This dataset contains both the raw data and final results of a detailed study of orbital angular momentum (OAM) transfer in a four-wave mixing (FWM) process in rubidium vapour.
The full Laguerre-Gauss mode decomposition of the pump beams and generated 420 nm field were found via Fourier analysis of the interferogram formed at the output of a Dove prism interferometer. Both the raw images and final results are included in the dataset. In addition, we include the predicted mode decomposition of the 420 nm field and the unobserved 5230 nm field, which is also generated in the FWM process.
These results show that the OAM-distribution between the two generated fields depends on the amount of OAM carried by the pump beams. For small values of pump OAM nearly all of the OAM is transferred to the 420 nm light. For larger values of pump OAM the 420 nm OAM-spectrum broadens, indicating that the 420 nm and 5230 nm photon pairs are generated in an OAM-entangled state. Using the measured 420 nm mode decomposition, we infer the spiral bandwidth, related to the width of the OAM-spectrum, and the entanglement entropy of this state.