Carter S G, Shabaev A, Economou Sophia E, Kennedy T A, Bracker A S, Reinecke T L
Naval Research Laboratory, Washington, D.C. 20375-5322, USA.
Phys Rev Lett. 2009 Apr 24;102(16):167403. doi: 10.1103/PhysRevLett.102.167403.
We find that detuning an optical pulse train from electronic transitions in quantum dots controls the direction of nuclear spin flips. The optical pulse train generates electron spins that precess about an applied magnetic field, with a spin component parallel to the field only for detuned pulses. This component leads to asymmetry in the nuclear spin flips, providing a way to stabilize and control the nuclear spin polarization. This effect is observed using two-color, time-resolved Faraday rotation and ellipticity.
我们发现，使光脉冲序列与量子点中的电子跃迁失谐，可控制核自旋翻转的方向。光脉冲序列产生的电子自旋会绕着外加磁场进动，只有失谐脉冲的自旋分量才与磁场平行。该分量导致核自旋翻转的不对称性，提供了一种稳定和控制核自旋极化的方法。利用双色、时间分辨法拉第旋转和椭圆率可观察到这种效应。
