Definitions

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 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.

A device that measures the wavelength of an electromagnetic wave.

A beamsplitting mirror that reflects as a function of wavelength.

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...

Electromagnetic energy is transmitted in the form of a sinusoidal wave. The wavelength is the physical distance covered by one cycle of this wave; it is inversely proportional to frequency.

A method of specifying the allowable edge-thickness difference or decentering of a lens.

The Weissenberg method, named after the German physicist Karl Weissenberg, is a technique used in x-ray crystallography for obtaining high-quality diffraction patterns from single crystals. This...

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 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.

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...

The formula that gives the wavelength of maximum spectral radiant emittance of a perfect blackbody: λmax = 2898/T(µm) The radiation at this λmax can be calculated as follows:...

The maximum aperture of a lens at which it will still give a sharp image, even though its physical aperture may be larger.

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

The series of processes used to identify and evaluate crystal structure by using crystalline solids to diffract x-rays. In the Laue method, radiation of a wide range of wavelengths is transmitted by...

An instrument that measures the wavelengths of an x-ray spectrum by the diffraction of x-rays from a crystal with a given lattice spacing.

The penetrating capacity of x-rays that is an inverse function of the wavelength.

An image intensifier that consists of an evacuated tube with a large input phosphor screen at one end. The phosphor screen is in contact with a light-sensitive photocathode that emits electrons....

A method of projecting integrated circuit patterns on a silicon wafer using x-ray wavelengths focused through a special mask.

An instrument for eye surgery that directs intense xenon arc light through the transparent cornea lens to the retina where absorption by the pigment epithelium and the choroid produces heat and...

Fluid used to aid in examination of semifinished blanks.

A YAG crystal refers to a solid-state crystal made of yttrium aluminum garnet (YAG), which is a synthetic crystalline material. YAG crystals are known for their exceptional optical properties,...

In a single-mode optical fiber, the wavelength that causes material dispersion and waveguide dispersion to cancel each other. In a multimode fiber, loose term for the wavelength at which there is a...

A grating that specularly reflects the specified long radiation wavelengths and diffracts the shorter wavelengths off in known directions, eliminating the interference of randomly scattered radiation.

A quarter- or half-wave retarder made from two plates of quartz, mica or polymer with their fast axes crossed; the difference in thickness between the two plates determines the retardance. Zero-order...

A polyethylene grating that transmits the long wavelengths and diffracts shorter wavelengths in controlled directions.

Zerodur is a type of glass ceramic material known for its exceptional thermal and mechanical properties, particularly its low coefficient of thermal expansion (CTE) close to zero. It was developed by...

Spherical or chromatic aberration in a lens having a wide aperture. It is present because the refracting power varies for different zones concentric at the axis. This is the residual when the lens...

A plate of glass, usually a photograph, on which there is a central spot surrounded by concentric annular zones, alternately opaque and transparent, the radii of the boundaries between the zones...