Beating the standard quantum limit:: phase super-sensitivity of N-photon interferometers
Beating the standard quantum limit:: phase super-sensitivity of N-photon interferometers
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DOI：
10.1088/1367-2630/10/7/073033
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发表时间：
2008-07-18
影响因子：
3.3
通讯作者：
Takeuchi, Shigeki
中科院分区：
文献类型：
--
作者：
Okamoto, Ryo;Hofmann, Holger F.;Takeuchi, Shigeki
量子计量学为光学相位测量提供了比传统方法更高的灵敏度。在这里，我们提出了一般情况下的相位灵敏度理论，其中检测概率由 N 光子干涉条纹给出。我们发现相位灵敏度对检测的固有效率 eta 和干涉条纹可见度 V 有复杂的依赖性。最重要的是，提供最大相位灵敏度的相位通常与干涉条纹斜率最大的相位不同，正如之前所假设的那样。我们确定了可以实现量子增强灵敏度的参数范围。为了说明这些理论结果，我们进行了 eta = 3/4 和 V = 82 +/- 6% 的四光子实验（我们之前工作的扩展（Nagata 等人 2007 Science 316 726）），并发现在与给出干涉条纹最大斜率的相位不同的相位处，相位灵敏度比标准量子极限大 1.3 倍。
Quantum metrology promises greater sensitivity for optical phase measurements than could ever be achieved classically. Here, we present a theory of the phase sensitivity for the general case where the detection probability is given by an N photon interference fringe. We find that the phase sensitivity has a complicated dependence on both the intrinsic efficiency of detection eta and the interference fringe visibility V. Most importantly, the phase that gives maximum phase sensitivity is in general not the same as the phase at which the slope of the interference fringe is a maximum, as has previously been assumed. We determine the parameter range where quantum enhanced sensitivity can be achieved. In order to illustrate these theoretical results, we perform a four-photon experiment with eta = 3/4 and V = 82 +/- 6% (an extension of our previous work (Nagata et al 2007 Science 316 726)) and find a phase sensitivity 1.3 times greater than the standard quantum limit at a phase different to that which gives maximum slope of the interference fringe.