PURPOSE: To demonstrate frustrated total internal reflection using microwaves.
DESCRIPTION: A beam of 12cm microwaves reflects internally on the hypotenuse of a right angle paraffin prism. Bringing the hypotenuse of a second identical paraffin prism within a few cm of the first prism allows the wave to be transmitted stra ight through the two prisms.
Sections of four-inch galvanized steel tubing are used as waveguides to maintain the intensity of the beam. Receiving antennas are located in positions to sense both the internally reflected beam and the frustrated beam simultaneously, displaying the signal levels on two overhead projector microammeters.
REFERENCES: (PIRA unknown.) See Demonstration Reference File for further information on this demonstration.
EQUIPMENT: Microwave source, two identical paraffin right angle prisms, three sections of four-inch galvanized steel drain pipe waveguides, and two receivers with overhead projector meters on overhead projector.
SETUP TIME: 10 min.
Go back to Lecture-Demonstration Home Page.