【摘要】 利用原子约化密度算符主方程的方法研究了多模压缩真空态光场中二能级原子的双光子荧光谱。我们发现存在一种Rabi振荡阈值,在阈值之下原子的简并双光子荧光谱呈现洛仑兹线型单峰结构。在阈值之上具有三峰结构。其三峰的线宽和峰高均呈现很强的相敏性,中峰线宽可小于热光场中的线宽,但大于真空场中双光子的自然线宽,两边峰的线宽随压缩光的强度增大而增宽,边峰到中峰的距离也依赖于压缩真空态光场的压缩特征。更多还原

【Abstract】 The two -photon fluorescence specturm of a two- level atom bathed in a multimode squeezed vacuum is studied by means of master equation method of the atom density operator. It is found that these exists a Rabi oscillation thseshold for the degenesate two -photon process.The two -photon fluorescence spectrum of the atom exhibits a single peak structure of Lonenzian profile below the threshold and changes into a three -peak structure above it. Both the width and height of the three peaks depend strongly on the squeezing phase of the squeezed vacuum. The width of the central peak can be narrower than that of thermal light field but is larger than that of natural two -photon line -width in vacuum. The widths of the two side - peaks increase with the level of squeezing of the squeezed light field and the frequency spacing between the central and side peaks also varies with the squeezing param-eties.更多还原