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- Optical_flat abstract "An optical flat is an optical-grade piece of glass lapped and polished to be extremely flat on one or both sides, usually within a few millionths of an inch (about 25 nanometres). They are used with a monochromatic light to determine the flatness of other optical surfaces by interference. When an optical flat is placed on another surface and illuminated, the light waves reflect off both the bottom surface of the flat and the surface it is resting on. This causes a phenomenon similar to thin-film interference. The reflected waves interfere, creating a pattern of interference fringes visible as light and dark bands. The spacing between the fringes is smaller where the gap is changing more rapidly, indicating a departure from flatness in one of the two surfaces, in a similar way to the contour lines on a map. A flat surface is indicated by a pattern of straight, parallel fringes with equal spacing, while other patterns indicate uneven surfaces. Two adjacent fringes indicate a difference in elevation of one-half wavelength of the light used, so by counting the fringes differences in elevation of the surface can be measured to millionths of an inch.Usually only one of the two surfaces is made optically flat to the specified tolerance, and this surface is indicated by an arrow on the edge of the glass.Optical flats are sometimes given an optical coating and used as precision mirrors for special purposes, such as in a Fabry–Pérot interferometer or laser cavity. Optical flats have uses in spectrophotometry as well.".
- Optical_flat thumbnail OpticalFlats157-03.jpg?width=300.
- Optical_flat wikiPageID "4230598".
- Optical_flat wikiPageRevisionID "604062482".
- Optical_flat hasPhotoCollection Optical_flat.
- Optical_flat subject Category:Optical_devices.
- Optical_flat type Artifact100021939.
- Optical_flat type Device103183080.
- Optical_flat type Instrumentality103575240.
- Optical_flat type Object100002684.
- Optical_flat type OpticalDevice103851341.
- Optical_flat type OpticalDevices.
- Optical_flat type PhysicalEntity100001930.
- Optical_flat type Whole100003553.
- Optical_flat comment "An optical flat is an optical-grade piece of glass lapped and polished to be extremely flat on one or both sides, usually within a few millionths of an inch (about 25 nanometres). They are used with a monochromatic light to determine the flatness of other optical surfaces by interference. When an optical flat is placed on another surface and illuminated, the light waves reflect off both the bottom surface of the flat and the surface it is resting on.".
- Optical_flat label "Optical flat".
- Optical_flat label "Planglas".
- Optical_flat sameAs Planglas.
- Optical_flat sameAs m.0br6t3.
- Optical_flat sameAs Q2098218.
- Optical_flat sameAs Q2098218.
- Optical_flat sameAs Optical_flat.
- Optical_flat wasDerivedFrom Optical_flat?oldid=604062482.
- Optical_flat depiction OpticalFlats157-03.jpg.
- Optical_flat isPrimaryTopicOf Optical_flat.
