Photonics Dictionary: O

Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective surface appears brighter when illuminated from directly behind the...

The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical centerline for all the centers of an optical element(s) of an optical...

Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain high-resolution, cross-sectional images of biological tissues. An OCT imaging...

The physical length of the light path in a substance divided by the refractive index of that substance. See also equivalent air path.

A laser-pumped crystal with nonlinear optical properties inside of an optical resonator in which the output generates coherent light whose output can be tuned continuously over a variety of infrared...

An instrument for determining the temperature of a hot object by examining the color spectrum of the visible light it gives off and comparing it to the known temperature and wavelength spectrum of...

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and characteristics of optical components, systems, and devices. These instruments play a...

A surveying device used to measure vertical displacement of target centers of scale lines from a horizontal plane generated by up to 360° of sweep around its precision vertical axis.