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EPSRC Centre for Doctoral Training in Metamaterials 2017/18

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About XM2 – Research and Training

What are Metamaterials? Metamaterials are fabricated microstructures having properties beyond those found in nature. They are emerging as an important new class of electromagnetic and acoustic materials with applications in many technology areas: energy harvesting, efficiency and storage, imaging, communications, electronic circuitry, sensing and the much-hyped ‘cloaking’.

The EPSRC Centre of Doctoral Training in Metamaterials (XM2) is based on the Streatham Campus at the University of Exeter in the Departments of Physics and Engineering. We have a well-established and strong track record of relevant research, spanning a unique mix of interests, from microwave metasurfaces to carbon nanotubes, from the fundamental theory of electromagnetism and quantum mechanics, to new understanding in acoustics, from graphene plasmonics to spintronics, magnonics and magnetic composites, and from terahertz photonics to biomimetics. XM2 opened its doors to new PhD researchers in September 2014, and since then has been training researchers in a challenging yet supportive cohort-based environment. One of our unique aspects is that our post-graduates undertake research from day 1 whilst taking relevant courses in metamaterial physics, materials engineering, device production and characterisation. At the same time we offer wider professional and personal skills programmes such as innovation, industrial awareness, project management and leadership, alongside an understanding of outreach and public engagement. Our ambition is that our PhD students graduate as highly skilled and talented researchers, with the potential to become future leaders in industry and academia.

THE COHORT APPROACH Unlike traditional “lone scholar” PhDs, our cohort-based programme demands that our researchers work and learn together. It sets a stage so that individuals can flourish and discover their own potential (and limitations). This provides a strong local network of knowledge and experiences, a strong foundation for the whole research team to draw upon to drive their projects and personal development forward. XM2 has more than 60 PhD students across 4 cohorts drawn from the UK, Europe and beyond.

Get in touch and stay informed: email: metamaterials@exeter.ac.uk phone: (+44) 0 1392 726568 website: www.exeter.ac.uk/metamaterials facebook: /CDTMetamaterials twitter: @XM2_CDT

How to become part of XM2 LOOKING FOR A PHD STUDENTSHIP? A list of all projects for 2018/19 is available at www.exeter.ac.uk/ metamaterials/apply from November each year. The studentships have a value of up to £95,000. UK and EU: annual tuition fees, stipend (£14,500 – £16,500 in 2017/18) and project costs (approx. £11,000 for travel and consumables). Non-EU: International tuition fees and project costs only.

INTERESTED IN BECOMING AN INDUSTRIAL OR ACADEMIC RESEARCH PARTNER? If you’d like to explore possible engagement opportunities with our Centre through e.g: ▪ research collaborations, ▪ direct funding of individual projects or the overall Centre’s aims, ▪ provision of scientific training and/or supervision, ▪ research and careers talks, ▪ research knowledge exchange and networking events, please contact our Programme Manager, Dr Anja Roeding, or Professor Alastair Hibbins via metamaterials@exeter.ac.uk.

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Foreword

The XM2 Team

ROY SAMBLES

The Director and Co-Directors are investigating a broad spectrum of research topics – from interaction of sound and light with matter, over quantum technology and biosensing to the design and development of future generation, non-volatile, memory technologies.

XM2 DIRECTOR

Professor of Experimental Physics at the University of Exeter

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ISAAC LUXMOORE

Professor of Experimental Physics; Director

Lecturer in Nanophotonics, Co-Director

BILL BARNES

DAVID WRIGHT

DR IAN HOOPER

Professor of Photonics;

Professor of Electronic Engineering, Co-Director

Technical Director

Our Centre for Doctoral Training in Metamaterials (CDT) has matured into a highly productive research and training collective. We have built on our existing research expertise, PhD supervision, and teaching practices to develop a vibrant, supportive yet challenging PhD training environment.

Our current PGRs demonstrate fantastic spirit and engagement, resilience and the drive to make a difference. They help to maintain a supportive, collegiate environment that allows incoming students to feel welcome and part of the growing Metamaterials research community at Exeter and beyond.

It is gratifying to see that all of the students are progressing well, with the majority having already published papers and presented at international conferences.

With the growth of our Centre comes a significant challenge in regards to its management. We welcome our new administrator Deborah Lee and Dr Anja Roeding as our Programme Manager. In addition, Dr Isaac Luxmoore has joined the Management Board to lead on the further development and implementation of our training.

Co-Director

We look forward to another challenging and eventful year as we work and learn together with over 60 PhD students, more than 30 supervisors and our academic and industry collaborators outside Exeter.

Professor of Metamaterial Physics, Co-Director

As the first cohort approaches their final year they are preparing for their theses submission and the subsequent move to successful careers in industry, academia, government or other institutions. They will leave Exeter with the ability to design and harness the functionality of Metamaterials, maintaining and furthering the UK’s position in this rapidly developing field, equipped with a strong skill set to meet future challenges on the career pathway of their choice.

THE ACADEMIC DIRECTORS ARE SUPPORTED BY

ROY SAMBLES

DR ANJA ROEDING Programme Manager

ROSIE DIXON Administrative Officer

ALASTAIR HIBBINS DEB LEE Administrator

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ROY SAMBLES

The XM2 Student Advisory Group

JONATHAN KINGHT XM2 OVERSIGHT BOARD CHAIR

Pro-Vice-Chancellor (Research) and Professor of Physics at the University of Bath The EPSRC Centre for Doctoral Training in Metamaterials trains researchers in areas spanning Physics and Engineering. Its ethos is one of excellence in research, of community, and of professional development. The Centre has worked hard to build momentum, by putting together a group of researchers at a variety of different career stages but of generally exceptional quality and with shared interests. It is a meeting-place for academics, postgraduate students, researchers and users of research, which is focused on developing a new generation of scientists able to work innovatively across boundaries. A key to the success is the high quality of the student intake: applicants are carefully screened and only the very best are accepted onto the programme. Another important factor is the strong sense of ownership by academics and students alike: a genuine enthusiasm for performing at the very highest level.

