Practical quantum devices at Lancaster
Welcome to the home of the Quantum Electro-Optics group at Lancaster University. We are a team of experimental physicist driven by a passion to develop practical technologies and applications of quantum information. Our research incorporates material design, growth, processing, measurement and integration. We are part of Lancaster's new Quantum Technology Centre, which contains an extensive suite of world-class facilities. Our aim is to help to create integrated photonic structures, to realise a “toolbox” of versatile quantum devices, from which an endless array of quantum systems could be constructed and mass-produced.
Epitaxial growth of III-V semiconductors
At Lancaster we have four molecular beam epitaxy
growth (MBE) chambers that are capable of tailoring
semiconductor structures, building them one layer of atoms at a time. The picture above shows one of our machines (Veeco V80), which is configured to grow arsenides and antimonides. To the right is an image showing one of the unique structures we're able to grow; it is a cross-section through a GaSb quantum ring, embedded in GaAs. The bright dots in the picture are individual antimony atoms (the picture was taken with STM at Eindhoven). These particular structures are exciting as they exhibit quantum properties above room temperature!
Optoelectronic device processing
To create three-dimensional devices incorporating the epitaxial layers and nanostructures by MBE we have a class 100/1000 cleanroom facility, including a JEOL electron beam lithography system.
(image ©M. Thompson 2013)
In the cleanroom we create photonic structures which harness the quantum properties of the nanostructures at their core, but that can be addressed macroscopically.
This allows us to study the fundamental physics at the heart of these robust devices, as well as incorporate them into real world applications.
Quantum electro-optic measurements
The quantum devices created in our cleanroom facility are packaged, and then their fundamental electronic and optical properties are studied in a versatile quantum electro-optics laboratory, shown in the picture to the right.
This laboratory contains a helium-free cryostat, allowing optical and electronic access to a sample held in a vacuum at a temperature anywhere between 12 and 300 K. Whilst the end-goal of this research is to create systems that will operate above room temperature, being able to study devices at very low temperatures often elucidates the physical processes driving their behavior.
Fast electronics, and a pulsed laser (ps) that can be tuned from the visible to the infrared, can be used to excite and manipulate the devices being studied. Optical emission is collected and analysed either through a spectrometer, or fed into single-channel photon detectors.
(image ©M. Thompson 2013)