CIRCULAR AND ELLIPTICAL POLARIZER

CIRCULAR AND ELLIPTICAL POLARIZER

1. WEL-COME TO RAI SAHEB BHANWAR SINGH COLLEGE NASRULLAGANJ

2. PHYSICS PRESENTATION Topic - Circular and Elliptical Polarizer Presented to Presented by Gyan rao D hote Sanjay Panwar

3. Circular polarizers - Circular polarizers , also referred to as  circular polarizing filters , can be used to create  circularly polarized  light or alternatively to selectively absorb or pass clockwise and counter-clockwise circularly  polarized  light. They are used as polarizing filters in photography  to reduce oblique reflections from non-metallic surfaces, and are the lenses of the  3D glasses  worn for the viewing some  stereoscopic  movies (notably, the  RealD 3D  variety), where the polarization of light is used to differentiate which image should be seen by the left and right eye

4. There are several ways to create circularly polarized light, the cheapest and most common involves placing a  quarter-wave plate  after a  linear polarizer  and directing  unpolarized light  through the linear polarizer. The linearly polarized light leaving the linear polarizer is transformed into circularly polarized light by the quarter wave plate. The transmission axis of the linear polarizer needs to be half way (45°) between the fast and slow axes of the quarter-wave plate . In the arrangement above, the transmission axis of the linear polarizer is at a positive 45° angle relative to the right horizontal and is represented with an orange line. The quarter-wave plate has a horizontal slow axis and a vertical fast axis and they are also represented using orange lines. In this instance the unpolarized light entering the linear polarizer is displayed as a single wave whose  amplitude  and angle of linear polarization are suddenly changing. I

5. circularly polarized when viewed from the receiver . Because the quarter-wave plate is made of a  birefringent  material, when in the wave plate, the light travels at different speeds depending on the direction of its electric field. This means that the horizontal component which is along the slow axis of the wave plate will travel at a slower speed than the component that is directed along the vertical fast axis. Initially the two components are in phase, but as the two components travel through the wave plate the horizontal component of the light drifts farther behind that of the vertical. By adjusting the thickness of the wave plate one can control how much the horizontal.

6. ELLIPTICAL POLARIZATION-In   electrodynamics ,  elliptical polarization  is the  polarization  of  electromagnetic radiation  such that the tip of the  electric field   vector  describes an  ellipse  in any fixed plane intersecting, and  normal  to, the direction of propagation. An elliptically polarized wave may be resolved into two  linearly polarized waves  in  phase quadrature , with their polarization planes at right angles to each other. Since the electric field can rotate clockwise or counterclockwise as it propagates, elliptically polarized waves exhibit  chirality . Other forms of polarization, such as  circular  and  linear polarization , can be considered to be special cases of elliptical polarization.

7. Mathematical description of elliptical polarization- The  classical   sinusoidal  plane wave solution of the  electromagnetic wave equation  for the  electric and   magnetic  fields is ( cgs units )

8. END