Sutcliffe Erica, Kazmierczak Nathanael P, Hadt Ryan G
Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.
Science. 2024 Nov 22;386(6724):888-892. doi: 10.1126/science.ads0512. Epub 2024 Nov 7.
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.
顺磁分子的可调谐性和空间精度使其在量子传感方面具有吸引力。然而，传统的基于微波的检测方法具有较差的时间和空间分辨率，而与室温溶液兼容的光学方法一直难以实现。在本研究中，我们利用泵浦-探测偏振光谱来初始化和跟踪分子中的电子自旋相干。六氯铱酸钾（IV）水溶液设计用于有效地将自旋与光耦合，能够在室温及微摩尔浓度下检测几皮秒的自由感应衰减。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多达五个数量级，使得在传统技术下仅在25开尔文以下表现出相干性的系统中观察分子电子自旋相干成为可能。
