Mostafavi Fatemeh, Jafari Zeinab, Lollie Michelle L J, You Chenglong, De Leon Israel, Magaña-Loaiza Omar S
Quantum Photonics Laboratory, Department of Physics & Astronomy, Louisiana State University, Baton Rouge 70803, LA, USA.
School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey, Nuevo Leon 64849, Mexico.
Nanophotonics. 2022 Jun 15;11(14):3299-3306. doi: 10.1515/nanoph-2022-0160. eCollection 2022 Jul.
The possibility of using weak optical signals to perform sensing of delicate samples constitutes one of the main goals of quantum photonic sensing. Furthermore, the nanoscale confinement of electromagnetic near fields in photonic platforms through surface plasmon polaritons has motivated the development of highly sensitive quantum plasmonic sensors. Despite the enormous potential of plasmonic platforms for sensing, this class of sensors is ultimately limited by the quantum statistical fluctuations of surface plasmons. Indeed, the fluctuations of the electromagnetic field severely limit the performance of quantum plasmonic sensing platforms in which delicate samples are characterized using weak near-field signals. Furthermore, the inherent losses associated with plasmonic fields levy additional constraints that challenge the realization of sensitivities beyond the shot-noise limit. Here, we introduce a protocol for quantum plasmonic sensing based on the conditional detection of plasmons. We demonstrate that the conditional detection of plasmonic fields, via plasmon subtraction, provides a new degree of freedom to control quantum fluctuations of plasmonic fields. This mechanism enables improvement of the signal-to-noise ratio of photonic sensors relying on plasmonic signals that are comparable to their associated field fluctuations. Consequently, the possibility of using weak plasmonic signals to sense delicate samples, while preserving the sample properties, has important implications for molecule sensing, and chemical detection.
利用微弱光信号对精细样品进行传感的可能性构成了量子光子传感的主要目标之一。此外，通过表面等离激元极化激元在光子平台中实现电磁近场的纳米级限制，推动了高灵敏度量子等离激元传感器的发展。尽管等离激元平台在传感方面具有巨大潜力，但这类传感器最终受到表面等离激元量子统计涨落的限制。事实上，电磁场的涨落严重限制了量子等离激元传感平台的性能，在这些平台中，精细样品是通过微弱近场信号来表征的。此外，与等离激元场相关的固有损耗带来了额外的限制，对实现超越散粒噪声极限的灵敏度构成了挑战。在此，我们介绍一种基于等离激元条件检测的量子等离激元传感方案。我们证明，通过等离激元减法对等离激元场进行条件检测，为控制等离激元场的量子涨落提供了一个新的自由度。这种机制能够提高依赖于与相关场涨落相当的等离激元信号的光子传感器的信噪比。因此，在保持样品特性的同时，利用微弱等离激元信号对精细样品进行传感的可能性，对分子传感和化学检测具有重要意义。
