Photonics Dictionary: T

A waveguide having a characteristic that is altered continuously with the distance traveled, relative to the axis of its path.

The ratio between the focal length of a lens having a longer focal length than that of the standard lens used with a camera, and the focal length of the standard lens. It is used to provide an...

A coating having pigments that change color when exposed to heat. This effect has been widely used to monitor hot spots in mechanical parts.

The section of crystal symmetry having only one-quarter of the greatest number of faces permitted by the crystal system of which the section is a member.

With respect to crystals, having three mutually rectangular axes, only two of which are equal.

A display device having a thermoplastic film as the control layer medium. The film, moving from a playoff reel, is scanned by an electron gun and melted by an RF heating unit. Deformation of the film...

A laser having a material, such as ruby, that has an energy state structure of three levels: the ground state (1) wherein excitation applied to the material raises ions in the material into the...

An arc discharge tube having a grid that is used to start the discharge through an atmosphere of inert gas or vapor at low pressure.

The time domain is a concept used in signal processing and analysis to describe signals in terms of their behavior over time. In the time domain, signals are represented as functions of time, showing...

The study of the optical properties of living tissue. Increased understanding of the behavior of light in this varied, turbid medium, especially its scattering and absorption characteristics, is...

Topological photonics is a branch of physics and optics that explores the application of topological concepts to the behavior of light in photonic systems. Drawing inspiration from the field of...

A lens having one or more toric surfaces. A toric surface is one having a maximum power in one meridian and a minimum power in a perpendicular meridian. In ophthalmic optics, toric lenses are used to...

A surface that is swept out by revolving a circle about an axis that lies in the plane of the circle but that does not intersect its center. The result is a surface having different curvatures in...

The process whereby a quantum mechanical system alters from one energy level to another. During this process, energy is emitted or absorbed, and it usually takes the form of photons, phonons, or...

Pertaining to materials having the property of reflecting a part and transmitting a part of the incident radiation.

In the context of optics and lasers, a transverse mode refers to a specific spatial pattern of the electric field within the cross-section of a laser beam. These modes represent the different...

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The electrical excitation pulse occurs transversely to the optical axis...

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet that uses an electrical discharge transverse to (across) the optical axis to...

Oscillator device composed of a semiconducting diode in a coaxial resonating cavity. When the biasing current is applied to the diode, high-frequency waves are emitted into the cavity where they are...

The basis of color vision in the human eye. Three types of cones have been identified, each having a unique spectral response (red, green and blue).

With respect to a crystal, having three unequal axes intersecting at angles, only two of which can be equal and only one of which can measure 90°.

Any form of laser; e.g., a dye laser, having an output that can be adjusted over a wide range of wavelengths. Normally the range is about 70 nm wide.

Tungsten diselenide (WSe2) is a member of the transition metal dichalcogenides (TMDs) family, composed of tungsten (W) and selenium (Se). Similar to other TMDs, tungsten diselenide possesses a...

A compound crystal having two or more crystals or crystal sections that, when regularly positioned, are in reverse position relative to the other sections. When viewed, these crystals appear to be...

Twisted intramolecular charge transfer (TICT) is a phenomenon observed in certain organic molecules containing electron-donor and electron-acceptor groups that are linked together within the same...

This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and requiring a high spatial and temporal concentration of photons. The ensuing...