TE/TM polarisation response of InAs/GaAs quantum dot bilayers
22 Oct 2015 | Presentation Materials | Contributor(s): Muhammad Usman
Quantum dot bilayers are strong candidates for the design of telecom devices working at 1300 nm wavelength range. Here we analyse - both experimentally and theoretically - their optical and polarisation properties.
Bismide Semiconductors: Revolutionising Telecom Lasers
19 Oct 2015 | Papers | Contributor(s): Muhammad Usman, Christopher A Broderick, Eoin P O\'reilly
Today’s telecomm lasers are plagued with Auger-related losses, which significantly reduce their efficiency and make device cooling essential. We are proposing a radical change in the laser technology by developing a new class of materials, bismide semiconductors. These novel nanomaterials...
Why quantum dot simulation domain must contain multi-million atoms?
11 Jan 2013 | Online Presentations | Contributor(s): Muhammad Usman
The InGaAs quantum dots obtained from the self-assembly growth process are heavily strained. The long-range strain and piezoelectric fields significantly modifies the electronic structure of the quantum dots. This imposes a critical constraint on the minimum size of the simulation domain to study...
Quantum Dot based Photonic Devices
01 Apr 2012 | Online Presentations | Contributor(s): Muhammad Usman
Deployment of nanometer-sized semiconductor quantum dots (QDs) in the active region ofphotonic devices such as lasers, semiconductor optical amplifiers (SOA's), photo-detectors etc.for the next generation communication systems offers unique characteristics such astemperature-insensitivity, high...
Excited State Spectroscopy of a Quantum Dot Molecule
Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum by Krenner et al (Phys. Rev. Lett. 94 057402, 2005) is quantitatively reproduced,...
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