Photonics Dictionary

More efficient than the Foucault knife-edge test, this test examines curved mirrors by using a transmission grating with 40 to 200 lines per inch in place of the knife-edge, and a section or slit of...

The circle that contains the slit, grating and primary astigmatic focus of a concave diffraction grating.

The mounting of a concave diffraction grating and a plate holder at the ends of a rigid bar. The ends follow separate straight tracks that intersect perpendicular to each other. The slit is located...

An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a prism or a diffraction grating. A concave grating requires no other means...

An instrument in which an image of the sun is scanned by the entrance slit of a monochromator, the exit slit simultaneously scanning a photographic plate for analysis of the solar spectral lines. If...

An instrument similar to the spectroheliograph, but having a scanning method that is performed by a pair of rapidly oscillating slits or a rotating glass block located before a pair of fixed slits at...

A high-contrast transparency of the gas sought, or an array of exit slits that correlates with some features of the spectrum. No standardized formula for positioning, number or thickness has been...

A streak camera is a specialized instrument used to capture and analyze ultrafast phenomena, such as extremely short pulses of light or rapidly changing events. Unlike traditional cameras that...

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.