EPSRC CDT in Metamaterials (PhD studentship): All-optical metasurface modulators for THz radiation Ref: 2834

About the award

The studentship is part of the UK’s Centre of Doctoral Training in Metamaterials (XM2) based in the Departments of Physics and Engineering on the Streatham Campus in Exeter.  Its aim is to undertake world-leading research, while training scientists and engineers with the relevant research skills and knowledge, and professional attributes for industry and academia.

XM2 studentships are of value around £90,000, which includes £11,000 towards the research project (travel, consumables, equipment etc.), tuition fees, and an annual, tax-free stipend of approximately £14,500 per year for UK/EU students.

In addition, due to its industry partner this project attracts a top up of a further £2,000 per year.

Exeter has a well-established and strong track record of relevant research, and prospective students can consider projects from a wide variety of fields:

  • Acoustic and Fluid-dynamical Metamaterials
  • Biological and Bio-inspired Metamaterials
  • Graphene and other 2D Materials, and related Devices
  • Magnonics, Spintronics and Magnetic Metamaterials
  • Microwave Metamaterials
  • Nanomaterials and Nanocomposites
  • Optical, Infra-red and THz Photonics and Plasmonics
  • Quantum Metamaterials
  • Wave Theory and Spatial Transformations

Please visit www.exeter.ac.uk/metamaterials to learn more about our centre and see the full list of projects that we have on offer this year.

International students are welcome to apply: fees and project costs will be paid, but the stipend can only be provided in exceptional circumstances.  We encourage international scholarship applicants or recipients to contact us directly prior to making their application (metamaterials@exeter.ac.uk).

Statement of Research

Joint supervisors: Euan Hendry, David Phillips

Industrial supervisors: Terence Wall (Q-EYE Technology)

The ability to control and manipulate THz radiation has been a long-term goal in electromagnetic
research. For this spectral band, all-optical modulation is a convenient mechanism to utilize: here,
one relies on the change in conductivity induced in a high mobility semiconductor when excited by
optical light. This process is very fast, with pico to micro-second switching times, depending on the
semiconductor. However, it can also be rather inefficient, often requiring very intense CW light
sources or femotosecond pulses.

To increase the effectiveness of all-optical modulators, one can employ the resonant enhancement
of antennas or cavities [see Applied Spectroscopy Reviews 50, 707 (2015) and references there-in].
For example, optically induced modulation of THz radiation has been demonstrated, where
patterned photoexcitation of a semiconductor using a continuous wave laser source allowed tuning
of localised surface plasmons resonances [Optic. Express 37, 1391 (2012)]. Alternatively, metallic
resonators can be used on a semiconductor surface, as in refs. [Nat. Comm. 3, 1151 (2012)] and [PRB
75, 235305 (2007)], to create a “metasurface” photo-modulator. This form of modulators is
particularly promising, as they are predicted to enhance the modulation efficiency by up to two
orders of magnitude in very low loss environments [PRB 75, 235305 (2007)].

The goal of this PhD project is to design, characterise and optimise meta-surface modulators for
specific THz frequency bands, and working with Q-Eye personnel, to trial as part of the multiplexing
system of Q-Eye’s high performance sensor. We will begin by considering designs similar to those in
[Nat. Comm. 3, 1151 (2012)], featuring resonant antenna arrays on a semiconductor surface. We
will also consider matching resonant etalon effects, and even doubly resonant surfaces on both the
front and rear surfaces [APL 104, 103508 (2014)]. Dimensions and structures will need to be
optimised to provide narrow resonances (aiming for <10% bandwidth), while exhibiting relatively
low angular dependence and low emissivity. Simultaneously, the student will consider the best
semiconducting materials for the modulator itself, including high mobility 2-DEG materials, assessing
both the modulation magnitude and switching times. Strained and unstrained Si and Ge, of great
interest to Q-Eye, and whose staff have extensive experience of these materials, will be investigated.
Fast and efficient modulators are crucial to many imaging and signal processing applications, and the
optimised designs from the project will be incorporated into THz imaging modalities.

About XM2

Metamaterials are fabricated microstructures having properties beyond those found in nature. They are an important new class of electromagnetic and acoustic materials with applications in many technology areas: energy storage and improved efficiency, imaging, communications, sensing and the much-hyped ‘cloaking’. Having recruited nearly 70 new PhD researchers in its first four years, the EPSRC Centre for Doctoral Training (XM2) hosted by the University of Exeter (www.exeter.ac.uk/metamaterials) will admit its fifth cohort of PhD students in September 2018.

The first year of the studentship includes an assessed, stand alone project, and a substantial programme of training. Students will choose from a wide range of taught modules, and participate in academic and personal development skills-based workshops, together with creativity events and conference-style meetings. The cohort will also be expected to disseminate their results to the international community via high-impact publications and international conferences. They will spend time working with our academic and industrial partners.  Full details of the programme are available here, or download a copy of our prospectus.

The University of Exeter combines world class research with excellent student satisfaction. It is a member of the Russell Group of leading research-intensive universities. Formed in 1955, the University has over 20,000 students from more than 130 different countries. Its success is built on a strong partnership with its students and a clear focus on high performance. Recent breakthroughs to come out of Exeter's research include the identification and treatment of new forms of diabetes and the creation of the world's most transparent, lightweight and flexible conductor of electricity. Exeter is ranked amongst the UK’s top 10 universities in the Higher Education league tables produced by the Times and the Sunday Times. It is also ranked amongst the world’s top 200 universities in the QS and Times Higher Education rankings.

Summary

Application deadline:31st January 2018
Number of awards:1
Value:Approximately £90,000, including research and travel budget, tuition fees and stipend (approximately [£14,500/£16,500] payable to UK or EU students only)
Duration of award:per year
Contact: Prof. Alastair Hibbins (Admissions Tutor)metamaterials@exeter.ac.uk

How to apply

Application criteria

During the application process you will need to upload the documents listed below. Please prepare these before starting the application process.

  • A statement describing why you would like to study for a PhD in Physics or Engineering,
  • A statement describing why you are considering a PhD programme that offers a cohort-based doctoral training model,
  • An academic CV,
  • A cover letter that discusses your preferred area(s) of study and/or your interest in a particular project/supervisor,
  • A document outlining your research interests and any relevant expertise,
  • Degree transcript(s) giving information about the qualification awarded, the modules taken during the study period, and the marks for each module taken,
  • The contact details of two academic referees.

Please note that of all the projects advertised we expect, as a Centre, to fill 15-20 posts only.

Shortlisting and interviews

Applications will be reviewed by members of the XM2 management board and candidates will be short-listed against a set of agreed criteria to ensure quality while maintaining diversity. Failure to include all the the elements above may result in rejection. Criteria will include:

ESSENTIAL

  • Excellence in a lower degree in a relevant discipline;
  • Excellence in written and oral skills in English;
  • Evidence of knowledge of XM2 ethos, research themes and/or supervisors.

DESIRABLE

  • Specialist knowledge about one or more XM2 topics;
  • Research outputs (e.g. papers) and/or has undertaken training in research methodology (e.g. undergraduate research projects);
  • Ability to work collaboratively

Short-listed candidates will be interviewed by a panel of two academic members of staff drawn from the management board. If successful, a second interview will be undertaken by the potential academic supervisors for the student concerned. Offers are normally made shortly after a successful second interview.