“On Donuts and Peanuts”: Strongly orientation-dependent spontaneous emission rates in any nanophotonic environment

According to quantum electrodynamics, the emission rate of a two-level quantum emitter is described by Fermi´s golden rule. Currently, there are many efforts to control the emission rate of quantum emitters by optimizing the nanoscale environment via the local density of optical states (LDOS) by, e.g., reflecting interfaces, microcavities, photonic crystals, or plasmonic nanoantennae. Control of spontaneous emission is notably relevant to solid-state applications, including miniature lasers and light-emitting diodes, single-photon sources for quantum information, and solar energy harvesting.