PURPOSE: To demonstrate polarization effects in reflections from dielectric and conducting surfaces.

DESCRIPTION: The gizmo in the picture contains a collimated light source and a reflecting dielectric surface at approximately the Brewster angle, which can be rotated as a unit about a vertical axis, and a second reflecting dielectric surface. The light emerges to strike a screen, as shown in the sequence of photographs below. The light reflected off the lower reflector is polarized in the plane of the reflector, which can be verified by rotating the light/reflector unit so that the two reflecting surfaces bend the beam in orthogonal planes or by inserting a polarizing sheet between the two reflectors.

Conducting (metallic) surfaces can be substituted for the dielectric surfaces, showing that there is no polarization in reflection from conducting surfaces.

The sequence of photographs below show the following physical situations:

• two dielectric surfaces with parallel surfaces.
• two dielectric surfaces with perpendicular surfaces.
• two conducting surfaces with parallel surfaces.
• two conducting surfaces with perpendicular surfaces.
• lower conducting surface parallel to upper dielectric surface.
• lower conducting surface perpendicular to upper dielectric surface.

SUGGESTIONS:

REFERENCES: (PIRA 6H20.20)

EQUIPMENT: Mounted polarization by reflection setup with screen and polarizing sheet.

SETUP TIME: None.