A double demonstration experiment for the dual nature of light
Todorka L. Dimitrova, Antoine Weis
A new lecture demonstration experiment for illustrating the wave-particle dualism of light is proposed. The equipment is based on the interference of two coherent light beams produced in a Mach-Zehnder interferometer. Light from a green laser pointer is used to perform two simultaneous experiments. The expanded laser beam traverses a Mach-Zehnder interferometer, which allows one to create a superposition of two coherent beams and to adjust the period of their interference fringes in a simple way—a didactic tool to illustrate the wave nature of light. The main feature of the experiment is the use of the same equipment to demonstrate the particle nature of light. For this the entering beam is strongly attenuated and photons at the exit of the interferometer are detected by a photomultiplier (PM) with a narrow slit, connected to a speaker. We propose a realization in which both of these experiments can be demonstrated simultaneously. Special design criteria of the set-up are its low cost, its simplicity, its didactical power and its suitability for large lecture halls.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 2, 2007•3 citations