This is another very useful demonstration for undergraduate students on the quantum effect of light, and how it differs from the classical description. Fascinatingly enough, it appears that this is a lab at the sophomore level. Maybe sophomores nowadays are more "sophisticated" than when I was in college, but this certainly would require quite a bit more knowledge of QM than I would have had back then at this level.
Abstract: We describe a series of experiments used in a sophomore-level quantum physics course that are designed to provide students with a hands-on introduction to quantum mechanics. By measuring correlations, we demonstrate that a helium-neon laser produces results consistent with a classical model of light. We then demonstrate that a light source derived from a spontaneous parametric down-conversion process produces results that can only be described using a quantum theory of light, thus providing a (nearly) single-photon source. These single photons are then sent into a Mach–Zehnder interferometer, and interference fringes are observed whenever the path of the photons cannot be determined. These experiments are investigated theoretically using straightforward quantum-mechanical calculations.
B.J. Pearson and D.P. Jackson, Am. J. Phys. v.78, p.471 (2010).
What makes this paper so wonderful is that it is full of various references and resources, and also discussed many of the physics background information. So for someone who wants to learn about the physics of the phenomena, this is almost a one-stop shop.
This paper compliments the ones that I've mentioned earlier that were also undergraduate laboratory or demonstration.