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Encyclopedia > Nicol prism
A Nicol prism
A Nicol prism

A Nicol prism is an optical device used to generate a beam of polarized light. Image File history File links A Nicol prism. ... Image File history File links A Nicol prism. ... This article treats polarization in electrodynamics. ...

It was invented in 1828 by William Nicol (1768-1851) of Edinburgh. It consists of a rhombohedral crystal of calcite (Iceland spar) that has been cut at a 68° angle, split diagonally, and then joined again using Canada balsam. 1828 was a leap year starting on Tuesday (see link for calendar). ... William Nicol (1770 - 1851), Scottish physicist and geologist who invented the first device for obtaining plane-polarized light - the Nicol prism - in 1828. ... 1768 was a leap year starting on Friday (see link for calendar). ... 1851 was a common year starting on Wednesday (see link for calendar). ... Edinburghs location in Scotland Edinburgh viewed from Arthurs Seat. ... In crystallography, the rhombohedral (or trigonal) crystal system is one of the 7 lattice point groups. ... Calcite from Brushy Creek Mine, Missouri, USA. The mineral calcite is a calcium carbonate corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earths surface. ... Canada balsam, also called canada turpentine or balsam of fir, is a turpentine which is made from the resin of the balsam fir. ...

Unpolarized light enters one end of the crystal and is split into two polarized rays by birefringence. One of these rays (the ordinary or o-ray) experiences a refractive index of no = 1.658 and at the balsam layer (refractive index n = 1.55) undergoes total internal reflection at the interface, and is reflected to the side of the prism. The other ray (the extraordinary or e-ray) experiences a lower refractive index (no = 1.486), is not reflected at the interface, and leaves through the second half of the prism as plane polarized light. A calcite crystal laid upon a paper with some letters showing the double refraction Birefringence, or double refraction, is the division of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals, depending on... The refractive index of a material is the factor by which the phase velocity of electromagnetic radiation is slowed relative to vacuum. ... The larger the angle to the normal, the smaller is the fraction of light transmitted, until the angle when total internal reflection occurs. ... This article needs a complete rewrite for the reasons listed on the talk page. ...

Nicol prisms are used in polarimeters and microscopes. A polarimeter is a scientific instrument for measuring the rotation of the plane of polarized light as it passes through a sample of a compound which exhibits optical activity. ... 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ...

  Results from FactBites:
Olympus Microscopy Resource Center: Physics of Light and Color - Introduction to Prisms and Beamsplitters (5074 words)
Although at first glance the dove prism appears to be a good candidate for dispersion (due to the angular entrance of the light beam), transmission of light through the prism is actually equivalent to passage through a slab of glass with the side benefit of image rotation.
Amici prisms are expensive and difficult to fabricate because the roof angle must be held to a tolerance of 2-4 seconds of arc to avoid producing a double image artifact.
Penta prisms are often referred to as an optical square (as applied to surveying instruments), because the incoming light beam is deviated at the same angle, regardless of the prism orientation with respect to the line of sight.
  More results at FactBites »



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