Polarization by Glass Plates - Physics Demonstrations - Polarization by Glass Plates | Physics Undergraduate Labs

Use only Class 2 or 3R lasers (< 5 mW) for classroom demonstrations. Never direct the beam toward students or allow specular reflections into the audience. Position the reflected beam above or to the side of student viewing areas. Brief the class about not looking directly at the beam or reflections.

Purpose

Students observe that light reflected from a stack of glass plates at Brewster's angle is linearly polarized, while the transmitted beam is partially polarized in the orthogonal direction. A polaroid sheet verifies the polarization state of each beam.

Stack of glass plates mounted at an angle in a black cylindrical holder with adjustment knob, illuminated by a red laser beam with the reflected spot visible on the blackboard behind; two views shown

Figure 1: Glass plate stack mounted in an adjustable holder, illuminated by a red laser. The reflected beam is visible on the blackboard. A polaroid sheet is used to verify polarization of the reflected and transmitted beams.

Glass Plate Set

1

Safety Warnings

Warning: Laser Safety

Purpose