Photonics Dictionary: F

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 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.

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 femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds, where one femtosecond is equal to 10-15 seconds. These lasers are capable of...

The law stating that the critical fusion frequency is approximately proportional to the logarithm of the luminance and the area.

The lowest frequency at which the magnitude of the fiber transfer function decreases to a specified fraction of the zero frequency value. Often, the specified value is one-half the optical power at...

A fiber optic sensor is a device that uses optical fibers to detect and measure physical, chemical, biological, or environmental parameters. Unlike traditional electrical sensors, fiber optic sensors...

The number of fields scanned per second in a television system. The US standard is 60. Also called field frequency.

Any noise with a power spectral density that is the inverse of the signal's frequency and is therefore most significant for low-frequency signals. It can be expressed as 1/f and is therefore also...

Heterochromatic photometry that depends on the elimination of chromatic flicker at a lower frequency than luminance flicker.

Fluoride fibers are optical fibers made from fluoride-based materials, typically fluoride glasses or crystalline fluoride compounds. These fibers are characterized by their unique optical properties,...

Frame rate refers to the frequency at which consecutive images, or frames, are displayed in a video sequence. It is typically measured in frames per second (fps) and determines the smoothness and...

The frequency space between consecutive transmission peaks in the transmission spectrum of a Fabry-Perot interferometer or etalon. The free-spectral range is inversely proportional to the distance...

A unit of frequency equivalent to 1012 cps. Named for Augustin Jean Fresnel, a French physicist known for his work in light and optics.