Photonics Dictionary

The effect in which photons are absorbed and excite the electrons; the electrons move from the valence band to the conduction band (intrinsic photoeffect), from the valence band to impurity levels or...

The creation of free electrons within a solid by the absorption of a sufficient amount of photons. The effect produces an increase in the conductivity of the solid.

Measures the refractive indices axially from the fiber profile. Microscopy technique provides an interferogram with high contrast with demonstrated improvements in relation to the Pluta two-beam...

The interaction between a photon and an energetic electron, caused by collision, that transfers energy from the electron to the photon, thus raising the energy of the photon.

The changing of the kinetic energy of a mobile electron into radiant energy, as in formation of x-rays.

The resulting contraction or expansion of a piezoelectric crystal along an electric axis when the crystal is under the influence of an electric field in the same direction.

A fusion system conductor capable of carrying current in opposite directions in alternating time phases.

Graphic representation of quantified values of image quality whose points all refer to images that are of a constant subjective quality.

Characteristic of radiation detectors that produce energy that is similar to the energy of superconductive gaps when interacting with photons.

The Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where the refractive index of a material changes in response to an applied...

A dark region created by spherical aberration of an eyepiece's exit pupil. Because of the aberration, an observer's eye must be at different distances from the eyepiece to view different regions of...

An imaging device originally created to image whole mouse brain volumes at microscopic resolution. The main component of the instrument is an automated microtome and microscope capable of producing...

An interferometer that uses a laser as its light source. The purely monochromatic nature of the laser results in improved efficiency and overall performance.

Laser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to introduce genetic material into cells. This method is a type of gene delivery...

A set of photodiodes with no gaps between them that can sense the displacement of a spot of light anywhere on the sensing area.

A lateral shearing interferometer is an optical device used in interferometry to measure phase differences between two beams of light. Interferometry is a technique that combines and analyzes...

The visual perception of contrasting forms is more difficult if the forms have the same luminance but different chromaticities, than if the forms have the same chromaticity but different luminances.

The transfer of energy lost by radiation to the body, relative to the loss of energy per unit of path traveled.

A Michelson-type interference microscope used to produce interference patterns of reflective specimens through the interference between light reflected by the specimen and that reflected by a...

In fiber optic cable, containment of the fiber or fibers within an outer protective tube in which they can move to some extent. The interstices usually are filled with an insulating material. See...

An interference microscope that uses a light beam originating from a low-coherence light source. The sample is placed in one interferometer arm, and the other arm provides a reference beam. The...

A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of light. It is named after the physicists Ludwig Mach and Ludwig Zehnder, who...

The decrease in the energy of a photoelectric emission as a result of the simultaneous incidence of radiation having lower frequency than that forming the emission.

The elimination of magnetic fields from within a material as that material makes the transition from the normal to superconducting state.

An interferometer constructed to be positioned on a telescope to measure the angular separation of the components of double stars.

A condition causing variation in output power that is eliminated by mode locking.

MTF analysis/measurement equipment refers to instruments and tools used to measure and analyze the modulation transfer function (MTF) of optical systems. The MTF is a quantitative measure of the...

Also called sine wave response and contrast transfer function. The modulation transfer function is the ratio of the modulation in the image to the modulation in the object as a function of frequency...

In physics, momentum transfer is the amount of momentum transferred from one particle to another during particle collision or interaction. This phenomenon can be utilized in various areas of physics...

Spectroscopy characterized by the Mossbauer effect - recoilless emission and absorption of nuclear gamma radiation- which investigates miniscule changes in the energy levels of atomic nuclei in...

A specific form of phase shifting interferometry - commonly referred to as multiple wavelength phase shifting interferometry - this form of interferometry utilizes two short wavelengths to synthesize...

A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path difference to create interference between split optical wavefronts. The...

A class of optical phenomena that can be viewed only with nearly monochromatic, directional beams of light, such as those produced by a laser. Harmonic generation and the stimulated Raman effect are...

Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective surface appears brighter when illuminated from directly behind the...

The relative path difference (or phase shift) traveled between two rays that pass through different mediums from the same object point. For a perfect optical system, the optical path, or distance,...

The function that characterizes the quality of an optical system by denoting the modulation and spatial phase shift of the image of a sinusoidal object with frequency as the independent variable.

See thermoelectric cooling.

A crystalline substance in which all planes are parallel, or approximately parallel.

A surface that obeys Lambert's cosine law and has a reflectance of unity.

A theoretical, ideal lens capable of producing perfect images. Used as a lens design and analysis tool to image collimated output from an afocal system.

The determination of the relative phase shift of an image as a function of frequency. A phase change of 180° with respect to the object results in an image with the black and white areas...

Generation of an acoustical signal by a sample exposed to modulated light.

The alteration of electric conductivity produced by the absorption of varying amounts of radiation composed of photons.