基于多光子高阶OAM纠缠实现相位及转动的超灵敏测量

Phase supersensitivity measurement plays a fundamental role in a number of applications such as gravitational wave detection, where of key is how to break the standard quantum limit. Different from traditional methods, this project combines the traditional multiphoton path entanglement, NOON state, with high-order orbital angular momentum (OAM) state, to perform high-efficiency coupling between multiphoton path information and high-order OAM states, and therefore, realizing the preparation and manipulation of multiphoton high-order OAM entangled states with N=4 and OAM=500. As our method allows the simultaneous measurement of both path superposition and OAM superposition, we can reach a measurement precision two times better than the traditional NOON state only considering path entanglement. Therefore we are able to beat the standard quantum limit. Particularly, if the tiny phase change is induced by a rotating object, we find that our method can be further utilized to realize supersensitivity remote sensing of rotational angle and velocity, with a precision three orders better than traditional methods, namely, N*OAM. Our work may find potential applications not only in the field of fundamental physics such as quantum mechanically multiphoton interference, but also in the field of engineering physics such as quantum precision measurement and sensing technique.

相位的精密测量在诸多领域，如引力波探测等具有极重要的应用，而如何突破标准量子极限是核心问题。与传统方法不同，本项目的研究亮点是在传统的多光子路径纠缠NOON态的基础上，通过额外引入新型的轨道角动量(OAM)自由度，操控多光子的路径信息与高阶OAM态的高效耦合，从而实现多光子高阶OAM纠缠态(N=4, OAM=500)的制备与调控。由于我们的方案允许同时对路径叠加态和OAM叠加态的双重测量，因此我们获得相位的测量精度将会比只考虑路径纠缠的NOON态提升一倍，从而更加显著的突破标准量子极限。特别地，当微小的相移由物体的转动引起时，我们的方案还可用于实现转角或转速的超灵敏度测量，测量的精度理论上将比传统的方法提高约3个数量级(正比于N*OAM)。我们的研究不仅在基础物理方面对于探讨量子力学多光子干涉的基本原理，而且在工程物理方面对于量子精密测量及传感技术都具有重要的应用价值！

该项目主要研究目标是围绕光子高维轨道角动量及其叠加态的制备，并结合量子纠缠调控，研究对转动及相位的高灵敏度测量。主要成果的研究水平及创新性主要体现在以下五个方面：1、超净室装修与实验平台升级，搭建了多光子纠缠态（含四光子）实验平台建设及基本性能测试。2、实验验证了线性Doppler效应和转动Doppler效应等效性。3、实现了光子水平下光学涡旋态的高灵敏探测技术。4、实验实现了120mm自由空间转动Doppler效应和转动的高灵敏测量，并实现了基于OAM纠缠的非定域的旋转Doppler效应。5、提出基于双光子波函数调控的高灵敏单光子人脸识别技术。