Spontaneously generated structured light

We suggest a method for spontaneous emission in a four-level atomic system driven by vortex light beams that generates structured light. The atom in consideration has two excited states that are closely spaced and linked to the ground state by two control fields. The excited states have the ability to spontaneously decay into a fourth level, known as a metastable state. We demonstrate that in such configuration the orbital angular momentum (OAM) of the vortex pumping light beams can be transferred from both control fields to the spontaneously emitted photons by analyzing the spontaneously generated output spectrum. Furthermore, we discover that by spontaneous emission, the azimuthal phase dependency may be used to develop different kinds of structured light, the spatial intensity distribution of which can be significantly modified by varying the OAM of the control fields. The concept we propose could indeed have significant implications in fields such as optical communication and optical storage, where structured light plays a crucial role.