量子干涉效应对原子共振荧光和能级布居影响的研究

Spontaneous emission of atoms is a main source of quantum noise of various optoelectronic devices and one of physical difficulties in realizing the high-frequency laser. It has been paid much attention how to inhibit spontaneous emission. Recent research has shown that spontaneous emission can be effectively depressed by cancellation quantum interference between different spontaneous decay pathways of atoms. As a result, the level population, the spectrum and the photon statistics of resonance fluorescence can be greatly changed. In this project, we investigated theinfluence of quantum interference on spectrum of the resonance fluorescence emitted from a four-level atom of V configuration which is driven by two coherent fields, and found that the spectral line width of the observing fluorescent light exclusively contributed by one transition can be controlled by quantum interference in other transitions. According to this result, we have suggested an approach to creat ultral-narrow width spectral lines of resonance fluorescence by use of quantum correlations between transitions in different frequencies. We also investigated spontaneous emission of a three-level atom consisting of two upper levels and one lower level in a multilayer dielectric medium and studied an approach for creating quantum correlation between dipole-forbiden-transition levels by use of the vacuum anisotropy induced by an inhomogeneous medium. We showed that a strong quantum interference similar to that for an atom with two nearly parallel or antiparallel dipole moments in free space arises due to the influence of anisotropic vacuum when the atom is placed in a three-layer dielectric plate cavity and wave guide, and one -dimensional photonic crystal. At the same time, we studied the influence of quantum interference on the squeezing spectrum of the resonance fluorescence emitted from a V-type three-level atom and a -type four-level atom which are driven by coherent fields. We showed that quantum interference can greatly enhance squeezing in the components of phase quadratures at atomic frequency and change the squeezing spectrum .

本项目研究原子跃迁的不同路径间的量子干涉的形成和调节方法，以及量子干涉效应对原子共振荧光和能态布居几率的影响，阐明如何利用这一效应控制原子共振荧光和能级布居几率。本项目的完成，将为实现短波长激光、原子尺度光量子开关以及纯量子态的制备和保持提供新的科学原理和途径，并为相关的实验提供理论基础。