A Fresnel rhomb is a prism-like device designed in 1817 by Augustin-Jean Fresnel for producing circularly polarized light. In Optics, a prism is a transparent optical element with flat polished surfaces that refract Light. Year 1817 ( MDCCCXVII) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common Polarization ( ''Brit'' polarisation) is a property of Waves that describes the orientation of their oscillations Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 However, in contrast to a wave plate, the rhomb does not utilise birefringent properties of the material. A wave plate or retarder is an optical device that alters the Polarization state of a Light wave travelling through it

The rhomb (usually a right-parallelepiped) is shaped such that light entering one of the small faces is internally reflected twice: once from each of the two sloped faces before exiting through the other small face. In Geometry, a rhombus (from Ancient Greek ῥόμβος - rrhombos “rhombus spinning top” (plural rhombi or rhombuses Properties Any of the three pairs of parallel faces can be viewed as the base planes of the prism The angle of internal reflection is the same in each case, and each reflection produces a 45° (π/4 radians) phase delay between the two linearly polarized components of the light. The radian is a unit of plane Angle, equal to 180/ π degrees, or about 57 The phase of an oscillation or wave is the fraction of a complete cycle corresponding to an offset in the displacement from a specified reference point at time t = 0 Hence on the first reflection, a linearly polarized beam will be elliptically polarized, and will emerge as circularly polarized on the second reflection.

For visible light and a glass rhomb (refractive index n ≈ 1. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 5), an internal reflection angle of incidence of 48° or 54. 6° is required.

See also

• Fresnel equations

External link and references

• Hecht, E. (1987). Optics: Second Edition. Massachusetts: Addison-Wesley Publishing Company, Inc. ISBN 0-201-11611-1
• http://physics.kenyon.edu/EarlyApparatus/Polarized_Light/Fresnels_Rhomb/Fresnels_Rhomb.html