arXiv 2005.122132020-05physics.opticsphysics.ins-det

超越Petermann极限：特殊点能提高传感器精度吗？

Beyond the Petermann limit: can exceptional points increase sensor precision?

David D. Smith, Hongrok Chang, Eugeniy Mikhailov, Selim M. Shahriar

摘要：

在最大耗散非厄米特系统中锁定区附近的实验，例如，传统的激光陀螺仪在死区附近遇到了Petermann极限，在Petermann极限处，过量的噪声精确地抵消了任何比例因子的增强，导致精度没有总体增强。因此，人们可能会得出这样的结论，即例外点（EP）通常不能用于提高激光传感器的精度。事实上，使用线性本征模分析，我们表明，Petermann极限不仅适用于最大耗散系统，但对于任何类型的EP，由于事实上，EP是旋转不变的。然而，事实证明，这种限制来自线性假设。我们发现，非线性打破了旋转对称性，使不同类型的EP不再是等同的阈值以上。特别是，对于足够高的测量频率，EP在保守耦合系统具有饱和不平衡可能会导致基本精度的增加超过彼得曼限制。重要的是，我们发现，只有一个模式激光在这些条件下。我们表明，拍音可以恢复与辅助模式的干扰，但这对依赖于恢复方案的量子和经典噪声的后果。因此，还有待观察是否可以设计出实际的实验，可以利用这种增强。

英文摘要：

Experiments near the lock-in region in maximally dissipative non-Hermitian systems, e.g., conventional laser gyroscopes near the deadband, have run up against the Petermann limit, where excess noise exactly cancels any scale-factor enhancement resulting in no overall enhancement in precision. As a result, one might be tempted to conclude that exceptional points (EPs) generally cannot be used to increase the precision of laser sensors. Indeed, using a linear eigenmode analysis we show that the Petermann limit applies not just to maximally dissipative systems, but for any type of EP, owing to the fact that EPs are rotationally invariant. It turns out, however, that this restriction comes from the assumption of linearity. We find that nonlinearity breaks the rotation symmetry such that the different types of EPs are no longer equivalent above threshold. In particular, for sufficiently high measurement frequencies, EPs in conservatively coupled systems having a saturation imbalance can lead to an increase in the fundamental precision beyond the Petermann limit. Importantly, we find that only one mode lases under these conditions. We show that the beat note can be recovered by interference with an auxiliary mode, but that this has consequences for the quantum and classical noise that depend on the recovery scheme. Thus, it remains to be seen whether practical experiments can be designed that can take advantage of this enhancement.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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