Young's Double-Slit Interference Demonstration with Single Photons

The interference of single photons going through a double slit is a compelling demonstration of the wave and particle nature of light in the same experiment. Single photons produced by spontaneous parametric down-conversion can be used for this purpose. However, it is particularly challenging to implement this due to coherency and resolution challenges. In this article, we present a table-top laboratory arrangement suitable for the undergraduate instruction laboratory that overcomes these challenges. The apparatus scans a single detector to produce a plot showing the interference patterns of single photons. We include experimental data obtained using this setup, demonstrating double-slit and single-slit interference as well as quantum erasing through the use of sheet polarizers. (C) 2024 Published under an exclusive license by American Association of Physics Teachers.