Photonics Dictionary

With reference to electromagnetic radiation, the number of crests of waves that pass a fixed point in a given unit of time, in light or other wave motion. Expressed in hertz or cycles per second.

A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with great accuracy. The term "frequency comb" is often associated with the Nobel...

The frequency domain is a concept used in signal processing and analysis to represent signals and data in terms of their frequency components. In contrast to the time domain, where signals are...

A nonlinear optical process in which the frequency of an optical beam is doubled coherently.

In digital data transmission, the separation of the two binary states into output at two frequencies.

A technique used in holography that involves the mixing of lasers of different wavelengths to produce a beam of shorter wavelength.

The law given by the formula: that is, the frequency of radiation emitted or absorbed by a system when E2 and E1 are the energies of the states among which transition takes place, and h is...

Relative to a light source, the frequency at which the source appears to fluctuate in light intensity half the time and remains constant during the other half.

The fusion frequency of flicker that is needed just to produce complete fusion and to assure the visual sensation of continuous illumination measured in cycles per second.

The number of times per second that the frame of a television system is completely scanned. In the United States, 30 per second is the standard frame frequency.

Distortion of the high frequencies of a signal. In television, the term generally applies to frequencies above the 15.7 kHz line frequency.

In a heterodyne optical receiver, the frequency that is the difference between that of an incoming laser signal and that of the local oscillator laser. Also called beat frequency.

Mod Method of obtaining precise temporal mode characteristics.

Rate at which optical radiation or a signal is varied through the use of a mechanical or electronic chopper. Also called chopping frequency.

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the symbol V, given by: where a is waveguide core radius, l is wavelength in vacuum,...

An optical frequency comb is a tool used for measuring frequencies with extremely high precision. It is essentially a spectrum consisting of a series of discrete, equally spaced frequency lines, much...

Number of pulses emitted per unit of time by a pulsed laser.

The frequency range for radio and television transmission.

A gas laser in which the electrodes are mounted perpendicular to the optical resonator.

A very uncommon lamp in which a tungsten electrode is heated to incandescence by a radio-frequency electrical current.

A device used to accelerate the electrons in a free-electron laser by channeling microwave energy into waveguide cavity assemblies.

With a repetitive object such as a series of equispaced lines, the reciprocal of the line spacing in object or image, generally expressed in cycles per millimeter.

The frequency band from 300 to 3000 MHz. The corresponding wavelengths are from 10 to 100 cm.

The frequency band from 30 to 300 MHz. The corresponding wavelengths are from 1 to 10 m. (VHF).

The frequency band from 3 to 30 kHz. The corresponding wavelengths are from 10 to 100 km. (VLF).

FMCW lidar stands for frequency-modulated continuous wave lidar. It is a type of lidar (light detection and ranging) technology used for remote sensing, distance measurement, and 3D mapping. FMCW...

A microcomb, short for microresonator frequency comb, is a novel photonic device that generates a precise series of evenly spaced optical frequencies, akin to the teeth of a comb, across a broad...

An absorption peak refers to a sharp increase or spike in the absorption of electromagnetic radiation at a particular wavelength or energy level. It is a distinctive feature in the absorption...

Absorption spectroscopy is a fundamental analytical technique used to study the interaction between electromagnetic radiation and matter. It involves measuring the absorption of light by a sample...

An absorption spectrum is a graphical representation of the absorption of light by a material as a function of wavelength, frequency, or energy. It displays the specific wavelengths of light that are...

An acoustic surface wave, often abbreviated as ASW, is a type of mechanical wave that travels along the surface of a material, such as a solid or a liquid, rather than propagating through its volume....

Acousto-optic deflection refers to a phenomenon where the trajectory of light is altered by acoustic waves propagating through a material. This effect is utilized in acousto-optic devices, which are...

Acoustical holography is a technique used to visualize and analyze sound fields in three-dimensional space. It involves capturing the complex spatial distribution of acoustic waves, much like how...

An acousto-optic deflector (AOD) is a type of device that utilizes the acousto-optic effect to control the direction of light beams. It operates by modulating the refractive index of an optically...

Acousto-optic diffraction refers to the process where light passing through an optically transparent material is diffracted due to the modulation of its refractive index by an acoustic wave...

Acousto-optic modulation refers to the process of using acoustic waves to modulate the properties of light passing through an optically transparent material. This modulation occurs due to the...

An acousto-optic modulator (AOM) is a device that utilizes the acousto-optic effect to modulate the amplitude, phase, frequency, or polarization of a laser beam or other coherent light source. It...

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...

An acousto-optic tunable filter (AOTF) is a device that utilizes the acousto-optic effect to selectively filter and transmit light based on its wavelength or frequency. It operates by applying an...

Acousto-optics is a branch of physics that deals with the interaction of sound waves (acoustic waves) and light waves (optical waves) within a medium. It primarily focuses on phenomena where acoustic...

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...

The advanced communication technology satellite (ACTS) was a program developed by NASA (National Aeronautics and Space Administration) in the United States to demonstrate and advance satellite...