Possibility for inhibited spontaneous emission in electromagnetically open parity-time-symmetric guiding structures

Remote sensing and manipulation of quantum emitters are functionalities of significant practical importance in quantum optics. Unfortunately, these abilities are considered as fundamentally challenging in systems of inhibited spontaneous emission. The reason is intimately related to the common perception that, in order to nullify the spontaneous emission decay rate, the system has to be electromagnetically closed, meaning that all loss channels should be avoided, including radiation. However, since radiation is prohibited in these systems, far-field sensing and by reciprocity, also far-field manipulation are considered impossible. Here, we suggest a possible solution to this challenge and theoretically propose an electromagnetically open system that may exhibit a complete inhibition of spontaneous emission while supporting guiding waves. This peculiar functionality is achieved through a feedback wave mechanism that is found in parity-time-symmetric structure. The analysis is based on an exact Green's function derivation as well as full wave simulations involving a realistic design for the sake of future experimental validation.