The Student Advisory Group (SAG) consists of members of each cohort who represent the student body at meetings with the Management and Oversight Boards. As the first cohort of students start to approach the end of their degrees, they are beginning to think forward to what lies beyond their doctorates. The Centre is fully engaged with helping them with this next step. Of course, the students of the Centre are well-placed for the next move, having been exposed to the highest standards of intellectual rigour and ethical consideration throughout their training. They have also benefitted hugely – and will continue to benefit – from the time, energy and effort shown by the external participants in the programme, whose advice on developing their prospects after their graduation is becoming ever more pertinent. And as new students are recruited onto the programme, they should be seeking opportunities to leave their own mark on the Centre, by identifying what particular contribution they can make.

JONATHAN KINGHT

CHRIS KING

BEN HOGAN

SAG chair, 4th Year

3rd Year

PABLO MARTINEZ PANCORBO 2nd year

ALBA PANIAGUA DIAZ 4th Year

HENRY FERNANDEZ PIZARRO 3rd Year

We became SAG members to help implement new ideas that benefit the overall experience of our peers, to offer different perspectives and to ensure the PGR’s opinions are heard.


Our Training Forewords

TRAINING We have designed our programme so that our students start undertaking research from day 1, yet we have also front-loaded much of the additional training programme to ensure that they can develop the skills they need at the earliest opportunity. One of the great strengths of doctoral cohort training is the additional benefits that we can provide our students over and above that available in a traditional PhD programme. In the first year our students undertake training in Creativity, Cognitive Behavioural Coaching (CBC), teaching, and project management, as well as taking courses targeted at the skills they will need to undertake their day-to-day research such as presentation skills, computational modelling and programming etc. As students progress into subsequent years their training will focus on Leadership, and the opportunity to undertake scientific outreach.

INITIAL 6-MONTH RESEARCH PROJECT

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A key aspect of our programme is to ensure that researchers, many of whom will have MPhys or MSc degrees or have engaged previously with research, are not engulfed with formal lectures but start their research work early. This means that the first year is exceptionally challenging as they balance the production of high quality research while also attending the additional training courses. Students are asked to produce research work of a quality that can be written up as a report in the form of a potentially publishable paper by the end of March. This is a major challenge, but our researchers have welcomed it and have produced some very impressive pieces of work, with several papers published by our first two cohorts directly resulting from their projects.

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A BROADER SCIENTIFIC EDUCATION In order to be successful as an academic, or within an industrial research environment, being an expert in your narrow field is often insufficient. It is essential that our students broaden their horizons both within the field of metamaterials, and without. To this end our students attend weekly seminars given by visiting academics on a wide-range of scientific topics, and we have developed a series of 2-day intensive workshops focused on the themes of Plasmonics, Magnetic Metamaterials and Devices, Acoustics, Fabrication and Characterisation of Functional Materials, Sensing and Security, Wave Theory, and Measurement and Control. These workshops are designed to be interactive and stimulating and, in order for our students to gain a perspective of research in an industrial environment, some of them are being run by experts from industry.


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The programme at a glance

CREATIVITY

SCIENTIFIC WRITING

We want to make an early start on many of the elements of training that our students are likely to be unfamiliar with, in order to help build new habits and better working practices. The center-piece of the Creativity workshop, provided by the The Silver Bullet Machine Manufacturing Company Ltd., is the theory that creativity is a process of forming different, and hopefully new, patterns from preexisting elements. This implies that, in a deep sense, nothing is new: all apparently new things are formed by bringing together pre-existing things. This is immediately evident in music - Beethoven didn’t invent any of the notes, but he did form some wonderful new patterns. Perhaps less obviously, it’s true in science too: so, for example, the X-ray diffraction pattern of a helix was known to be the characteristic X-shape (the “CCV” paper of 1952); Chargaff’s Laws had established that DNA is formed not of A-T-C-G tetramers but of A-T and G-C dimers (work published from 1949); and Rosalind Franklin’s PhD student, Raymond Gosling, took the critical X-ray picture in 1952, which was seen by Watson (1953). Watson, with Crick, put all these pieces together to describe DNA for the first time, but all of the pieces were there – anyone could have done it!

We have introduced the ‘Write about Science’ workshop provided by Mark Buchanan and Justin Mullins to give our researchers a competitive edge in the increasingly cut-throat worlds of publishing in science and engineering. With a balance of thought-provoking lectures, carefully chosen exercises and one-to-one feedback, the workshop focusses on the fundamentals of good communication and how to use them to produce scientific papers of the highest quality.

MONTH

Our Training

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COGNITIVE BEHAVIOURAL COACHING

STATISTICS

LEARNING AND TEACHING IN HIGHER EDUCATION

TECHNICAL TRAINING COURSES (PROGRAMMING, COMPUTATIONAL MODELLING ETC.)

WAVE THEORY

TAUGHT COURSE (STUDENT’S CHOICE)

FABRICATION AND CHARACTERISATION OF FUNCTIONAL MATERIALS

SCIENTIFIC WRITING

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MAGNETIC METAMATERIALS AND DEVICES

PROJECT MANAGEMENT FUNDAMENTALS OF ACOUSTICS PUBLIC SPEAKING PLASMONICS

LITERATURE REVIEW

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COGNITIVE BEHAVIOURAL COACHING

 

HEALTH AND SAFETY

PRESENTATION AND COMMUNICATION SKILLS

6 MONTH RESEARCH PROJECT

The aim of the Creativity workshop is to help students develop patterns of work that will enable them to solve their own problems and to come up with new ideas.

There is a growing evidence-base that postgraduate research progress can be enhanced through Cognitive Behavioural Coaching (CBC), and provision of this support has been designed into the XM2 programme. Staff in Exeter’s CEDAR (Clinical Education Development and Research) center offer CBC throughout each cohort’s studies aimed at strengthening academic adaptability and problem-solving commonly experienced obstacles to progression in both group and individual formats. The focus of these sessions can include topics such as goal-setting and self-monitoring, and enhancing skills to deal with issues such as procrastination and perfectionism or individual barriers to successful progression.

