quantum-dot spin-state preparation with near-unity fidelity m. atatüre, j. dreiser, a. badolato, a....
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Quantum-Dot Spin-State Preparation with Near-Unity
Fidelity
M. Atatüre, J. Dreiser, A. Badolato, A. Högele,
K. Karrai, A. Imamoglou
Science 312, 551 (2006)
30.01.07
OverviewOptical controlling of spin in quantum-dots at 4 K
High fidelity spin state preparation due to Pauli blockade
Self-assembled InAs/GaAs QD
Four-Level System for B=0 , EF EF
,
Laser absorbtion
EF EFHyperfine induced spin-flip
Spontaneous spin-flip Raman scattering
Four-Level System for B>0 , EF EF
,
Laser absorbtion
EF EFHyperfine induced spin-flip
Spontaneous spin-flip Raman scattering
Four-Level System for B>0 with Repump Laser
, EF EF ,
Laser absorbtion
EF EFHyperfine induced spin-flip
Laser absorbtion
How It Works
EF
Blocked!
Results: Laser Absorption
Absorbtion due to cotunneling
Repump Laser detuned by 6 GHz (Zeeman splitting)
Absorbtion suppressed due to Pauli blockade
Linewidth of the transition X-
Results: High FidelityTheoretical model
Exponential fit
Repump Laser
Experimental data
electrons of Number Absorbtion
Conclusions and Outlook
High-fidelity spin preparation (99.8 %)
Spin cooling down to 20 mK (T=4 K)
Works for both spins
Prepare arbitrary superpostition of spin states
Tune by changing the magnetic field orientation with respect to the confinement axis
EF EF