Polarization by reflection


  • This simple method of obtaining plane polarized light by reflection was discovered by malus in 1808
  • We found that when a beam of light is reflected from the surface of a transparent medium like glass or water, the reflected light is partially polarized and degree of the polarization varies with angle of incidence
  • The percentage of polarized light is greatest in reflected beam when light beam is incident on the transparent medium with an incident angle equal to the angle of polarization
  • For ordinary glass with refractive index =1.52 ,angle of polarization is 57.50
  • Figure below shows the polarization of light by reflection


     
  • we can use a Polaroid as an analyzer to show that reflected light is plane polarized . we rather say that reflected light is partially plane polarized
  • the examination of transmitted light shows the variation in intensity indicating that the light is partially polarized
  • The vibrations of this plane polarized reflected light are found to be perpendicular to the plane of incidence and therefore ,the reflected light is said to be plane polarized in the plane of incidence

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