AI 中文总结
该研究提出仅用最低两阶厄米-高斯模式的空间模式解复用（SPADE）测量，在分辨非相干点源时抗噪声性能优于直接成像（DI），每像素背景信号光子比0.11时仍接近量子极限，为天文观测等场景提供实用探测方案。
AI 中文摘要
我们从理论上预测并实验演示：仅使用最低两阶厄米-高斯模式的简化空间模式解复用（SPADE）测量，在分辨单源与两个非相干点源时，对背景噪声具有显著鲁棒性。我们建立了包含均匀背景噪声的理论框架，推导了解析的切尔诺夫指数表达式，结果显示在所有源间距下，SPADE均优于直接成像（DI）。实验结果证实，即使每像素背景信号光子比为0.11，基于SPADE的假设检验也能接近量子极限。这一优势源于SPADE能将源信息集中到最少的探测模式中，降低了累积背景噪声的影响。我们的发现为背景噪声不可避免的应用场景（如天文观测和量子传感）提供了实用的探测方案。
英文摘要
We theoretically predict and experimentally demonstrate that a reduced spatial-mode demultiplexing (SPADE) measurement using only the two lowest-order Hermite-Gaussian modes exhibits remarkable robustness against background noise in discriminating between a single source and two incoherent point sources. We establish a theoretical framework incorporating uniform background noise and derive an analytical Chernoff exponent expression, showing that SPADE consistently outperforms direct imaging (DI) across all source separations. Experimental results confirm that SPADE-based hypothesis testing approaches the quantum limit even when the background-to-signal photon ratio per pixel is 0.11. This advantage stems from SPADE's ability to concentrate source information into minimal detection modes, reducing the cumulative background noise impact. Our findings provide a practical detection scheme for applications where background noise is inevitable, such as astronomical observations and quantum sensing.