1ST CREATIVITY EVENT

SENSING AND SECURITY MEASUREMENT AND CONTROL

LEADERSHIP AND PROJECT MANAGEMENT Whilst during their PhD students will be focused on undertaking their research project, when they graduate they will quickly find that they are expected to take on management roles, leading research teams and managing projects. In order to develop these often-ignored skills, our students undertake courses in Project Management and Leadership. Both are run by an external training and consultancy company, Fistral Ltd., and have been incredibly well-received by our students. Our Project Management course takes place immediately after the student’s 6-month project so that they have some experience of undertaking research and are better able to put what they learn into the context of a research programme. The Leadership training takes place in the third year of the programme, and is designed to help students recognise different management styles and explore ideas in effective leadership.

TAUGHT COURSE (STUDENT’S CHOICE)

FULL PhD RESEARCH PROJECT

24 LEADERSHIP COURSE

IP AND BUSINESS AWARENESS

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Research Soft skills and employability

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ND

CREATIVITY EVENT

INTERVIEW TRAINING

Science Training I Science Training II (XM2 specific)

THESIS PREPARATION

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COMPLETE PhD (SUBMISSION, VIVA, CORRECTIONS)

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Our Training Throughout the year our PGRs attend monthly talks given by national and international academics and representatives from industry. ‘BEYOND A PHD’…

‘XM2 COLLOQUIUM’

…is a talk series that provides our researchers with the opportunity to learn from and network with successful Physics and Engineering graduates who pursued careers in industry, academia, and beyond.

In our Colloquium series the students gain insights into the latest developments in the wider science community, both in the UK and internationally. Examples of our guests in 2016/17:

How did they get were they are now? What obstacles did they face, how did their education prepare them for these endeavours, and what had did they have to learn on the job? Examples of our 2016/17

Prof Sir John Pendry, Theoretical Physics, Imperial College London, UK

presentation series:

Prof Niek van Hulst, Molecular Nanophotonics, The Insitute of Photonic Sciences (ICFO), Spain

Helen Thomas, Executive Producer, BBC Television, ‘So, what’s happening to Science TV and why should I care?’

Prof Richard Craster, Applied Mathematics, Imperial College London, UK

Prof Sir Bill Wakeham, ‘The employment and employability of STEM graduates; whose responsibility?’

Prof Nicolas Joly, Experimental Physics, Max-Planck-Institute Erlangen, Germany

Dr Peter De Maagt, ‘The European Space Agency’ Dr Steve Kitson, ‘Setting up your own business’

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OUR RESEARCH AREAS: •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


RESEARCH CASE STUDY

Our Research

ACOUSTIC AND FLUID-DYNAMICAL METAMATERIALS BENJAMIN ASH (4TH YEAR) MICROPHONONIC CRYSTALS

ACOUSTIC AND FLUID-DYNAMICAL METAMATERIALS ▪ Aero- and hydro-acoustic metasurfaces for manipulating the propagation of sound

▪ Fluid-structure interactions for influencing the flow of fluids

▪ 3D metamaterials and phononic crystals

▪ Microfluidic metamaterials for lab-on-a-chip technologies

▪ Coupling between acoustics and fluid-flow

SAM: I decided to apply for a project as part of XM2 as it seemed an excellent opportunity. I liked the sound of the mix between technical and non-technical training as well as the industry focus. Also the wide variety of projects available meant I could do something I was really interested in. The most memorable thing I have done so far is going to visit the CREATe group at Virginia Tech in the United States. I got to visit them for a week and helped them conduct an experiment while discussing the shared research interests of our two groups. Since then we have been working on a research proposal together.

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BENJAMIN ASH

JOSEPH BEADLE

4th year Microphononic Crystals

3rd year Exploration of acoustic waveguiding

THOMAS GRAHAM

VICKY KYRIMI

4th year Minimising acoustic reflections using structured surfaces

3rd year Exploration of negative group velocity acoustic surface modes

SAM SHELLEY

WILLIAM FERGUSON 2nd year

4th year Metamaterial concepts for the control of hydrodynamic flow

Our research area is the use of phononic crystals for surface acoustic waves at MHz frequencies. Surface acoustic waves are elastic waves that travel along the surface of a material and are widely used in electronic components for signal processing, sensing and increasingly for lab-on-a-chip applications. Phononic crystals can control the propagation of acoustic waves, enabling improved performance of existing device concepts as well as providing a route to more advanced applications. Recently we developed a new phononic crystal design consisting of periodic arrays of finite depth annular holes, as shown in figure 1. Through simulations and experiments we demonstrated that this phononic crystal can open bandgaps, which prohibit the propagation of surface acoustic waves at certain frequencies.

These bandgaps are induced by local resonances and can be tuned using the depth and radius of the holes. Importantly, this design improves upon the previously used pillar phononic crystal design by drastically enhancing the surface acoustic wave attenuation within the bandgap, even for relatively shallow features. A comparison of bandgap attenuation of our hole phononic crystal compared to conventional pillar phononic crystals is shown in figure 2. This work transforms the ability to exploit phononic crystals for developing novel SAW device concepts. Following this work, we are currently exploring the use of phononic crystals for acoustic superlensing. We aim to do this by fabricating negative index materials which can resolve images beyond the diffraction limit of conventional lenses.

ELIZABETH MARTIN 2nd year Microfluidic metamaterials for lab-ona-chip technology

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Starting in 2017/18: Jess Brown, David Tatnell

Figure 2. Simulated surface acoustic wave bandgap transmission for annular holes and pillars against number of elements in propagation direction.

