Photonics Dictionary

A filter used in photography to change the spectral composition of light entering a camera, or to adjust color balance during printing.

Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging light, to maintain focus.

A transducer composed of more than one high-pass, bandpass, low-pass or band-elimination filter.

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

Technique that uses high-pass filtering to reduce the local average to zero for all regions of the picture and then applies a gain factor equal to the reciprocal of the local standard deviation to...

A filter designed to improve contrast in an imaging system. For visual and black and white photosystems, a yellow filter is used.

One area of image enhancement, accomplished by spatial filtering schemes, that usually involves attenuation of phase changes in the complex amplitude over a limited region of the Fourier spectrum of...

A technique used in integrated optics where a groove is cut on a substrate surface and covered by a thin film to facilitate the construction of filters, resonators, beamsplitters and grating couplers...

A bandpass filter with piezoelectric crystal components for the passage or impedance of electrical signals of various frequencies.

A sudden, brief increase in current or voltage in a circuit that can damage sensitive components and instruments. Preventive measures include slow-starter circuits, filtering and static control.

A custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or applications. These optics can include lenses, mirrors, prisms, filters, or...

1. In detector technology, the long wavelength at which detector response falls to a set percentage (usually 20 or 50 percent). 2. In fiber optics, the shortest wavelength at which a fiber transmits...

In filter terminology, that wavelength where the filter transmission increases beyond 5 percent.

A data acquisition (DAQ) system is a combination of hardware and software used to collect, process, and analyze data from physical phenomena or processes. data acquisition system suppliers...

Data analysis software is a category of software tools used for the systematic examination of data sets to uncover patterns, trends, relationships, and insights. It supports a range of analytical...

A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively transmit or reflect certain wavelengths of light while simultaneously absorbing...

A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that selectively reflects or transmits light based on its wavelength. Dichroic...

Diffractive optical processors are optical devices that utilize diffractive optics principles to perform various computational tasks, such as image processing, pattern recognition, and optical...

A color filter that is designed to gradually increase or decrease its absorption with wavelength.

A filter purposely made to be placed before a lens to render the image rather unclear.

A linear computation or algorithm performed on a selected series in the form of an input signal that produces a new series as output. The computational device may be a specifically designed...

Digital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical quantities that vary over time or space. In the context of DSP, these signals...

A complex filter that uses polarization and interference to transmit light that is nearly monochromatic.

In image processing, any operation that strengthens information about the edges of objects displayed. Three types of spatial filtering are used: shift and difference, gradient and Laplacian.

A color filter, generally used in photography, to emphasize certain color tones and to modify others in a picture for a more dramatic image. A blue effect filter, for example, darkens red and yellow,...

An electrostatic device that uses an electric potential barrier to allow the transmittance of electrons at or above a set level of energy while stopping the passage of those below it.

When a block of glass (prism, window, filter, etc.) is placed into a converging light bundle, it increases the physical distance to the point of focus. The equivalent air path for that block of glass...

An etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance. It operates based on the principle of optical interference and is used to...

In ultraviolet and fluorescence photography, the term applied to the filter used in the photographic system and with the exciting source to screen out ambient radiations and to transmit the exciting...

A nonabsorbing, multireflecting device, similar in design to the Fabry-Perot interferometer, that serves as a multilayer, narrow-bandpass filter.

A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It consists of a periodic modulation of the refractive index along the length...

A fiber optic attenuator is a passive optical component designed to attenuate or decrease the intensity of an optical signal traveling through a fiber optic link. It achieves this by introducing a...

1. With respect to radiation, a device used to attenuate particular wavelengths or frequencies while passing others with relatively no change. 2. See digital filter.

The necessary increase of a photograph's exposure time as the result of the additional absorption of light by the filter being used.

A grating used as a reflectance filter, particularly in the far-infrared. Small plane gratings, blazed for the wavelength of the unwanted radiation, are produced for this purpose.

A function used in a convolution filtering operation. The image to be filtered is convolved with the filtering kernel to obtain the enhanced image.

A spectrophotometer that makes use of filters to isolate narrow bands of the spectrum.

A device that holds a number of filters and allows the filter with the desired characteristics to be rotated into an optical aperture.

Any of a number of instruments that uses a flame to vaporize a solution of the chemical being analyzed so that light may be passed through the vapor. Monochromation of the transmitted light is...

A filter, partially opaque to near-ultraviolet, visible and infrared radiation, that may be made by exposing and processing photographic film. Such materials are almost equally opaque to radiation of...

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 technique for measuring the concentration of any gases. Identical infrared beams are alternately chopped, one passing through a reference cell and the other passing through a cell with the gas...