We have developed and evaluated a quantum interactive learning tutorial (QuILT) on a Mach–Zehnder
interferometer with single photons to expose upper-level students in quantum mechanics courses to
contemporary quantum optics applications. The QuILT strives to help students develop the ability to
apply fundamental quantum principles to physical situations in quantum optics and explore the
differences between classical and quantum ideas. The QuILT adapts visualization tools to help
students build physical intuition about counter-intuitive quantum optics phenomena with single
photons including a quantum eraser setup and focuses on helping them integrate qualitative and
quantitative understanding. We discuss findings from in-class evaluations.