2009/12/30 by Thaddeus D. Ladd, David Press, Kristiaan De Greve +7
Physics and Astronomy · #quant-ph #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.105.107401
published as Phys. Rev. Lett. 105, 107401 (2010) · 4 pages, 3 figures
arxiv created 2009/12/30 · arxiv updated 2013/05/29
We report the observation of a feedback process between the nuclear spins in a single charged quantum dot and its trion transition, driven by a periodic sequence of optical pulses. The pulse sequence intersperses off-resonant ultrafast pulses for coherent electron-spin rotation and resonant narrow-band optical pumping. The feedback manifests as a hysteretic triangle-like pattern in the free-induction-decay of the single spin. We present a simple, quasi-analytic numerical model to describe this observation, indicating that the feedback process results from the countering effects of optical nuclear pumping and nuclear spin-diffusion inside the quantum dot. This effect allows dynamic tuning of the electron Larmor frequency to a value determined by the pulse timing, potentially allowing more complex coherent control operations.