Photonics Dictionary

An electrically excited laser having carbon monoxide as the lasing material and in which lasing occurs in a partial inversion between adjacent, vibrational fields. Vibrational energy is cycled...

The use of a krypton laser system for the measurement of small molecules aligned by an electric field, by analyzing the absorption of linearly polarized light.

Any lamp whose emission of radiant energy is dependent upon the passage of an electrical current through the emissive medium.

A device that uses four electrodes set in an alternating positive-negative polarity series to focus the beams of charged particles employed in electron microscopes and particle accelerators.

The electric field associated with an electromagnetic wave and thus with a lightwave. The electric vector specifies the direction and amplitude of this electric field.

A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and argon lamps are examples of electric-discharge lamps.

Expression of the length of a transmission medium in terms of wavelengths of the propagating wavelength. In general, electrical length is an expression of physical length in wavelengths, radians or...

Broadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or transmit light over a broad range of wavelengths. These mirrors are constructed...

Exhibiting the characteristic of materials that are electrical insulators or in which an electric field can be sustained with a minimum dispersion of power. They exhibit nonlinear properties, such as...

A shallow, fine-pitch diffraction grating having a precise dielectric overcoating that experimentally has absorbed wavelength-specific incident light that is polarized in the P-plane.

A high-reflectance coating consisting of alternating layers of quarter-wave film of a higher refractive index and lower refractive index than the substrate. Such coatings can be made very specific to...

A number that indicates the magnitude of the shift in a solid of positive and negative charges in opposite directions when a voltage is applied across the solid.

A crystal that is characterized by its relatively poor electrical conductance.

A waveguide made up of a dielectric material, such as plastic or mica, in a cylindrical form, through which the waves travel.

A lens made up of a dielectric material that is capable of influencing radio waves much in the same way an optical lens influences light.

The ejection of electrons from the surface of a solid by the absorption of a sufficient amount of photons.

A crystal capable of being polarized in the reverse direction when an electric field is applied.

The region of a ferroelectric crystal where spontaneous polarization is uniformly directed.

Film in which electric polarization is reversible when influenced by an electric field.

Ferroelectric materials are a type of dielectric materials that exhibit spontaneous electric polarization, meaning they possess a permanent electric dipole moment even in the absence of an external...

The phenomenon whereby certain crystals exhibit spontaneous electric polarization. It is analogous with ferromagnetism.

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.

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.

State typically studied in liquid crystals in which the dielectric coefficient parallel to the director is less than the dielectric coefficient perpendicular to the director.

The effect, present in particular phosphors, that is defined as a transformation in the dielectric constant of a material when illuminated.

The transformation of incident radiant energy into a photoelectric emission current.

A cathode principally designed to emit a photoelectric current.

A system having a photoelectric detector for the measurement of three quantities related by linear combination to tristimulus values of a sample.

The measurement and analysis of color using a photoelectric instrument having three filters with broad spectrum bands.

The constant that, multiplied by the frequency of the radiation-producing emission of photoelectrons, determines the amount of voltage each photoelectron absorbs.

The control of an instrument or electrical circuit by the current produced by varying radiation incident to a photoelectric cell.

A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a photocell. Slow counting rates can be recorded by a mechanical counter, but...

The electron stream emitted by a phototube when the cathode is exposed to light.

The emission of an electron from a surface that occurs when a photon impinges upon the surface and is absorbed. This effect is the means by which photons may be detected.

The electron emission from a substance or instrument whose surface has been bombarded by a suitable amount of radiation.

A device consisting of a microammeter, a photovoltaic cell and a battery. It is used for the measurement of scene brightness and the determination of correct exposure for photographic processes.

A filter fluorometer that uses a photomultiplier tube to detect the fluorescence of a sample.

Also known as light beating. The mixing of two narrowband optical components to produce an AC component in the photocurrent at the optical difference frequency.

A phototube in which the primary photoemission current, before being extracted at the anode, is multiplied many times.

Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity of light.

The use of photoelectric sensors to detect and measure the intensity of a light source. This application, as compared to human observation, results in higher speeds of operation, a greater...

An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the intensity of the light emitted by the source.

An input device for a computer that detects and reads the data, in the form of punched holes in cards, by light that is transmitted through the holes.

An instrument that uses a photocell to detect and measure the intensity of incident light.