Broadband Vibration Energy Harvesting for Low Frequencies

ELIZABETH: Being a PhD researcher provides you with the exciting prospect of constantly encountering new challenges to solve. Within my research I work on designing and creating magneto-elastic membranes using a generous variety of specialist equipment and facilities. Being a part of the Centre for Doctoral Training in Metamaterials provides you with a wide range of training opportunities that you can take advantage of to further your development in skills and academic topics outside of your everyday research. Furthermore, within our Center you have the benefit of belonging to a supportive student cohort, and the opportunity to interact with people from different research areas. This, in turn, can serve to aid your own research progression.

Figure 1. Fabricated annular hole phononic crystal. (a) Section of a square array of annular holes with depth 6.4 μm, inner radius 5.1 μm and pitch 10.9 μm. (b) Cross section depth profile of an individual annular hole with platinum within the hole to provide image contrast.

MY LATEST PUBLICATION

SUPERVISORS

Ken Evans, Alastair Hibbins, Simon Horsley, Geoff Nash, Feodor Ogrin, Peter Petrov, Roy Sambles, Chris Smith, Pete Vukusic, Meiling Zhu

 highly attenuating and frequency tailorable annular hole phononic crystal for surface acoustic waves, Nature Comms, 2017 (10.1038/ A s41467-017-00278-0)


RESEARCH CASE STUDY

Our Research

BIOLOGICAL AND BIO-INSPIRED METAMATERIALS

BIOLOGICAL AND BIO-INSPIRED METAMATERIALS ▪ Use of nanocellulose to provide biodegradable optical metamaterials

▪ Exploration of metastructures in wingscales and insect cuticles ▪ Biomimetics of natural photonic structures

▪ Magneto-elastic membranes

JOSHUA HAMILTON 3rd Year Magnetically actuated bio-inspired metamaterials

There is nothing more exciting than knowing that you are contributing to the discovery of something new. In the field of bio-physics, the research we conduct has the opportunity to be used in point-of-care devices, which could make a profound difference to people’s lives. I believe that the best part of XM2 is that it gives us the opportunity to learn about multiple research areas within both academic and industrial settings.

JOE MORGAN 3rd Year Lightweight, Transparent and Sustainable Metamaterials

As a PhD student working with graphene and cellulose based nanomaterials I feel that I am working at the forefront of materials science. Exeter University has a wide variety of state-of-the-art equipment along with post-doctoral researchers and academics with years of expertise and experience. This knowledge base has allowed me to experiment from both a materials science perspective (understanding the interfacial bonding between graphene and cellulose), and an engineering perspective (using the two materials for device manufacture). The device manufacturing is particularly useful for industrial applications and will prove crucial in applying for jobs after my PhD.

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JOSH HAMILTON (3RD YEAR) MAGNETICALLY ACTUATED BIO-INSPIRED METAMATERIALS In this work, we explore the experimental verification of a new class of autonomous ferromagnetic swimming devices, actuated and controlled solely by an oscillating magnetic field. The devices are comprised of a pair of interacting ferromagnetic particles (one NdFeB and one Fe) coupled together by a silicone rubber link (Figure 1).

Figure 1. (above) Fabrication of the device. (1) The particles are placed into a brass mould and aligned using an external magnetic field. (2) Liquid elastomer fills the mould (0.5 mm deep) and is left to cure. (3) The final device (Dimensions: overall length 3.6 mm). Figure 2. (right) Trajectories at different frequencies and field strength, the final point on each trajectory is at 2.31 seconds demonstrating the difference in speeds. The mean orientation of the swimmer is shown schematically for each frequency. Due to the difference in magnetics properties of the two particles, the application of an external magnetic field leads to time varying dipolar gradient force between the particles (resulting in a relative radial motion) as well as time-dependent torque (causing an oscillatory rotational motion of the whole system). The combination of these two interactions modulated by the elastic link binding the particles and the hydrodynamic coupling through the viscous fluid was shown to successfully propel the device through a fluid. We investigate the dynamic performance of a prototype (3.6 mm) of the ferromagnetic swimmer in fluids of different viscosity as a function of the external field parameters (frequency and amplitude) and demonstrate stable propulsion over a wide range of Reynolds

SUPERVISORS

Monica Craciun, Feodor Ogrin, Peter Petrov, Yanqiu Zhu

numbers. We show a robust control over the speed and direction of propulsion by manipulating the frequency and amplitude of the external magnetic field, these can be seen in Figure 2. Following this work, we are considering applications in which such devices can be used. An application of interest would be for lab-on-achip microfluidic systems. Such systems could involve the device being used as basic components for pumps and valves, to manipulate the flow of fluids in micro-scaled channels.

MY LATEST PUBLICATION  Magnetically controlled ferromagnetic swimmers, Scientific Reports, 2017 (10.1038/srep44142)

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Out and About THREE-DIMENSIONAL GRAPHENE FOAM FOR USE IN TISSUE ENGINEERING AND REGENERATIVE MEDICINE

‘BEST STUDENT TALK’ AWARD, MATERIALS RESEARCH SOCIETY SPRING MEETING IN PHOENIX (US) 2017 YULIA DAUTOVA 3rd Year

My most memorable experience in XM2 so far was my first conference, which took place in Italy. We didn’t have anyone to look after our child, so we went there with the whole family (and some careful planning!). I even took my son with me to some sessions. That’s what I call early development! Yulia presented at the MRS Spring Meeting in Phoenix, US (www.mrs.org/spring2017) and received the NKT Photonics ‘Best Student Talk’ award in her session.

COMPLEX NANOPHOTONICS SCIENCE CAMP, LONDON In July 2017 some of the current CDT students attended the Complex Nanophotonics Science Camp near London – and brought along our new student Justus Bohn, who will formally start in September 2017. The students used the opportunity to present their research to international experts in the field, and attended talks from successful researcher, such as Prof. Miles Padget, Prof. Monica Ritch-Marte or Prof. Juanjo Saenz. With around 150 participants it was the ideal occasion to network with a big variety of people. 60 second poster pitches provided a fun opportunity to exchange research project summaries – a great way to get a quick overview of lots of ongoing things. The event is highly recommended for people working in Complex Nanophotonics.

