Department of Electrical and Computer Engineering, Institute for Research in Electronics and Applied Physics, and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, United States.
Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States.
Nano Lett. 2023 Mar 8;23(5):1781-1786. doi: 10.1021/acs.nanolett.2c04552. Epub 2023 Feb 27.
Noise spectroscopy elucidates the fundamental noise sources in spin systems, thereby serving as an essential tool toward developing spin qubits with long coherence times for quantum information processing, communication, and sensing. But existing techniques for noise spectroscopy that rely on microwave fields become infeasible when the microwave power is too weak to generate Rabi rotations of the spin. Here, we demonstrate an alternative all-optical approach to performing noise spectroscopy. Our approach utilizes coherent Raman rotations of the spin state with controlled timing and phase to implement Carr-Purcell-Meiboom-Gill pulse sequences. Analyzing the spin dynamics under these sequences enables us to extract the noise spectrum of a dense ensemble of nuclear spins interacting with a single spin in a quantum dot, which has thus far been modeled only theoretically. By providing spectral bandwidths of over 100 MHz, our approach enables studies of spin dynamics and decoherence for a broad range of solid-state spin qubits.
噪声光谱学阐明了自旋系统中的基本噪声源，因此是开发具有长相干时间的用于量子信息处理、通信和传感的自旋量子位的重要工具。但是，当微波功率弱到无法产生自旋的拉比旋转时，依赖于微波场的噪声光谱学现有技术就变得不可行。在这里，我们展示了一种替代的全光学方法来进行噪声光谱学研究。我们的方法利用受控定时和相位的相干拉曼旋转来实现 Carr-Purcell-Meiboom-Gill 脉冲序列。分析这些序列下的自旋动力学使我们能够提取与量子点中的单个自旋相互作用的密集核自旋 ensemble 的噪声谱，迄今为止，这仅在理论上进行了建模。通过提供超过 100 MHz 的光谱带宽，我们的方法能够研究广泛的固态自旋量子位的自旋动力学和退相干。
