Adaptive optics for single photons in orbital angular momentum modes with parametrically varied emulated turbulence

Orbital angular momentum modes are a common choice for higher-dimensional encoding of photonic qubits. When transported across large distances, these qubits (or qudits) will pass through atmospheric turbulence and suffer aberrations leading to qubit errors, information loss, entanglement degradation, and loss of quantum behavior. In order to quantify some of these effects, we have developed an atmospheric turbulence emulator which allows us to finely control parameters that determine turbulence strength. In this paper, we describe our turbulence emulator and our methods of coupling orbital angular momentum qubits into the system. We present a quantitative demonstration of the degradation of classical orbital angular momentum modes in turbulence. Finally, we discuss ongoing efforts to measure the loss of quantum behavior in orbital angular momentum qubits due to atmospheric turbulence and the use of adaptive optics to mitigate some of the negative effects of atmospheric turbulence.