Maiken Mikkelsen, University of California, Berkeley
Abstract
Individual semiconductor quantum dots are attractive systems for the study of fundamental spin dynamics, light-matter interactions, and quantum information applications. A key ingredient for spin-based quantum information processing is the coherent rotation of a spin-state on timescales much faster than the spin coherence time. To achieve this, off-resonant optical pulses are used to create a large effective magnetic field via the optical Stark effect, allowing the coherent rotation of a single electron spin in a quantum dot through arbitrary angles up to pi radians in 30 ps [1]. Non-destructive time-resolved Kerr rotation is used to directly monitor the electron spin dynamics and in addition serves as a sensitive probe of the local nuclear spin environment [2,3]. These experiments demonstrate the sequential initialization, ultrafast manipulation, and detection of a single electron spin in GaAs quantum dot. One of the next challenges for quantum information applications is the creation of on-chip quantum networks. A step towards this goal is the integration of single emitters with nanophotonic structures. Recent experiments demonstrate efficient coupling of a single CdSe/ZnS quantum dot to a deep-subwavelength waveguide revealing strongly enhanced light-matter interactions [4]. These results represent progress towards the implementation of scalable quantum
information processing in the solid state.
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