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TANVEER AHMAD TABISH 4th Year

In July 2017 I travelled to the Politecnico di Milano, Italy, to work for two months in the Biomaterials and Tissue Engineering research group, developing three dimensional graphene foam based biocompatible scaffolds that allow stem cells to regrow, differentiate, and proliferate in a 3D microenvironment, as well as to facilitate the development of novel regenerative medical treatments to help restore and strengthen lost functionality. Stem cell culture requires scaffolds to offer microenvironments for stem cell viability and the growth of 3D networks, promoting their biostability, survival, integration, enhanced differentiation, and synergistic cell control signals. 3D graphene foam is a promising candidate in the tissue engineering field; it has a number of superior physic-chemical features compared to conventional biomaterials, such as mechanical strength and corrosion resistance, while offering a complex structure for cell adhesion and cell network integration. I worked with Prof. Lorenza Draghi to investigate the potential of 3D graphene porous network as stem cell therapy agents, and to undertake experiments investigating the bioavailability of graphene in fibroblast, bone marrow, and nervous system cell lines. Preliminarily, it was found that graphene foam supports cell attachment, growth, and enhanced cell differentiation states. This study will further the development of advanced 3D graphene platforms for stem cell based therapies. The 3D architecture of graphene could be optimized for biomolecular selectivity and surface biostability, leading to unique interfacial properties not achieved through existing stem cell therapy based approaches. This visit was an amazing opportunity for me to undertake research in an exciting and active research environment, and allowed me to develop a range of new research skills.

CHARLIE-RAY MANN 3rd Year

Charlie won on the Rank Prize Award for the most outstanding short paper (shared with Paloma Arroyo Huidobro from Imperial College) for his quantum theory on “Unconventional Dirac Polaritons in Cavity-Embedded Honeycomb Metasurfaces” at the Rank Prize symposium on Electromagnetic Metasurfaces in March 2017. Among the guests were some distinguished speakers such as Professor Sir John Pendry and Professor Nader Engheta, who were part of the jury that judged the presentations on scientific/ technological content, presentation style, evidence of independent work, and novelty of ideas. The event provided a forum in which invited leading scientists and young researchers could meet and interact, in order to stimulate discussion and advance the development of their research field.

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RESEARCH CASE STUDY

Our Research

GRAPHENE AND OTHER 2D MATERIALS, AND RELATED DEVICES JAKE MEHEW (4TH YEAR) NOVEL OPTO-ELECTRONIC DEVICES BASED ON GRAPHENE PLASMONICS

GRAPHENE AND OTHER 2D MATERIALS, AND RELATED DEVICES

Atomically thin materials are enabling a new paradigm in ultrasensitive light detection by leveraging on a unique selection of properties, thus allowing an expansion in the range of potential applications. For instance, these materials offer the ultimate lightweight solution for the creation of space-bound photodetectors, or wearable optoelectronic devices.

▪ Flexible metastructured detectors and sources for infrared and THz ▪ Multifunctional ultra-lightweight energy harvesting coatings ▪ Metastructures for underwater acoustics

JAKE MEHEW

4th year Novel opto-electronic devices based on graphene plasmonics

CHENG SHI

3rd year 2D/Meta-materials Infrared Optoelectronic Devices

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KIERAN WALSH

2nd year Ultra-lightweight energy harvesting coatings based on two-dimensional materials

TOBY OCTON

4th year Plasmonic 2D metaldichalcogenide photodetectors for optical fibre communications applications

CRAIG TOLLERTON

3rd year Novel 2D materials for plasmonics and photonics

CHARLIE-RAY MANN

3rd year Plasmonic lattices from diffractive structures to 2D metamaterials

FRANCIS DAVIES

2nd year Engineering the thermal conductivity of few layer 2D materials

So far, the operational bandwidth of atomically thin heterostructure photodetectors is typically below 1 Hz, due to the presence of defects and disorder, which is too slow for many practical applications. Faster operational speeds have been demonstrated but these require the use of large gate voltage pulses, an extremely impractical strategy in highly integrated architectures. To circumvent this limitation, we have encapsulated heterostructure photodetectors of tungsten disulphide (WS2) and graphene in an ionic polymer, see Figure 1.

In such a structure, light is primarily absorbed in the WS2 generating electron-hole pairs with one charge carrier transferred to graphene whilst the other remains trapped within WS2. Owing to the ultra-high conductivity of graphene, a gain mechanism is possible whereby this charge carrier is recirculated multiple times before recombination with the trapped charge. Therefore, for a single photon the number of charge carriers extracted at the electrode can exceed 106 allowing ultra-sensitive light detection across a broad spectral range, Figure 2a. Unique to our work, we demonstrate that the efficient electrostatic screening of charged impurities and defects, by encapsulation of the device in an ionic polymer, results in photodetection response times more than 103 times faster than previously reported, without the need for large gate voltage pulses, Figure 2b. The combination of both high sensitivity to light and fast response times make these photodetectors suitable for video-frame-rate imaging applications and as a result the creation of atomically thin cameras can be envisioned.

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KIERAN: It’s exciting to be working in a field like 2D materials because it’s developing so quickly. My work revolves around exploiting the properties of 2D materials to harvest solar energy, and developing technologies (hopefully) that can be used in the not-too-distant future. XM2 provides the best possible environment for me to do this because I have a wealth of great researchers around me to bounce ideas off, as well as the independence to get stuck into experiments and really drive where I want my project to go.

Figure 1. 3D illustration of the WS2-graphene photodetector with electrical connections included.

Figure 2. (a) Responsivity, R, as a function of incident photon energy, E, revealing spectral range of WS2-graphene photodetector. (b) Normalised photocurrent signal, Ipc/Ipc0, as a function of light modulation frequency, f. Inset eye diagram acquired at 2.9 kbit/s.

