Journal of Physical Chemistry & Biophysics
Open Access

Suppression of phonon-mediated dephasing in adiabatic rapid passage on a single semiconductor quantum dot

2^nd International Conference and Exhibition on Lasers, Optics & Photonics

September 08-10, 2014 Hilton Philadelphia Airport, USA

Kimberley C Hall, Reuble Mathew, Eric Dilcher, Angela Gamouras, Ajan Ramachandran, Sabine Freisem and Dennis Deppe

Scientific Tracks Abstracts: J Phys Chem Biophys

Abstract :

The ease and efficiency of coherent optical control of fundamental charge and spin states in semiconductor quantum dots (QDs) makes these materials promising for realizing the building blocks of a solid state quantum computer. Optimal quantum control techniques may be used to tailor the QD-light coupling, providing a direction for optimizing the speed and fidelity of elementary quantum gates as well as the pursuit of complex-instruction-set quantum computing. This potential was recently illustrated through the application of femtosecond pulse shaping to the theoretical optimization of a C-ROT gate in a single QD, and the experimental demonstration of a parallel single qubit gate involving two qubits in distant quantum dots. Here we report the demonstration of adiabatic rapid passage (ARP) on a single semiconductor QD. Through the application of femtosecond pulse shaping techniques to broad-bandwidth control pulses, we achieve a 20-fold reduction in the gate time for ARP in comparison to previous work. Our experiments also explore a new regime of strong and rapidly-varying Rabi energies, which we exploit to gain new insight into electron-phonon coupling. Our experiments show that the exciton inversion efficiency depends on the sign of the pulse chirp, with a suppression of resonant coupling to acoustic phonons for positive pulse chirp at low temperatures.

Biography :

Kimberley C Hall completed her PhD at the University of Toronto in 2002, followed by Postdoctoral studies at the University of Iowa. Since 2004, he has been a faculty member in the Department of Physics and Atmospheric Science at Dalhousie University and holds a position of Canada Research Chair in Ultrafast Science. At Dalhousie University, he directs a research group focused on ultrafast spectroscopy and quantum control in semiconductor materials.