Noise-robust discrimination of incoherent point sources with spatial-mode demultiplexing
Abstract
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.
Versions
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BibTeX
@misc{liu2026noiserobust,
title = {{Noise-robust discrimination of incoherent point sources with spatial-mode demultiplexing}},
author = {Jian-Qiang Liu and Chao-Ning Hu and Jun Xin and Xiao-Ming Lu},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2608.01765},
eprint = {2608.01765},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.01765},
}
RIS
TY - UNPB
TI - Noise-robust discrimination of incoherent point sources with spatial-mode demultiplexing
AU - Jian-Qiang Liu
AU - Chao-Ning Hu
AU - Jun Xin
AU - Xiao-Ming Lu
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2608.01765
UR - https://arxiv.org/abs/2608.01765
AB - 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.
ER -