SUPERVISORS

Bill Barnes, Monica Craciun, Euan Hendry, Steve Hepplestone, Isaac Luxmoore, Eros Mariani, Geoff Nash, Saverio Russo, David Wright

MY LATEST PUBLICATION

Fast and Highly Sensitive Ionic-Polymer-Gated WS2–Graphene Photodetectors, Advanced Materials, 2017 (10.1002/adma.201700222)


RESEARCH CASE STUDY

Our Research

MAGNONICS, SPINTRONICS AND MAGNETIC METAMATERIALS NATALIE WHITEHEAD (3RD YEAR) GRADED INDEX MAGNONICS

MAGNONICS, SPINTRONICS AND MAGNETIC METAMATERIALS ▪ Programmable magnonic metamaterials

▪ Artificial magnetic materials and their tuneability

▪ Spintronics

▪ Magnetic composites

▪ Spin wave based data and electromagnetic signal processing

CONOR: I intensely enjoy solving theoretical problems in physics, particularly when the project has clear

Our research involves developing the theory of waves in magnetic structures. In particular, we’re looking at ‘graded index’ structures – which have gradually changing magnetic properties – which gradually change the behaviour of waves which pass through them. This work is inspired by the well-developed research area of graded-index optics, which uses a changing refractive index to manipulate the behaviour of light. In our recent publication, we also looked at how a particular graded index structure can act as a source of waves.

observe. We’re hoping to research this in more detail in future, and also investigate other graded index profiles to generate and manipulate spin waves.

practical applications. Therefore, I am grateful for the strong emphasis placed on academic and industrial collaboration in XM2, and I am delighted that my research can have direct impact for the industrial sector.

ERICK BURGOS PARRA 4th year

Time resolved imaging of spin transfer oscillator arrays: towards active magnetic microwave metamaterials

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CAMERON GALLAGHER 4th year Domain structure and microwave characteristics of particulate magnetic composites

CONOR MCKEEVER 4th year Microscopic modelling of interacting magnetic particle assemblies in a dielectric medium at microwave frequencies

ANGUS LAURENSON 3rd year Quasi-classical formulation of magnonics

DAVID OSUNA-RUIZ 2nd year Magneto-actuated Morphing Metamaterials Figure 2. The oscillation of the magnetisation, showing the domain wall in the

CALLUM VINCENT

JACOB ROTH

3rd year Time-resolved imaging of surface acoustic and spin waves excited in 2D metamat

2nd year Propagation of magnetic flux through a nanostructured magnetic metamaterial

NATALIE WHITEHEAD

JONATHON VENTHAM 2nd year

3rd year Graded index magnonics

Magnonic metamaterials for smart applications

TIMOTHY SPICER

KEVIN FRIPP

4th year Excitation of picosecond magnetisation dynamics by spin transfer torque

3rd year High-speed spin-wave devices

Starting in 2017/18: Emily Glover, Peter Inzani

ERICK: During my studies, I have had the opportunity to work in some of the most important synchrotrons in Europe, and to collaborate with other prestigious research groups. This could not have happened without XM2, which provides us with the training and support we need to achieve our goals, including a generous budget for research related activities. I am passionate about research and confident that I will be able to apply all that I have learnt as I continue my path towards building my own research group one day.

SUPERVISORS Mustafa Aziz, Jacopo Bertolotti, Alastair Hibbins, Robert Hicken, Simon Horsley, Gino Hrkac, Volodymyr Kruglyak, Feodor Ogrin, Tom Philbin, Roy Sambles, Andrej Shytov

centre of each image and the ripples of the spin waves which move away from it. Main image shows the position of the magnetisation at phase = 0, and the inset is for the phase = π.

Figure 1. The ‘Bloch’ domain wall that we studied, where the magnetisation (indicated by the blue arrows) rotates out of the plane between two antiparallel domains.

In a magnetic material, there are regions (called ‘domains’) where the magnetisation is aligned in the same direction – and so adjacent domains might have the magnetisation pointing in completely opposite directions. Between these domains exists a domain wall, where the magnetisation gradually rotates from one orientation to the other – see Figure 1. These domains are tiny (about 10 times the spacing between atoms) and in recent experiments they have been found to generate waves of energy in the material, called ‘spin waves’, although the mechanism for this is unclear. We have developed a theory which explains this mechanism. We find that, even when you apply a small magnetic field across a domain wall, which is uniform everywhere but oscillates in time, you can generate spin waves (see Figure 2). Importantly, we find that it isn’t the motion of the domain wall which generates spin waves (as many papers presume) – it is created simply because of the presence of the domain wall’s graded index, along with the uniform external field. If you move the domain wall around and then the domain wall generates spin waves, that would be a nonlinear effect – which is not what we (or many other papers)

MY LATEST PUBLICATION  Theory of linear spin wave emission from a Bloch domain wall, Physical Review B, 2017 (10.1103/PhysRevB.96.064415)

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RESEARCH CASE STUDY

Our Research

MICROWAVE METAMATERIALS LAUREN BARR (4TH YEAR) DIRECT OBSERVATION OF TOPOLOGICALLY PROTECTED MODES IN A MICROWAVE METAMATERIAL

MICROWAVE METAMATERIALS ▪ Metasurfaces and surface waves

▪ Resonators and energy harvesting structures

▪ 3D metamaterials and photonic crystals

▪ Filtering, absorbing and channelling microwave energy

▪ Compact and functional antennas

▪ Active metamaterials

YULIA: After graduating from university I worked in software development, but was always inspired by science, which, for various reasons, wasn’t an option at that time. I had been working in software development for 8 years and really enjoyed it, but I then became aware of the Centre for Doctoral Training in Metamaterials in Exeter and decided that I couldn’t miss such an opportunity to bring my dream to life. I am always keen to have changes and new challenges in my life, and a PhD was the right type of challenge to try. Moreover it will improve my CV and open up new opportunities in my future career.

