Photonics Dictionary: W

A system that allows the transmission of more than one signal over a common path, by assigning each signal a different frequency band. Also known as frequency division multiplexing.

In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a semiconducting material, usually crystalline silicon. Wafers serve as the...

1. An undulation or vibration; a form of movement by which all radiant energy of the electromagnetic spectrum is estimated to travel. 2. A type of surface defect, usually due to improper polishing.

The frequency of a wave divided by its velocity of propagation; the reciprocal of the wavelength.

An optical element having two principal axes, slow and fast, that resolve an incident polarized beam into two mutually perpendicular polarized beams. The emerging beam recombines to form a particular...

A device designed to measure the amplitude and frequency of the elements in a complex waveform.

An oscilloscope used to survey the waveform of a video signal.

For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted by virtue of the dependence of the phase and group velocities on...

A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the coupling constants of the two mode converters have a different phase relation...

A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio waves, microwaves, or light waves. It is commonly used in communication...

A device that measures the wavelength of an electromagnetic wave.

A photofluorescent compound that, when used with a scintillating substance, absorbs photons and emits related photons having a greater wavelength. In this way a phototube or photocell may employ the...

A spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or similar device.

An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles. Wedges divert light toward their thicker portions, and may be circular,...

A statistical means of characterizing the failure of a fiber or device as related to strain or time. Results are plotted on a special graph paper to yield the distribution shape parameter.

A well plate, also known as a microplate or microtiter plate, is a flat plate with multiple small wells or depressions arranged in a grid pattern. Each well serves as a separate container for holding...

Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or sound waves, are trapped and circulate along the periphery of a curved...

A feature of some imaging devices, such as digital cameras, that allows them to compensate for different lighting conditions by adjusting the color balance based on the difference between a white...

The state of a carrier signal that corresponds to maximum picture brightness in a television system.

The random noise having a spectral density that is substantially independent of the frequency over a specified frequency range. White noise is widely used in the random vibration testing of devices.

The use of whiteness formulas to replace visual assessment.

Whole slide imaging (WSI), also known as virtual slide microscopy or digital pathology, is a technology that involves the digitalization of entire glass slides containing histological or cytological...

A common aberration in lenses covering large fields of view; it results in images of objects near the edge of the field being compressed in the radial distortion.

A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to capture a broader field of view. Wide-angle lenses are characterized by their...

An eyepiece or magnifier capable of covering a field of view that is greater than 50°.

Wide-field fluorescence microscopy uses either naturally occurring structures or staining with fluorescent tags that are activated by specific wavelengths of light and then emits a different...

A refractometer that has a greater resolving power than a standard refractometer, and that uses a pentagonal prism to split the light from a single slit into two beams.

Specified curved optic intended for maximum collection of light, including off-axis rays, before leaving the exit aperture.

A polarizing prism consisting of two calcite prisms cemented such that they deviate the two emerging beams (which are mutually perpendicularly polarized) by nearly equal amounts in opposite...

A grazing incidence mirror telescope with concentric conic surfaces having a single common point: a paraboloid-hyperboloid combination with two internal reflections.

The phenomenon in which alkali metals are transparent to ultraviolet radiation.

In microscopy, the clear distance between the specimen being viewed and the first optical element of the objective lens.

An optical data storage device that permits the user to store data (write) and play it back (read), but not to erase or change the stored material.

A Cassegrain telescope having a parabolic primary mirror, a spherical secondary mirror and a zero-power doublet in the converging bundle for aberration correction.