The interference properties of single-photon vortex beams in Mach–Zehnder interferometer

Orbital angular momentum (OAM) is a unique degree of freedom for vortex beams. It is very important to study the interference of vortex beams carrying OAM in quantum information science. In this paper, we study the interference phenomenon of vortex beams based on a stable and adjustable Mach–Zehnder (MZ) interferometer using a laser and a single-photon as light sources. Furthermore, we also show the evolution of the different initial states in the MZ interferometer, and the interferograms of initial states vary with changing the interferometer phase. Our research not only helps us to understand the special phenomenon of OAM in the MZ interferometer but also provides some theoretical and experimental support for OAM as a quantum information carrier.