Collective dipole-dipole interactions in an atomic array
Collective dipole-dipole interactions in an atomic array
复制标题
原子阵列中的集体偶极子相互作用
DOI：
10.1103/physreva.94.013847
复制
发表时间：
2016
影响因子：
2.9
通讯作者：
Francis Robicheaux
中科院分区：
文献类型：
--
作者：
R. T. Sutherland;Francis Robicheaux
研究了原子阵列中原子的相干光子散射。研究发现，由于协同光子交换，平行于激光传播方向（$\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{k}}$）的阵列原子的激发概率沿$\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{k}}$方向随激光的失谐而增长或衰减。由于$a=j\ensuremath{\lambda}/2$原子分离系统的对称性，使得激发分布和散射辐射在阵列中心附近突然变得对称，其中$j$为整数，$\ensuremath{\lambda}$为跃迁波长。对于$al\ensuremath{\lambda}/2$的原子分离，非辐射态（$\mathrm{\ensuremath{\Gamma}}\ensuremath{\sim}0$）的集合破坏了所描述的趋势。为了解释这一惊人的结果，在$N\ensuremath{\rightarrow}\ensuremath{\infty}$极限下进行了带结构计算，得到了本征模对准动量的衰减率和集体兰姆位移。计算结果表明，阵列中光子的集体交换强烈影响其散射辐射，通过正确选择驱动激光的角度，可以很容易地操纵集体兰姆位移并直接激发超辐射或次辐射本征模式。
The coherent photon scattering of atoms in an atomic array is studied. It is found that due to cooperative photon exchanges, the excitation probability of an atom in an array parallel to the direction of laser propagation ($\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{k}}$) will either grow or decay along $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{k}}$, depending on the detuning of the laser. The symmetry of the system for atomic separations of $a=j\ensuremath{\lambda}/2$ causes the excitation distribution and scattered radiation to abruptly become symmetric about the center of the array, where $j$ is an integer and $\ensuremath{\lambda}$ is the transition wavelength. For atomic separations of $al\ensuremath{\lambda}/2$, a collection of nonradiating states ($\mathrm{\ensuremath{\Gamma}}\ensuremath{\sim}0$) disrupts the described trend. In order to interpret this surprising result, a band-structure calculation in the $N\ensuremath{\rightarrow}\ensuremath{\infty}$ limit is conducted, where the decay rates and the collective Lamb shifts of the eigenmodes versus quasimomentum are obtained. This calculation shows that the collective exchange of photons in an array strongly affects its scattered radiation, allowing one to easily manipulate the collective Lamb shift and directly excite either superradiant or subradiant eigenmodes by correctly choosing the angle of the driving laser.