Using frustrated internal reflection as an analog to quantum tunneling

Also in teaching quantum physics one would like to bring experiments to the secondary school classroom, if not for “proofing” theories, then at least for illustrating and visualizing concepts. When EM waves are totally internally reflected from the inside of a prism, so called evanescent waves can tunnel through a narrow slit to another prism [1] and the intensity shows the exponential dependence on the width of the slit typical for tunneling. This is an example for quantum tunneling as quantum particles can tunnel as well due to their wave properties. This paper describes our progress from an ineffective microwave tunneling demonstration which we tried out with 5 teachers and 112 students, to a well-known optical demonstration but newly mounted in a small for loan suitcase with an educational script based on our try-outs and the PhET tunneling applet to link quantum concepts to tunneling phenomena.