## Polarization Exploration

 EM waves traveling in the z-direction.  The red dot represents a point on the z-axis.  The E-field vectors for this point are displayed at right. Looking down the z-axis toward the light source.  Vectors show the magnitude and direction of E-fields.

Amplitude of E-field X (must be a number between 0 and 8):

Amplitude of E-field Y (must be a number between 0 and 8):

Phase Difference (as a factor of Pi):    *Pi

The above applets show the result of adding two perpendicular electric fields together.  Each field is part of an EM wave traveling along the z-axis.  Each E-field is shown separately on the left had side.  The red dot represents the E-field at a point on the z-axis.  The right-hand side applet shows both E-fields and their sum at the same point represented by the red dot in the left applets. Restart

#### Linear Polarization

Enter the following values.  Ex=8, Ey=0, Phase Difference=0.

You have created a light wave, traveling along the z-axis, with its electric field component in the x direction.  This is an example of a linearly polarized light wave.

a) What is the vector equation of the wave you just created?

b) The wave you just specified was polarized in the x-direction.  What equations for Ex and Ey would result in light that is linearly polarized along a plane 45ş above the +x axis?

c) What equations for Ex and Ey would result in light that is linearly polarized along a plane less than 45ş above the +x axis?

#### Circular and Elliptical Polarization

Light is linearly polarized when its E-field component is in a plane.  Circular and elliptical polarization occurs when two or more linearly polarized waves add together such that the E-field of the net wave rotates.  For circularly polarized light the direction of the E-field rotates but its magnitude stays the same.  For elliptically polarized light both the magnitude and the direction of the E-field varies.  For example, if you enter the following values, Ex=8, Ey=8, and Phase Difference=0.5, a wave that is right circularly polarized will result.

d) What equations for Ex and Ey would result in light that is left circularly polarized?

e) What equations for Ex and Ey would result in light that is right elliptically polarized?

Exploration by Melissa Dancy and Wolfgang Christian