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LAUREN BARR 4th year Direct Observation of Topologically Protected Modes in a Microwave Metamaterial

YULIA DAUTOVA 3rd year

SATHYA SAI SEETHARAMAN 4th year

MILO BARACLOUGH 2nd year

Hyperbolic meta-materials and the emission of EM radiation

Microwave metamaterials as models of molecular light harvesting systems

MIGUEL CAMACHO AGUILAR 3rd year Thin metal multilayers for microwave applications

I have good news! I’ve been selected for the IEEE Award. (Miguel, 3 Aug 2017)

JULIA DE PINEDA GUTIERREZ 2nd year Exploration of beam shaping at microwave frequencies using metasurfaces and metamaterials

Starting in 2017/18: Pavel Petrov

The metamaterial has a tri-layer unit cell, shown in fig. A. The top layer is a copper helix embedded in a piece of circuit board. This is chiral, and so breaks the inversion symmetry in the metamaterial. The next layer is a long copper wire on a circuit board, which makes the metamaterial hyperbolic (the dispersion curves extend to infinity, rather than forming a closed loop). The crosses on these wires are there simply to adjust the capacitance between neighbouring wires. The bottom layer is plain circuit board to prevent electric connection between layers. This unit cell is repeated in three dimensions to make a bulk material. As the metamaterial is chiral and hyperbolic, the dispersion curve shows Weyl points. These are the 3D version of Dirac points, as seen in the dispersion of graphene. These Weyl points are always present in pairs of opposite chirality, and lead to the presence of surface modes that have different topological charges. A wave that exists on one surface mode cannot jump into the other, and so cannot travel in the opposite direction. If we look at the dispersion plot in fig. B we see solid white lines that represent the modes in the bulk material, and dotted blue lines that represent the topologically protected surface modes. The experimental data was collected in Exeter using a near-field scanning technique, and analysed to show the experimental dispersion. We were also able to directly image a wave travelling over a sharp corner in the experiment, shown in fig. C, proving that the wave is indeed topologically protected. This was the first time that these surface modes had been directly imaged in an experiment, and it was a very exciting project to be involved in.

Figure A. Schematic of the unit cell of the 3-dimensional metamaterial showing the helix (chiral) and wire (hyperbolic) components. Figure B. Dispersion diagram with simulated bulk (solid white) and topologically protected surface (blue dotted) modes, and experimental results (colour plot). Figure C. Experimental measurement of a surface wave travelling over a sharp step in the material without scattering backwards.

In August 2017, IEEE awarded Miguel an Antennas and Propagation Society Doctoral Research Grant in the amount of US$2,500. The selection committee commends on the high-quality proposal Miguel prepared, and hopes that the grant funds will enable him to continue his electromagnetics education.

SUPERVISORS

Scattering and Localisation of Microwave Surface Waves

This year I worked on a project with our collaborators in Birmingham on a very interesting kind of metamaterial. We created a material that supports an electromagnetic wave that can travel in only one direction – the wave is topologically protected. This is useful for communication networks, as when a wave of this kind travels around a corner, or over a defect, it won’t be scattered backwards, so there is no loss of signal. Instead of working at the infra-red wavelengths used in communications, we worked at GHz frequencies, where the wavelength is slightly longer (around 3 mm) and the materials easier to build.

Bill Barnes, Euan Hendry, Alastair Hibbins, Ian Hooper, Roy Sambles

MY LATEST PUBLICATION  Direct observation of topological surface-state arcs in photonic metamaterials, Nature Comms, 2017 (10.1038/s41467-017-00134-1)

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Out and About

Our Social Media Team

FRAUNHOFER CENTRE FOR APPLIED PHOTONICS IN GLASGOW

XM2 students are leading on the social media presence of XM2 and EUOPS.

ALBA PANIAGUA DIAZ 4th Year

In April 2017 I visited for three weeks the Fraunhofer Center of Applied Photonics in Glasgow to get a better idea of what working in industry is like. My research project is not directly associated with industry at the moment, and I was grateful for the opportunity to choose another short term project in optics offered by David Stothart, leader of the research group I worked in at Fraunhofer. I decided to go for the one involving the building up of a ring cavity laser. It really was a great experience; I learned a lot about lasers and their technicalities, I was even able to build a nice working one and only then realised how challenging that is! I met new people who made me feel very welcome and like a member of the group. I liked that the work is more customer oriented than in academia, quite a different motivation to go about projects! In short, I found this experience very useful to learn new skills and gain understanding of different pathways for the time after completing my PhD. I would definitely recommend such a research visit to everybody!

Sam Shelley and Jake Mehew are investing time and effort into the XM2 Facebook and Twitter pages to communicate the XM2 activities to the world. Tom Graham is our newly designated XM2 photographer to capture our events, and Henry Fernandez has taken on the role as designer and social media administrator of EUOPS.

SAM SHELLEY 4th Year

I decided to help with the CDT Facebook and Twitter accounts because it seemed a good way to keep everyone up to date with what was going on within the CDT. It has been fun to do as I get to see what everyone has been up to and to talk to them about it. The only challenges have been remembering to post on a regular basis and making sure everyone takes high quality pictures when they do something interesting.

JAKE MEHEW 4th Year

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EXPLORING BROADBAND METASURFACES AND ANTENNA DESIGN IN SWEDEN AND SPAIN MIGUEL CAMACHO AGUILAR 3rd Year

In the past year I have had the opportunity to visit two research groups in KTH Royal Institute of Technology (Stockholm, Sweden) and University of Seville (Spain), with who I work very closely. First I spent February in Stockholm working with Prof. Quevedo-Teruel, who is a leader expert in the development of broadband metasurfaces that make use of a special class of symmetries. We developed a method to extend the broadband behaviour to systems that don’t have such special symmetries with special application to coplanar waveguide technology (which strictly forbids any special symmetry between the two lines). This work has led to the submission of two journal articles currently in review. The possibility of visiting another research group which is more engineering-oriented has helped me broaden my vision of metamaterials and to be confident to apply my knowledge to Miguel and Prof. Quevedo-Teruel at a conference in San Diego the design of antennas. Later, in June I spent four weeks visiting my collaborators at the Microwave Group in Seville, where we worked on extending our highly efficient analysis tool for the design of slot arrays to include the presence of multi-layered dielectrics. We finished a piece of work that has been now submitted to Optics Express and we are preparing the submission of two more journal articles. This design tool has already brought the attention from transmitarray antenna practitioners which may lead to new future collaborations. I consider the chance of visiting other research group to be crucial for the development of my career. Although sometimes stressful due to the time constraints, they have meant a huge impulse in my outputs and experience and I have no doubt they will be essential for my future in academia and my relationship with industry. I am very lucky to have the support of the CDT and my supervisors to spend so much time learning from others to then contribute to my research group and my cohort.

