Theory of quantum state control in photon-electron-nucleus coupled system

在金刚石中Si：P和NV心的系统中，光学上实现了核自旋极化，但尚未实现理想的自旋极化。本文提出了一种在一般中性施主体系中实现原子核理想自旋极化的光学方法。首先，施主电子的自旋极化可以通过自旋单重态施主束缚激子态光学实现。然后，自旋三重态激子状态被光学激发，并且该状态转变为自旋单重态激子状态，从而通过超精细相互作用翻转供体核的自旋。这一过程不以详细平衡为基础，可以通过重复的光激发实现原子核的完美自旋极化

The nuclear spin polarization is realized optically in the system of Si:P and NV center in diamond but the perfect spin polarization is not yet achieved. Here we proposed an optical method to realize the perfect spin polarization of the nucleus in the general neutral donor system. First of all, the spin polarization of the donor electron can be realized optically through the spin-singlet donor-bound exciton state. Then the spin-triplet exciton state is optically excited and this state makes a transition to the spin-singlet exciton state thereby flipping the spin of the donor nucleus through the hyperfine interaction. This process is not based on the detailed balance and can achieve the perfect spin polarization of the nucleus by repetitive optical excitation