Stuttgart 2012 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 45: SYPC: From Atoms to Photonic Circuits 2

Q 45.1: Invited Talk

Thursday, March 15, 2012, 14:00–14:30, V47.01

Coherent population trapping in quantum dot molecules — Katharina Weiss, Jeroen Elzerman, and •Atac Imamoglu — ETH, Zurich, Switzerland

Low-frequency atomic transitions that are insensitive to magnetic fields play a fundamental role in precision measurements and metrology. In contrast, most solid-state quantum systems are subject to either strong electric or magnetic field fluctuations that severely limit their T2*coherence time. In this talk, we will describe experiments where we demonstrate that by adjusting the applied bias voltage and the magnetic field, spin singlet and triplet ground states of an optically active quantum dot molecule can be rendered insensitive to both electric and magnetic field fluctuations. By using coherent population trapping on transitions to a common optically excited state, we show that the singlet-triplet T2* time can exceed 100 nanoseconds. The rich optical spectrum of this quantum system exhibiting recycling transitions for spin measurements and indirect excitons for spin-state dependent long-range dipole-dipole interactions, potentially allow for applications in quantum information processing.