Spontaneous emission mediated by graphene/hexagonal boron nitride/graphene sandwich structure

Controlling the spontaneous emission of atoms or molecules is an interesting research topic in the field of quantum optics. Here we provide a perspective on modulating the interaction between two quantum emitters through a sandwich structure composed of graphene and hexagonal boron nitride (hBN). The dependence of interaction between quantum emitters on the thickness of hBN and chemical potential of graphene is investigated in detail. When the transition frequency of quantum emitter is located in the hyperbolic band of type I supported by hBN, the radiative state can be easily modulated by adjusting the chemical potential of graphene. So it is flexible to switch the interaction of quantum emitters from superradiant state to subradiant state by external electric field. When the transition frequency of quantum emitter is located in hyperbolic band of type II, the system can be always in the superradiant state. We predict the further research perspectives of spontaneous emission and superradiance with the help of metasurfaces based on two-dimensional materials.

Low-frequency fluorescence spectrum of a laser driven polar quantum emitter damped by squeezed vacuum with finite bandwidth

A two-level quantum emitter with broken inversion symmetry driven by external semiclassical monochromatic high-frequency electromagnetic (e.g., laser) field and damped by squeezed vacuum reservoir with finite bandwidth is presented. The squeezed vacuum source is assumed to be either degenerate parametric oscillator (DPO) or a non-degenerate parametric oscillator (NDPO). It is shown that the shape of low-frequency fluorescence spectrum of the emitter can be effectively alternated by controlling the degree of the squeezed vacuum source degeneration and phase of the squeezing.