Photonics Dictionary

Also called calcite. A natural hexagonal crystal of calcium carbonate. It cleaves readily into rhomboids useful in the study of polarized light.

An instrument in which an object's image, produced by a lens of known focal length, is used to determine the object's distance from the instrument when its size is known, or the object's size if the...

A camera tube that employs a high-velocity electron beam to scan a photoemissive mosaic and to store electrical charge patterns.

Method of preserving the measured color value and color information as it is translated from differing devices. For example the output of a television display may be measured to have an identical...

The value of the distance of distinct vision, minimum focusing distance or near point, divided by the focal length of the lens. Magnification is produced when the optic is placed at its focal...

The transition cross section constant coefficient which defines the transition probability of absorption from ground to a higher level within a given atomic or molecular species. The transition...

Color correcting; chromatic aberration corrected.

A lens consisting of two or more elements, usually of crown and flint glass, that has been corrected for chromatic aberration with respect to two selected wavelengths. Also known as achromat.

Location on the CIE chromaticity diagram which produces the color white for a given light source at a specified temperature.

Cemented prisms of differing refractive indices which refract incident light and, due to differing refractive indices, will not spatially separate individual wavelengths.

The recorded interference pattern formed by the interference of two sound beams.

The optical reconstruction of image information contained in a sound field. First the diffraction pattern, formed by an object irradiated by ultrasonic rays, interferes with a mutually coherent...

The angular change of an incident beam due to vibrational induced refractive index changes within a crystal.

A system designed with a laser as a light source and a means for producing sound waves extending beyond 100 MHz to deflect light efficiently.

Light diffracted by a solid (usually quartz in crystal or fused form) traversed by acoustic waves. If the ultrasonic wavelength is larger than the diameter of the light beam, the diffraction orders...

The altering of lightwaves by acoustic waves in a solid medium.

A device that varies the amplitude and phase of a light beam; e.g., from a laser or by sound waves. Also known as a Bragg cell.

An acousto-optic modulator (AOM) is a device that utilizes the interaction between sound waves and light waves to modulate or control the intensity, frequency, phase, or direction of laser beams. It...

A bulk crystalline optic which permits the propagation of light through a volume of index altered material. The variation in refractive index along the material volume is due to a piezoelectric...

Discipline within optical physics that addresses sound vibration, phonon effects and their influencing behavior within optical elements and systems.

A thermoplastic or optically transmitting hard plastic produced by applying polymerization initiator and heat to a monomer.

Stimulating light used for the production of energy through photosynthesis, solar cell or other light senstitive device.

That point in the electromagnetic spectrum at which an optical system focuses the most chemically effective rays.

Glass designed to absorb most infrared and ultraviolet radiation while transmitting most of the visible region.

Electromagnetic energy that is capable of producing photochemical activity.

Technology that corrects the shape of reflective optics; primarily applied in large telescope systems, in order to compensate for slowly varying changes in temperature, wind and mechanical stress.

Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of atmospheric distortions. The Earth's atmosphere can cause light passing through it...

Method for studying absorption coefficients of low-loss materials, in which a sample is allowed to come to thermal equilibrium with its surrounding blackened enclosure. The sample is irradiated with...

A process during which no heat enters or leaves the system.

A chemical placed in a solution that will indicate when an excess of a substance or ion has been reached by coloring the precipitate after the chemical itself has been totally adsorbed.

An aerial reconnaissance system that can transmit, in near real time, image data recorded by IR and visual-spectrum sensors, providing day, night and foul-weather intelligence.

Also known as all-glass fiber. A fiber with both a silica core and a silica cladding, regardless of the presence of a polymer overcoat or buffer.

Left- and right-hand circularly polarized beams that are produced at different velocities by passing plane-polarized light through an optical substance. When recombined, they exhibit different phases...

A positively charged particle emitted from the nucleus of an unstable isotope, characterized by two protons and two neutrons. Quantitatively, the equivalent of a helium atom's nucleus.

A luminous display of numbers and the letters of the alphabet.

In computer graphics, a character generator that produces alphabetical and numerical characters with some punctuation and symbols.

An instrument that reads alphabetic, numerical and special characters by means of a photosensor that measures the varying intensity of the characters reflected from a light source.

A form of high-power microscope objective.

Also known as roof prism. A type of prism designed by G.B. Amici. It consists of a roof edge produced upon the long reflecting face of a right-angle prism. Used as an erecting system in elbow and...

Substances that exhibit the characteristics of both acids and bases and are capable of both P- and N-type conductivity.