Photonics Dictionary: O

The system of color classification and description produced by Wilhelm Ostwald.

An otoscope is a medical device used by healthcare professionals, particularly ear, nose, and throat (ENT) specialists, primary care physicians, and pediatricians, to examine the ear canal and...

The approximate dimension of the refractive-index correlation length in a given medium.

The emission of gas or de-aeration due to thermal variations and often occurring in a vacuum. In a cleanroom, contamination from the spontaneous emission of absorbed particles.

The partially reflective mirror at the end of the laser cavity that is the source of the beam. It controls the coupling percentage for high output power and maintains correct mode structure in the...

The direct computation of the Fourier transform of the space variant system output of an optical processor with a single spherical lens. The one-dimensional output spectrum appears along a 45°...

A process for the production of optical fibers. A glass bait is rotated in a traversing flame of a reaction burner. Reactants passed through the flame react with oxygen at the high temperatures to...

The physical distance, measured along the optical axis, from the object to the image. Also called overall length.

A layer of material applied to a coated surface to protect it from physical or chemical action.

The improper exposure of a radiation-sensitive medium that results when there is too much radiation exposing the medium, or when the exposure time is too long. The resulting image, in negative form,...

The condition of the numerical aperture or beam diameter of the laser, LED, or other optical source being larger than the optical fiber core or other driven source. Also called overfilled launch...

A projector used to project transparencies. A horizontal 8 x 10-in. stage for writing or laying down preformed transparencies is provided with either an elliptical mirror or a plastic Fresnel lens...

A hologram facet illumination technique in which the illuminating beam is twice the size of the hologram facet so that full hologram resolution capability can be realized and scanning dead time is...

In a cathode-ray tube, the deflection of the beam of the tube over an angle that surpasses the angle that subtends the suitable area of the screen.

A device that uses a photoelectric cell to determine the level of oxygenation in the blood.