Azimuthally dependent spontaneous emission from a coherently microwave-field driven four-level atom-light coupling scheme

Abstract

We present a novel technique that makes use of vortex light beams for generating spatially structured spontaneously emission in a atomic four-level configuration. This atomic configuration consists of two closely spaced excited levels linked to a microwave field and two optical vortex fields connecting them to the ground state. After that, the excited states eventually decays to a fourth metastable level. We find that spatially dependent spontaneous emission spectra may be obtained by efficiently transferring the orbital angular momentum (OAM) of the vortex-pumping light beams to the spontaneously emitted photons. This enables the targeted quenching of spontaneous emission in specific azimuthal regions, while simultaneously enhancing it in others. By effectively controlling the OAM of optical vortices and taking into account the correlations of the atomic gas and their collective decay to a metastable state via superradiance, it might be feasible to experimentally modify the probabilistic emission process with deterministic radiation. The approach we propose might be helpful in controlling the quantum level emission characteristics via the nonlinear interaction of the atom–vortex-beam light.