Institut National de la Recherche Scientifique - Énergie Matériaux Télécommunications (INRS-EMT), Montréal, QC, Canada.
Nat Commun. 2021 Apr 23;12(1):2402. doi: 10.1038/s41467-021-22716-w.
The ability to detect ultrafast waveforms arising from randomly occurring events is essential to such diverse fields as bioimaging, spectroscopy, radio-astronomy, sensing and telecommunications. However, noise remains a significant challenge to recover the information carried by such waveforms, which are often too weak for detection. The key issue is that most of the undesired noise is contained within the broad frequency band of the ultrafast waveform, such that it cannot be alleviated through conventional methods. In spite of intensive research efforts, no technique can retrieve the complete description of a noise-dominated ultrafast waveform of unknown parameters. Here, we propose a signal denoising concept involving passive enhancement of the coherent content of the signal frequency spectrum, which enables the full recovery of arbitrary ultrafast waveforms buried under noise, in a real-time and single-shot fashion. We experimentally demonstrate the retrieval of picosecond-resolution waveforms that are over an order of magnitude weaker than the in-band noise. By granting access to previously undetectable information, this concept shows promise for advancing various fields dealing with weak or noise-dominated broadband waveforms.
检测随机事件产生的超快速波形的能力对于生物成像、光谱学、射电天文学、传感和电信等多种领域至关重要。然而，噪声仍然是恢复此类波形所携带信息的重大挑战，因为这些波形通常太弱而无法检测。关键问题是，大多数不需要的噪声都包含在超快速波形的宽频带内，因此无法通过传统方法减轻。尽管进行了大量研究，但没有一种技术可以恢复未知参数的噪声主导的超快速波形的完整描述。在这里，我们提出了一种涉及信号频谱相干内容的被动增强的信号去噪概念，该概念能够以实时和单次拍摄的方式完全恢复隐藏在噪声下的任意超快速波形。我们通过实验演示了皮秒分辨率的波形的恢复，其强度比带内噪声低一个数量级以上。通过访问以前无法检测到的信息，这个概念有望推动处理弱或噪声主导的宽带波形的各个领域的发展。
