High-dimensional encoding schemes have emerged as a novel way to perform quantum information tasks. For high dimensionality, temporal and transverse spatial modes of photons are the two paradigmatic degrees of freedom commonly used in such experiments. Nevertheless, general devices for multi-outcome measurements are still needed to take full advantage of the high-dimensional nature of encoding schemes. We propose a general full-field mode sorting scheme consisting only of up to two optimized phase elements based on evolutionary algorithms that allows for joint sorting of azimuthal and radial modes in a wide range of bases. We further study the performance of our scheme through simulations in the context of high-dimensional quantum cryptography, where high-fidelity measurement schemes are crucial.
@article{arxiv.1905.01175,
title = {Full-field mode sorter using two optimized phase transformations for high-dimensional quantum cryptography},
author = {Robert Fickler and Frédéric Bouchard and Enno Giese and Vincenzo Grillo and Gerd Leuchs and Ebrahim Karimi},
journal= {arXiv preprint arXiv:1905.01175},
year = {2020}
}