The tunability and spatial precision of paramagnetic molecules makes them attractive for quantum sensing. However, usual microwave-based detection methods have poor temporal and spatial resolution, and optical methods compatible with room-temperature solutions have remained elusive. In this study, we utilized pump-probe polarization spectroscopy to initialize and track electron spin coherence in a molecule. Designed to efficiently couple spins to light, aqueous potassium hexachloroiridate(IV) enabled detection of few-picosecond free-induction decay at room temperature and micromolar concentrations. Viscosity was found to strongly vary decoherence lifetimes. This approach has improved the experimental time resolution by up to five orders of magnitude, making it possible to observe molecular electron spin coherence in a system that only exhibits coherence below 25 kelvin with traditional techniques.

中文翻译：

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室温水溶液中分子电子自旋的超快全光学相干性


顺磁性分子的可调性和空间精度使其对量子传感具有吸引力。然而，通常基于微波的检测方法的时空分辨率较差，并且与室温解决方案兼容的光学方法仍然难以捉摸。在这项研究中，我们利用泵浦探针极化光谱来初始化和跟踪分子中的电子自旋相干性。六氯虹酸钾 （IV） 水溶液旨在有效地将自旋与光耦合，能够在室温和微摩尔浓度下检测几皮秒的自由诱导衰变。发现粘度会强烈改变退相干寿命。这种方法将实验时间分辨率提高了五个数量级，从而可以在传统技术仅表现出低于 25 开尔文的相干性的情况下观察到分子电子自旋相干性。