We seek a motivated PhD student to study the interactions, scattering and emission of quantum light within solid state devices. Photons are ideal carriers of quantum information, being fast, cheap and easy to encode with quantum-information carried in their polarisation, phase, time or path degrees of freedom. The challenge in developing useful applications of optical quantum technology is to demonstrate an advantage over classical systems when sources and detectors are not perfect. Applications in low light level imaging, secure communications and quantum computing are likely for the devices you will develop. Amongst solid state quantum emitters, Indium-Gallium-Arsenide quantum dots offer the highest efficiency and purity but only at cryogenic temperatures [1,2]. However, emitters in wide-bandgap materials, such as diamond and boron-nitride offer the unique capability to emit quantum light at room temperature.
The focus of the project will be on increasing the efficiency, purity and repetition rate of single photon sources using novel designs of microcavity to alter the emission characteristics of the device. In year 1 of this project you will design microcavities using a commercial photonics software package and create structures in the Institute for Compound Semiconductors cleanroom at Cardiff University. In Year 2 you will optimise the photon collection apparatus to be portable, stable and efficient. You will use our new superconducting single photon detectors, which have detection efficiency over 85% to single photons, to characterise your devices. In year 3 you define and develop prototype systems to that demonstrate a quantum advantage over equivalent classical devices.
 “Near-optimal single-photon sources in the solid state”, N. Somachi et al, Nature Photonics 10, 340–345 (2016)
 “Cavity-enhanced coherent light scattering from a quantum dot” A J. Bennett et al, Science Advances 2016: e1501256
Optical characterisation will be carried out in the newly established Quantum Technology labs with access to > £1M of equipment, including photo-detectors sensitive to the arrival of single photons, ultrafast electronics, high coherence lasers and cryogenic equipment. Practical lab skills will be gained including Labview programming, error analysis and data processing.
In addition, you will have access to the Institute Cleanroom to fabricate samples. This is a world-class facility run by a team of skilled technicians. In 2021, the group and cleanroom will relocated to a new £100 million facility on Maindy Road, resulting in a significant expansion in lab space.
The position is within a group supervised by Dr Bennett, with the support of 2 experienced PDRA and 3 PhD students. An exceptional level of training and support to the candidate on a day to day basis in a friendly and open working environment. He/she will have a desk in an interdisciplinary research office with other Post-docs/PhD students from the schools of physics and engineering. To enable integration within the research culture of the university the he/she will attend Quantum-Team meetings (Mondays), Condensed Matter Seminars (Wednesdays) and the group Journal Club (Thursdays).
The candidate will uncover new science in a fast-moving research field, which will lead to great publications and opportunities to travel to international conferences and the main supervisor’s collaborators in the UK and EU. In addition, much sought after cleanroom fabrication skills will enhance employment opportunities.
Applicants should submit an application for postgraduate study via the Cardiff University webpages (http://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/engineering
• an upload of your CV
• a personal statement/covering letter
• two references
• Current academic transcripts
Applicants should select Doctor of Philosophy (Engineering), with a start date of October 2020.
In the research proposal section of your application, please specify the project title and supervisors of this project and copy the project description in the text box provided. In the funding section, please select "I will be applying for a scholarship / grant" and specify that you are applying for advertised funding, reference AB-DTP-2020
Candidates should hold a good bachelor’s degree (first or upper second-class honours degree) or a MSc degree in Physics or Engineering who has particular interest in optics, solid state physics and/or quantum technology.
Applicants whose first language is not English will be required to demonstrate proficiency in the English language (IELTS 6.5 or equivalent)