Exceptional-point-based accelerometers with enhanced signal-to-noise ratio
Exceptional-point-based accelerometers with enhanced signal-to-noise ratio
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DOI：
10.1038/s41586-022-04904-w
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发表时间：
2022-07-28
期刊：
影响因子：
64.8
通讯作者：
Kottos, Tsampikos
中科院分区：
文献类型：
--
作者：
Kononchuk, Rodion;Cai, Jizhe;Kottos, Tsampikos
异常点（EP）是非厄米简并，其中特征值及其相应的特征向量合并（1-4）。最近，EPs作为一种增强传感器响应性的手段引起了人们的关注，通过在其附近发生突然谐振失谐（5-20）。然而，在许多情况下，EP的实施伴随着噪声增强，导致传感器性能的下降（15-20）。多余的噪声可以是基本性质的（由于特征基崩溃）或与用于实现EPs的放大机制相关的技术性质。在这里，我们表明，使用基于ep的奇偶时间对称（21,22）机电加速度计，增强的技术噪声可以被对应用加速度的增强响应所超越。通过利用传输峰简并（TPD）产生的失谐（当传感器与传输线弱耦合时形成）作为灵敏度的度量来减轻由于特征基坍缩引起的噪声。这些TPDs发生在双正交特征基仍然完整的频率和控制参数下，并且与奇偶时间对称传感器的EPs不同。与远离TPD的配置相比，我们的设备显示出三倍的信噪比提高。
Exceptional points (EP) are non-Hermitian degeneracies where eigenvalues and their corresponding eigenvectors coalesce(1-4). Recently, EPs have attracted attention as a means to enhance the responsivity of sensors, through the abrupt resonant detuning occurring in their proximity(5-20). In many cases, however, the EP implementation is accompanied by noise enhancement, leading to the degradation of the sensor's performance(15-20). The excess noise can be of fundamental nature (owing to the eigenbasis collapse) or of technical nature associated with the amplification mechanisms utilized for the realization of EPs. Here we show, using an EP-based parity-time symmetric(21,22) electromechanical accelerometer, that the enhanced technical noise can be surpassed by the enhanced responsivity to applied accelerations. The noise owing to eigenbasis collapse is mitigated by exploiting the detuning from a transmission peak degeneracy (TPD) - which forms when the sensor is weakly coupled to transmission lines - as a measure of the sensitivity. These TPDs occur at a frequency and control parameters for which the biorthogonal eigenbasis is still complete and are distinct from the EPs of the parity-time symmetric sensor. Our device shows a threefold signal-to-noise-ratio enhancement compared with configurations for which the system operates away from the TPD.