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Unformatted text preview: Polarization by reflection Reflection and Refraction 4.3 Reflection and Polarization Polarization by scattering • Unpolarized light can be polarized by reflection at an angle from a dielectric surface. • The reflected light is completely polarized at a special angle “Brewsters angle” • If the incident light is polarized with the E field in the plane of incidence, then at Brewsters angle no light is reflected. All the light is transm itted. Reflection and refraction The Incident light is polarized in the plane of incidence. (plane of the picture) W hen the sum of o q2 + qp =90 .the intensity of the refl ected light is zero. At this angle the E field of the light in the glass is parall el to the direction of the refl ected wave, therefore cannot propagate in that direction. => No Refl ection Total Transm ission. Brewster’s angle Polarizing angle
qP n 1 qP n 2 qp q2 Snell’s law n1 sin qp = n 2 sin q2 sin q2 = cos qp => tan qp = n 2 n1 Question Suppose you wanted to have a polarized light beam to be completely transmitted at at the air water interface. W hat conditions would you use? Question Suppose you wanted to have a polarized light beam to be completely transmitted at at the air water interface. W hat conditions would you use?
qp n1 =1.00 Light with E field in the plane of incidenc e Angle of incidence equal to the pol ari zing angl e n =1.333 2 ta n qp = n 2 = 1.3 33 n 1 qp = 53 o 1 Unpolarized light incident at the polarizing angle is polarized on reflection
qP n 1 qP pol ari zation ^ to the plane of incidence. qp q2 Polarization by reflection n 2 no filter pol ari zing filter 2 ...
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