  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.
