Research Updates

May 2018

Exciton Polaritons in a Two-Dimensional Lieb Lattice with Spin-Orbit Coupling

We study exciton polaritons in a two-dimensional Lieb lattice of micropillars. The energy spectrum of the system features two flat bands formed from S and Px;y photonic orbitals, into which we trigger bosonic condensation under high power excitation .....

Read More

April 2018

Thin Al1-x GaxAs0.56Sb0.44 Diodes With Low Excess Noise

Thin avalanche layers have been adopted to achieve low excess noise and high-gain bandwidth products in InP and InAlAs avalanche photodiodes. In this paper, we report the excess noise characterization in a series of Al1-xGaxAs0.56 Sb0.44 (x = 0, 0.05, 0.1, 0.15) diodes with avalanche layer thickness of 110-116 nm .....

Read More

March 2018

A quantum light-emitting diode for the standard telecom window around 1,550nm

Single photons and entangled photon pairs are a key resource of many quantum secure communication and quantum computation protocols, and non-Poissonian sources emitting in the low-loss wavelength region around 1,550nm are essential for the development of fibre-based quantum network infrastructure. However, reaching this wavelength window has been challenging for semiconductor-based quantum light sources .....

Read More

January 2018

Hybrid gap plasmon GaAs nanolasers

Compact semiconductor lasers with sub-wavelength-scale dimensions rely heavily on materials with low surface recombination due to the large surface area to volume ratios of their nano-cavities. Furthermore, the reliance on semiconductor nanostructures has led to predominantly bottom-up fabrication approaches, which has hindered scalable and practical applications. In this letter, we present lithographically constructed hybrid gap plasmon nanolasers using the gain of bulk GaAs operating at room temperature .....

Read More

January 2018

Tunable, CW Laser Emission at 225 nm via Intracavity Frequency Tripling in a Semiconductor Disk Laser

Numerous applications would benefit from a compact laser source with tunable, continuous-wave emission in the deep ultraviolet (wavelengths <;250 nm); however, very few laser sources have been demonstrated with direct emission in this spectral region and options are generally limited to pulsed, fixed wavelength sources or complex and impractical setups for nonlinear frequency mixing of the emission of several infrared lasers in various external enhancement cavities .....

Read More

December 2017

Improving a Solid-State Qubit through an Engineered Mesoscopic Environment

A controlled quantum system can alter its environment by feedback, leading to reduced-entropy states of the environment and to improved system coherence .....

Read More

December 2017

Transmission electron microscopy of AlGaAs/GaAs quantum cascade laser structures

Quantum cascade lasers can be efficient infrared radiation sources and consist of several hundreds of very thin layers arranged in stacks that are repeated periodically. Both the thicknesses of the individual layers as well as the period lengths need to be monitored to high precision .....

Read More

September 2017

Polariton Pattern Formation and Photon Statistics of the Associated Emission

We report on the formation of a diverse family of transverse spatial polygon patterns in a microcavity polariton fluid under coherent driving by a blue-detuned pump. Patterns emerge spontaneously as a result of energy-degenerate polariton-polariton scattering from the pump state to interfering high-order vortex and antivortex modes, breaking azimuthal symmetry .....

Read More

August 2017

Electron transport lifetimes in InSb/Al1-xInxSb quantum well 2DEGs

We report magnetotransport measurements of InSb/Al1-xInxSb modulation doped quantum well (QW) structures and the extracted transport (tau(t)) and quantum (tau(q)) lifetime of carriers at low temperature (<2 K). D G Hayes, C P Allford, G V Smith, C McIndo, L A Hanks, A M Gilbertson, L F Cohen, S Zhang, E M Clarke, P D Buckle. Semicond.Sci.Technol. 32, 085002 (8pp) (2017).

Read More

August 2017

Universal Growth Scheme for Quantum Dots with Low Fine-Structure Splitting at Various Emission Wavelengths

Efficient sources of individual pairs of entangled photons are required for quantum networks to operate using fiber-optic infrastructure. Joanna Skiba-Szymanska, R. Mark Stevenson, Christiana Varnava, Martin Felle, Jan Huwer, Tina Müller, Anthony J. Bennett, James P. Lee, Ian Farrer, Andrey B. Krysa, Peter Spencer, Lucy E. Goff, David A. Ritchie, Jon Heffernan, and Andrew J. Shields. PhysRevApplied, 8, 014013 (2017).

Read More