The Spatial And Spectral Properties Of Collective Radiation Are Regulated By Super- And Subradiance

Spontaneous emission results from the interaction of atoms with an electromagnetic vacuum field.Since atoms are affected by the electromagnetic environment,quantum interference can be established to effectively regulate the spontaneous emission of atoms.In a multiatomic system,the atoms interact with each other to produce a series of interesting quantum optical effects.The quantum correlation will lead to the collective behavior of the radiation system,which can signifiicantly change the radiation properties,especially can produce collective superradiation,subradiation,and more abundant space-oriented radiation effects.In this paper,a series of spatially directed radiation effects generated by selective excitation of a quantum antenna composed of three atoms by a weak laser field and their modulation schemes are studied.We first study the spatial and spectral properties of the collective radiation intensity of the three-atom antenna under different spatial geometrical configurations,including one-dimensional linear atomic chain,isosceles triangle,and arbitrary triangle configurations.Among them,only one atom is driven by an external laser field,so that its stimulated radiation properties are regulated by the superradiative and subradiative dynamics established by the other diatomic systems.For a one-dimensional linear atomic chain,we analyze in detail the distribution of its radiation intensity in two spatial modes perpendicular to and along the axis of the atom,and based on this,we give the geometric conditions for realizing the spatial one-way scattering of the three-atom quantum antenna.For the triangular configuration,the spatial angular distribution of radiation intensity at different atomic spacing is investigated,and the physical mechanism of radiation intensity constructive and destructive interference is analyzed.In addition,the resonance fluorescence spectra of the driven atoms coupled with the light and dark states of the diatoms are calculated,and the collective spectrum characteristics are analyzed by determining the energy spectrum distribution of the three-atom antenna.We also study the spatial properties of the two-photon correlation generated by the three-atom antenna in various spatial geometrical configurations and their quantum regulation schemes.For one dimensional linear atomic chain,when coupled with laser field selective drive chain end chain of atoms and the center of an atomic chain.By comparing the radiation intensity and the intensity-intensity correlation function,we find that the collective radiation of the three-atom antenna can show different photon statistical characteristics in different directions,and found that the space-directed superbeam effect can be controlled by properly adjusting the distance between the atoms and the frequency of the driving laser,so that the three-atom chain can become a highly oriented two-photon nanoantenna.By analyzing the spatial patterns of the radiation intensity and the intensity-intensity correlation function,it is found that these highly directed superbunching effects are caused by the phase difference between the displaced atom and the diatomic system,which leads to the destructive interference of the radiation,and thus significantly inhibits the single photon emission process.Based on the analysis of the one-dimensional atomic chain pattern,we also investigate the two-photon correlation properties of the triangular configuration.Finally,we summarize the work of this paper and look forward to the follow-up work.