Principal Investigator: Dr Andrew Shields
The Project
Semiconductor Nanotechnology
The goal of this project is to investigate the possibility of using semiconductor quantum dots and impurity atoms in optical cavities as quantum memories.
Quantum dots are tiny disks of semiconductor material tens of nanometers in diameter and a few nanometers in height fabricated onto a larger substrate material with a larger bandgap. The confining barriers of a quantum dot restrict electronic motion such that they have properties not seen in larger scale semiconductor structures. For example, confinement of electrons results in sharp spectral lines similar to those of atoms, in direct contrast to the broad lines typical of large scale semiconductors in which electrons can have a wide range of energies. Due to their small size quantum dots can hold only a small number of electrons, providing a natural structure for single photon storage and detection: a prerequisite of many ideas to exploit the quantum mechanical nature of light. Qubits could be encoded in the spin of an excess electron in a quantum dot.
This project will develop methods of efficiently coupling single photons into and out from quantum dots. The Zeeman structure of individual quantum dots will be investigated in detail. Long term aims include demonstration of storage of weak optical pulses and single photons in quantum dot devices with development of schemes for qubit read-out on demand.
List of Publications
QAP
A. J. Bennett, P. Atkinson, P. See et al, Single-photon-emitting diodes: a review, Phys. Status Solidi b 243 3730 (2006) quant-ph/0610264
D. J. P. Ellis, A. J. Bennett, A. J. Shields, P. Atkinson and D. A. Ritchie, Electrically addressing a single self-assembled quantum dot, Applied Phys. Letters 88 133509 (2006)
R. M. Stevenson, R. J. Young, P. Atkinson et al, A semiconductor source of triggered entangled photon pairs, Nature 439 179 (2006)
R. M. Stevenson, R. J. Young, P. Atkinson et al, Control of Exciton Fine Structure Splitting in Quantum Dots, Acta Phys. Polonica A 110 311 (2006)
R. J. Young, R. M. Stevenson, P. Atkinson et al, Improved fidelity of triggered entangled photons from single quantum, New J. Phys. 8 29 (2006) quant-ph/0601187
R. J. Young, S. J. Dewhurst, R. M. Stevenson et al., Controlling the polarization correlation of photon pairs from a charge-tuneable quantum dot, submitted to Appl. Phys. Lett.
R. J. Young, D. J. P. Ellis, R. M. Stevenson et al., Quantum Dot Sources for Single Photons and Entangled Photon Pairs, accepted for publication in Proc. IEEE
R. J. Young, D. J. P. Ellis, R. M. Stevenson et al., Quantum light generation with a semiconductor quantum dot, Proc. IEEE 6468 40 (2007)
R. M. Stevenson, A. J. Hudson, R. J. Young et al., Biphoton interference with a quantum dot entangled light source, Optics Express 15 6507 (2007)
A. J. Bennett, D. J. P. Ellis, A. J. Shields et al, Oxide-semiconductor micro-pillar cavities, accepted for publication in Phys. E
A. J. Bennett, D. G. Gevaux, Z. Yuan et al, Position-time entanglement with degenerate single photons from a quantum dot (2007)
D. J. P. Ellis, A. J. Bennett, A. J. Shields, P. Atkinson, I. Farrer, D. A. Ritchie, Oxide-apertured microcavity single-photon emitting diode, Appl. Phys. Lett. 90 233514 (2007)
M. B. Ward, T. Farrow, P. See et al, Electrically driven telecom wavelength single photon source, Appl. Phys. Lett. 90 063512 (2007)
R. J. Young, S. J. Dewhurst, R. M. Stevenson et al., Single electron-spin memory with a semiconductor quantum dot, New J. Phys. 9 365 (2007)
R. J. Young, R. M. Stevenson, A. Hudson et al., Generating triggered single and entangled photons with a semiconductor source, IOS Press (2007) ISBN: 978-1-58603-749-9
A. J. Hudson, R. M. Stevenson, R. J. Young et al., Biphoton Interference with a quantum dot source of entangled light, accepted for publication in Phys. E
R. M. Stevenson, A. J. Hudson, A. J. Bennett et al., Evolution of entanglement within classical light states, arXiv:0803.3947
R. J. Young, R. M. Stevenson, A. J. Hudson et al., Bell-inequality violation with a triggered photon-pair source, arXiv:0804.0716
Related Work
D. J. P. Ellis, R. M. Stevenson, R. J. Young et al., Control of fine-structure splitting of individual InAs quantum dots by rapid thermal annealing, Appl. Phys. Lett. 90 011907 (2007) quant-ph/0612047
A. J. Bennett, D. J. P. Ellis, A. J. Shields et al, Observation of the Purcell Effect in high index contrast pillar microcavities, Appl. Phys.Lett. 91 191911 (2007)
A. J. Hudson, R. M. Stevenson, R. J. Young et al., Coherence of an Entangled Exciton-Photon State, Phys. Rev. Lett. 99 266802 (2008) quant-ph/0707.3556
R. J. Young, R. M. Stevenson, P. Atkinson et al., Quantum Dots in Planar Cavities - Single and Entangled Photon Sources, Springer Berlin (2008) ISBN: 978-3-540-38234-8