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Award details

University of Exeter funding: All-dielectric beam control

CDT in Metamaterials: Beaming light in new directions - metasurfaces for tuneable control of optics Ref: 3449

About the award

All-dielectric beam control using dynamically-tuneable metasurfaces

Statement of Research

Joint supervisors: Prof C David Wright and Dr Isaac Luxmoore

External partner: DSTL

In recent years, electromagnetic metasurfaces have generated huge interest due to their ability for precise control of the amplitude, phase and polarisation of waves, from the microwave region right through to the optical part of the spectrum. Indeed, optical metasurfaces can mimic the wavefront manipulation capabilities of conventional optics, without the need for bulky optical components or any moving parts. A variety of optical and photonic metadevices for wavefront shaping, such as flat lenses, hologram generators and beam steerers have been reported. However, in such approaches device operation is essentially fixed-by-design, making them unsuitable for applications where light needs to be controlled dynamically. However, by combining metasurface concepts with active materials whose refractive index can be selectively (user) controlled, we can provide hitherto un-realised and real-time dynamic control of the metasurface properties, leading to the provision of new and enhanced functionality.

One class of suitable active materials is the chalcogenide phase-change alloys (PCMs), the development and application of which Exeter is internationally leading (see e.g. [1-3]). PCMs possess the ability to be switched quickly (nanoseconds or less) and repeatedly (billions of times) between amorphous and crystalline states (or indeed to an intermediate state between the two) by an appropriate thermal, optical or electrical stimulus – with the different phase-states possessing strikingly different optical properties (very large contrast in real and imaginary parts of the refractive index). Thus, by integrating PCMs with optical metasurfaces we can provide a form of continuously tuneable dielectric whose refractive index can be user-controlled via appropriate (electrical, thermal or optical) excitation. This opens-up exciting new possibilities for provision of active, dynamic and re-configurable photonic devices including – one focus of this PhD project – compact, low-power, high-efficiency optical beam steering devices with moving parts. The development of such devices would open up a new route to a variety of exciting applications, such as imaging and detection systems for security and defence, LIDAR scanning systems for autonomous vehicles, robotics and sensing, free space and surface wave optical signal coupling.

[1] Hosseini P, Wright CD, Bhaskaran H. (2014) An optoelectronic framework enabled by low-dimensional phase-change films, Nature, volume 511, no. 7508, pages 206-211, DOI:10.1038/nature13487
[2] Cheng Z, Ríos C, Youngblood N, Wright CD, Pernice WHP, Bhaskaran H. (2018) Device-Level Photonic Memories and Logic Applications Using Phase-Change Materials, Adv Mater, volume 30, DOI:10.1002/adma.201802435
[3] C R De Galarreta et al., Nonvolatile Reconfigurable Phase-Change Metadevices for Beam Steering in the Near Infrared, Adv Func Mater, DOI:10.1002/adfm.201704993 (2018)

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.  Our 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.

The 4 year studentship (value approx. £105,000) is externally funded by an industry partner. It is of value around £105,000, which includes £13,000 towards the research project (travel, consumables, equipment etc.), tuition fees, and an annual, tax-free stipend of approximately £16,500 per year for UK/EU students.

Eligible candidates: UK nationals only due to industry sponsor requirements.

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 to learn more about our centre and see the full list of projects that we have on offer this year.

The studentship is subject to funding availability.

About XM2

XM2 is the doctoral training programme of our Centre for Metamaterial Research and Innovation at the University of Exeter. We provide scientific knowledge as well as transferable and technical skills training to all our students to prepare them for careers within and outside of academia.
In 2014, we started off as a £12 million Centre for Doctoral Training (CDT) in Metamaterials, funded by the Engineering and Physical Sciences Research Council (EPSRC/EP/L015331/1), the University of Exeter and industry.

The PhD students learn together in targeted courses, self-driven activity groups, and exposure to industry to gain scientific background knowledge beyond their areas of expertise, and to equip themselves with transferable professional skills such as creative thinking, project management, and leadership.
XM2 now consists of more than 60 active PhD students (Postgraduate Researchers, PGRs) from the UK, the EU and beyond, who are training in a stimulating, challenging yet supportive cohort-based environment. Since 2018, over 30 graduates went into employment in industry and as postdocs in Higher Education Institutions in and outside of the UK.

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. 

We are one of the very few universities to be both a member of the Russell Group and have a Gold award from the Teaching Excellence Framework (TEF), evidence of our established international reputation for excellence in both teaching and research. Our success is built on a strong partnership with our students and a clear focus on high performance.
Exeter is also ranked amongst the world’s top 200 universities in the QS and Times Higher Education rankings

How to apply

Application criteria

Eligible applicants: UK nationals only.

Applications are made to the Metamaterials programme for a PhD in Physics/Engineering. We invite candidates to specify their project(s) of interest at the time of application.

Please ensure to upload ALL items listed below through our application system. Incomplete applications cannot be processed.

  • Degree transcript(s) giving information about the qualification awarded, the modules taken during the study period, and the marks for each module taken.
  • An academic CV;
  • A cover letter outlining your research interests in general, the title of the project(s) you are applying for;
  • A Personal Statement consisting of two parts*:
    • Describe a) why you would like to study for a PhD, b) why you would like to focus on this particular topic, c) any relevant expertise and d) your future career ambitions;
    • Describe the qualities that you believe will make you a great researcher (in particular as part of a team).
  • The contact details of two academic referees.

* We foster creativity and utilisation of individual strengths. Applicants are encouraged to provide evidence to support their statements. This might include conventional written documents (e.g. examples of work), but we also encourage alternatives such as audio or video recordings, websites, programming etc. Please ensure to include accessible links to such files in an appropriately named document as part of the upload process.

Application procedure


Applications will normally be reviewed within two weeks of receipt.

Candidates will be short-listed against a set of agreed criteria to ensure quality while maintaining diversity. Failure to include all the elements listed above may result in rejection.

The essential criteria:

  •              Undergraduate degree in a relevant discipline;
  •              Vision and motivation (for research & professional development);
  •              Evidence of the ability to work collaboratively and to engage in a diverse community;
  •              Evidence of excellent written and oral skills in English.

The highest quality candidates will also be able to demonstrate one of more of the following:

  •             Specialist knowledge about one or more of the 8 research areas listed above;
  •             Training in research methodology (e.g. undergraduate research projects);
  •             Research outputs (e.g. papers) and/or other indicators of academic excellence (e.g. awards).


Shortlisted candidates will be invited to an entry interview to assess fit to the CDT concept. This will be held prior the academic interview with the supervisors and will normally be undertaken by a panel of 3 people, including a current postgraduate researcher or post-doc in Physics or Engineering.

Interviews are expected to start within two weeks upon application receipt. It is therefore advisable to apply as soon as possible.

Please email if you have any queries about this process.


Application deadline:25th January 2021
Number of awards:1
Value:Approximately £105,000, including research and travel budget, tuition fees and annual taxfree stipend (approx. £16,500 per year payable to UK or EU students only).
Duration of award:per year
Contact: Dr. Isaac Luxmoore (Admissions Tutor)