

A display in which regeneration takes place serially at a fixed speed in a set pattern through the scan lines.

Raster scanning is a technique used in imaging and scanning systems to systematically capture and process information from a two-dimensional area or surface. It involves moving a sensor or scanning...

The vertical or horizontal distance between two addressable points on a display screen; indicates the basic resolution element of a terminal.

Ratiometry is a technique used in various scientific fields, particularly in analytical chemistry and biochemistry, to measure concentrations or quantities by comparing the intensity of two different...

A geometric representation of a light path through an optical device; a line normal to the wavefront indicating the direction of radiant energy flow.

A graph of the intersections of a fan of rays with the final image plane, plotted as a function of the positions of the rays in the pupil of the system.

Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene. It involves tracing the path of rays of light as they travel through a...

When a lens system with a circular aperture is free of aberrations, the image of a point object will appear as a disc of finite size surrounded by concentric rings. When two points are separated such...

A device that is used to determine the index of refraction of a gas or liquid through the interference patterns formed by two beams of light, one of which has been transmitted by the sample. A single...

The restriction of wavefront error to within a quarter of a wavelength of a true spherical surface to assure essentially perfect image quality.

That element of a spectrum line in scattered radiation having a frequency equal to that of the corresponding incident radiation, due to ordinary or Rayleigh scattering.

A prism system designed to produce a very high dispersion of light.

In the region of a Gaussian beam focus by a diffraction-limited lens, it is the axial distance from the point of minimum beam waist (Wo) to the point where the beam diameter has increased to .

Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller than the wavelength of the light. It is named after the British scientist...