Optimization of photon storage fidelity in ordered atomic arrays
Optimization of photon storage fidelity in ordered atomic arrays
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DOI：
10.1088/1367-2630/aadb74
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发表时间：
2017-10
影响因子：
3.3
通讯作者：
M. Manzoni;M. Moreno-Cardoner;A. Asenjo-Garcia;J. V. Porto;A. Gorshkov;D. Chang
中科院分区：
文献类型：
--
作者：
M. Manzoni;M. Moreno-Cardoner;A. Asenjo-Garcia;J. V. Porto;A. Gorshkov;D. Chang
原子系综的一个主要应用包括光的量子存储器，其中光学状态可以根据需要可逆地转换为集体原子激发。存在一个众所周知的基本边界上的存储错误，当系综是由麦克斯韦-布洛赫方程的连续介质描述。然而，这些方程是半唯象的，因为它们将原子向感兴趣的模式之外的其他方向的发射视为独立的。另一方面，在诸如密集、有序的原子阵列的系统中，原子彼此强烈地相互作用，并且可以利用发射光的空间干涉来抑制向不想要的方向的发射，从而实现改进的误差界限。在这里，我们开发了一个一般的形式主义，充分考虑空间干涉，并发现最大的存储效率为一个已知的空间输入模式的单个光子到一个离散的，已知位置的原子的集合。作为一个例子，我们应用这种技术来研究一个有限的二维正方形原子阵列。我们表明，这样的系统能够实现与原子数Na成比例的存储误差，如[Na（log Na）2 /Na 2]，并且值得注意的是，原则上仅4 × 4原子的阵列允许小于1%的误差，这与光学深度约为600的无序系综相当。
A major application for atomic ensembles consists of a quantum memory for light, in which an optical state can be reversibly converted to a collective atomic excitation on demand. There exists a well-known fundamental bound on the storage error, when the ensemble is describable by a continuous medium governed by the Maxwell–Bloch equations. However, these equations are semi-phenomenological, as they treat emission of the atoms into other directions other than the mode of interest as being independent. On the other hand, in systems such as dense, ordered atomic arrays, atoms interact with each other strongly and spatial interference of the emitted light might be exploited to suppress emission into unwanted directions, thereby enabling improved error bounds. Here, we develop a general formalism that fully accounts for spatial interference, and which finds the maximum storage efficiency for a single photon with known spatial input mode into a collection of atoms with discrete, known positions. As an example, we apply this technique to study a finite two-dimensional square array of atoms. We show that such a system enables a storage error that scales with atom number Na like ∼ ( log N a ) 2 / N a 2 , and that, remarkably, an array of just 4 × 4 atoms in principle allows for an error of less than 1%, which is comparable to a disordered ensemble with an optical depth of around 600.