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Quantum Optoelectronics

WebpictureRTP
Quantum control in semiconductors: the first experimental demonstration of adiabatic inversion in a semiconductor quantum dot. The apparatus is shown schematically (top left) and the microscope is shown in the photo. Results for measured exciton ionisation current are shown (bottom left) with a theoretical model (bottom right).

Quantum-dynamical routes to Bose-Einstein condensation in solids

We are currently exploring experimental routes to test a theoretical prediction of a form of Bose-Einstein condensation in a semiconductor polariton system, which should arise from the quantum dynamics in specially-prepared arrangement of quantum dots interacting with a microcavity optical mode. The first step has been the experimental demonstration, for the first time, of inversion of optical transitions in quantum dots by the process of adiabatic rapid passage (as illustrated). Current work is extending this to ensembles of dots, and high densities of dots in semiconductor microcavities.

Exciton spin fine structure in quantum dots

A unique method for observing the spin fine structure in semiconductor quantum dots has been devised as a function of magnetic field, from 0-12 Tesla, in an arbitrary orientation. This allows full access to details of the g-factor tensors of the electron and hole, and information about the electron-hole correlation length through the diamagnetic behaviour. We are currently occupied with a challenging project to add a much greater knowledge of the physical structure of the same dots, in order to provide the most stringent tests of theoretical models.