Hovav Y, Naydenov B, Jelezko F, Bar-Gill N
Department of Applied Physics, Rachel and Selim School of Engineering, Hebrew University, Jerusalem 9190401, Israel.
Institute of Quantum Optics, Ulm University, Albert Einstein Allee 11, D-89081 Ulm, Germany.
Phys Rev Lett. 2018 Feb 9;120(6):060405. doi: 10.1103/PhysRevLett.120.060405.
It was recently demonstrated that bulk nuclear polarization can be obtained using nitrogen vacancy (NV) color centers in diamonds, even at ambient conditions. This is based on the optical polarization of the NV electron spin, and using several polarization transfer methods. One such method is the nuclear orientation via electron spin locking (NOVEL) sequence, where a spin-locked sequence is applied on the NV spin, with a microwave power equal to the nuclear precession frequency. This was performed at relatively high fields, to allow for both polarization transfer and noise decoupling. As a result, this scheme requires accurate magnetic field alignment in order preserve the NV properties. Such a requirement may be undesired or impractical in many practical scenarios. Here we present a new sequence, termed the refocused NOVEL, which can be used for polarization transfer (and detection) even at low fields. Numerical simulations are performed, taking into account both the spin Hamiltonian and spin decoherence, and we show that, under realistic parameters, it can outperform the NOVEL sequence.
最近有研究表明，即使在环境条件下，利用金刚石中的氮空位（NV）色心也能实现体核极化。这是基于NV电子自旋的光极化，并采用了几种极化转移方法。其中一种方法是通过电子自旋锁定（NOVEL）序列进行核取向，即在NV自旋上应用自旋锁定序列，微波功率等于核进动频率。这是在相对较高的磁场下进行的，以实现极化转移和噪声去耦。因此，该方案需要精确的磁场对准以保持NV特性。在许多实际场景中，这样的要求可能是不理想的或不切实际的。在此，我们提出了一种新的序列，称为重聚焦NOVEL，即使在低场下也可用于极化转移（和检测）。我们进行了数值模拟，同时考虑了自旋哈密顿量和自旋退相干，结果表明，在实际参数下，它的性能优于NOVEL序列。
