[论文解读] Coherent noise cancellation in optomechanical system with double optical modes

Jia‐shun Yan, Jun Jing|arXiv (Cornell University)|Sep 10, 2020

Mechanical and Optical Resonators参考文献 62被引用 3

一句话总结

本文提出一种双光模光学机械系统，用于弱力传感中的相干量子噪声抵消（CQNC），通过驱动高频模式并探测低频模式，实现通过与近共振辅助模式耦合的反作用噪声抵消。该方案同时满足Routh-Hurwitz与光学弹簧条件，实现系统稳定，在如膜在中间或扭腔探测器等实际三体系统中，实现超越标准量子极限的灵敏度并增强鲁棒性。

ABSTRACT

The coherent quantum noise cancellation (CQNC) strategy has been performed in the single-mode optomechanical systems to promote an ultra-sensitive metrology protocol to break the standard quantum limit. The key idea of CQNC is that the backaction noises arising from radiation pressure and driving can be offset by coupling the optical mode to a near-resonant ancillary mode. In this work, a continuous weak-force sensing under CQNC is developed in a double-mode optomechanical system consisted of two optical modes with distinct frequencies and a mechanical mode. In particular, under the asymmetrical treatment by driving the higher-frequency optical mode, probing the lower-frequency one, and coupling the probe mode to the ancillary mode, our configuration can be used to resemble the conventional CQNC sensing. It is more important to find that the current CQNC strategy simultaneously stabilizes the double-mode system with respect to both the constrained driving power (the Routh-Hurwitz criterion) and the effective positive mechanical damping (the stable optical-spring condition). Moreover, through exploiting the coupling between the probe mode and the ancillary mode under this nontrivial extension of the CQNC strategy (from the single-mode version to the double-mode one), the rotating-wave term and the counter-rotating term are found to be responsible to the system stability and the noise cancellation, respectively. In realistic situations, our scheme can be practiced in a tripartite optomechanical setup with a membrane in the middle and a twisted-cavity-based weak-torque detector.

研究动机与目标

• 将相干量子噪声抵消（CQNC）从单模扩展至双光模光学机械系统。
• 通过抑制反作用噪声，在连续弱力传感中实现超越标准量子极限（SQL）的灵敏度。
• 在满足Routh-Hurwitz判据（驱动功率限制）与有效正机械阻尼（光学弹簧条件）下，确保系统稳定性。
• 研究旋转波项与反向旋转项在噪声抵消与系统稳定性中的作用。

提出的方法

• 系统由两个频率不同的光学模式与一个机械模式组成，采用非对称驱动：高频模式被驱动，低频模式被探测。
• 将辅助模式与探测模式耦合，通过反作用噪声的相消干涉实现相干噪声抵消。
• 对哈密顿量进行线性化，可简化为等效单模系统，从而实现对响应函数与噪声谱的解析处理。
• 应用Routh-Hurwitz判据以确定最大稳定驱动功率，确保系统稳定性。
• 利用光学弹簧条件验证有效正机械阻尼，确保机械稳定性。
• 分析旋转波项与反向旋转项的作用：旋转波项负责系统稳定性，反向旋转项实现噪声抵消。

实验结果

研究问题

• RQ1 CQNC能否成功从单模系统扩展至双光模光学机械系统，以增强弱力传感性能？
• RQ2 驱动高频模式并探测低频模式如何影响系统稳定性与噪声抑制？
• RQ3 旋转波项与反向旋转项在决定系统稳定性与噪声抵消中的作用是什么？
• RQ4 该双模系统能否同时满足Routh-Hurwitz判据与光学弹簧条件下的稳定性？
• RQ5 探测模式与辅助模式之间的耦合如何实现有效的噪声抵消与灵敏度提升？

主要发现

• 该双模光学机械系统通过与辅助模式耦合，实现反作用噪声的相干抵消，从而达到超越标准量子极限的灵敏度。
• 系统在满足Routh-Hurwitz判据（限制驱动功率）与光学弹簧条件（确保有效正阻尼）下均保持稳定。
• 研究发现，旋转波项负责系统稳定性，而反向旋转项则实现噪声抵消。
• 采用高频模式驱动与低频模式探测的配置导致避免正常模分裂，表明强耦合特性，并在机械频率附近实现灵敏度增强。
• 该方案在传统膜在中间结构与新型基于扭腔的弱力矩探测器中均具有高度实际可行性。