Two Lectures on the Wave‐Particle Duality

Angela Gencarelli

A Korablev Gregory

Renaud Mathevet, Bénoît Chalopin

We present a simple and portable experimental setup that demonstrates the concept of wave–particle duality. Our setup is constructed by modifying the Thorlabs Quantum Optics Educational Kit and can be used in various educational contexts, ranging from general public demonstrations to classroom experiments both in wave optics and quantum mechanics lectures. We propose a set of experiments that provide a pedagogical progression in which basic quantum concepts are introduced systematically.

Bruce R. Wheaton

John Morrison

Todorka L. Dimitrova, Antoine Weis

Single-photon interference is a beautiful manifestation of the wave–particle duality of light and the double-slit Gedankenexperiment is a standard lecture example for introducing quantum mechanical reality. Interference arises only if each photon can follow several (classical) paths from the source to the detector, and if one does not have the possibility to determine which specific path the photon has taken. Attaching a specific label to the photon traveling along a specific path destroys the interference. However, in some cases those labels can be erased from the photon between leaving the apparatus and being detected, by which interference can be restored, a phenomenon called quantum erasing. We present lecture demonstration experiments that illustrate the wave–particle duality of light and the phenomenon of quantum erasing. Both experiments are first shown with strong light and, in a second step, on a photon-by-photon basis. The smooth transition from the quantum to the classical case can be shown in real time by varying the incident light intensity.