20 August 2022, Volume 9, Issue 8, pp. 842-964

Light can carry quantum information encoded in its polarization direction or in its spatial distribution of intensity. The image shows a geared microring resonator integrated with a quantum light source in a two-dimensional material (foreground) that enables to couple these two degrees of freedom at the single photon level. The device emits twisted quantum light with orbital angular momentum enabling high-dimensional quantum communication. See Ma et al., pp. 953–958. See print version of the cover."