The success of scientific research is not solely measured by the end result. Rather, how results are disseminated is becoming ever more important. With this in mind myself and a few others have been publicising, on various social media platforms, work undertaken by CDT researchers. This includes the latest results and publications, outreach activities, and visits to conferences or research institutes. Often, the most challenging aspect of this is breaking down the scientific terminology to a level that is both accessible and interesting to a general audience.

TOM GRAHAM 4th Year

I volunteered to become the CDT photographer as I’ve always had an interest in photography, so I know my way around a camera. My interest in photography comes from the fact that I have family working in film and I’ve been handed down cameras and other equipment over the years. Taking on this role is a good opportunity to combine a hobby and my interest in science.

HENRY FERNANDEZ PIZARRO 4th Year

My job as social media administrator for EUOPS is to spread the information of society activities to the community and to provide an easy way of communication. I’m currently working on the design of our advertisement as well, which includes banners and posters to be presented in important conferences, where more societies of the field of optics and photonics, form different countries, will be attending.

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RESEARCH CASE STUDY

Our Research

OPTICAL, INFRA-RED AND THZ PHOTONICS AND PLASMONICS BEN HOGAN (3RD YEAR) 2D LIQUID COMPOSITES FOR INTEGRATED OPTOELECTRONIC DEVICES ON SI

OPTICAL, INFRA-RED AND THZ PHOTONICS AND PLASMONICS ▪ Light at the nanoscale

▪ Phase-change photonic devices

▪ Nanoplasmonics for metamaterial applications

▪ Optically tuneable metamaterials

▪ Graphene based devices

▪ Subwavelength imaging

The liquid crystal phase has been known and studied for over 100 years (Figure 1) with a wide range of modern-day applications- most notably being ubiquitous in displays. But where else could they find applications? My current research work is focussed on the development of novel liquid crystalline composites incorporating two-dimensional materials (graphene etc.) for applications in optoelectronics and photonics.

CARLOTA: What excites me about my project is the idea of combining phase-change materials with metamaterials fascinated me from the beginning, as it can potentially result in novel photonic devices for  amplitude and phase control of optical waves in small timescales (nanoseconds)

SANTIAGO GARCIACUEVAS CARRILLO

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4th year Phase-change metamaterials for optoelectronic device application

JOAQUIN FANECA RUEDAS 2nd year Photonic Metamaterials for WDM optical communication applications

EMANUELE GEMO

ALBA PANIAGUA DIAZ 4th year

KISHAN MENGHRAJANI

Imaging in turbid and opaque media

3rd year Excitonics: an organic route to Metamaterials

THOMAS COLLIER

CARLOTA RUIZ DE GALARRETA FANJUL 3rd year

ROSAMUND HERAPETH 2nd year

LIAM TRIMBY

HARRY PENKETH

3rd year Chalcogenide perfect absorbers for the detection and modulation of infra-red radiation

2nd year Metamaterials for lighting

3rd year Carbon nanotube arrays for THz generation: Theory and applications

Electronically controllable optical wavefront shaping with phase change materials

HENRY FERNANDEZ

BEN HOGAN 3rd year 2D liquid composites for integrated optoelectronic devices on Si

3rd year Using nanostructure to create hybrid light-matter states: a combined electrical and optical investigation

HARRY: I applied for a PhD as, towards the end of my degree, I became passionate about my Master’s research project. I was drawn to XM because of its cohort-based approach and the training it provides in preparation for a career that may be outside of academia. I firmly believe in the benefits of having many colleagues with which to discuss your research. I particularly enjoy having the opportunity to regularly interact with senior academic staff and always find this insightful. 2

2nd year Plasmonic integrated allphotonic memories

THz imaging using dynamic metamaterials

Figure 1. Timeline of the history of liquid crystal phase applications, from their discovery to the present day. By utilising the reconfigurability of the orientation of the liquid crystal mesogens under applied fields (electric, magnetic, thermal…) we propose that ‘metastructuring’ can be achieved. That is, twodimensional nanoparticles dispersed within a liquid crystalline host can be controllably positioned to form metamaterial structures (Figure 2). We have shown that liquid crystalline composites with dispersed two-dimensional material nanoparticles can be readily synthesised

and integrated into CMOS-compatible microfluidic systems [Hogan et al., Dynamic in-situ sensing of fluid-dispersed 2D materials integrated on microfluidic Si chip, Scientific Reports, 2017]. As part of this work, we developed a novel characterisation method, using Raman spectroscopy to elucidate the positions of nanoparticles within microfluidic structures. In the (near) future, this novel methodology will allow us to monitor the spatio-temporal evolution of metastructure formation under applied fields.

Figure 2. A CMOS photonic XM2 6 month projec t presentation pr ize winner 2017!

SUPERVISORS

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Anna Baldycheva, Bill Barnes, Jacopo Bertolotti, Harish Bhaskaran, Monica Craciun, Euan Hendry, Geoff Nash, Misha Portnoi, Saverio Russo, David Wright

circuit coupled to a microfluidic layer integrating dynamically reconfigurable 2D material metastructures, with in-situ micro-spectroscopy detection and monitoring.

MY LATEST PUBLICATION  2D Material Liquid Crystals for Optoelectronics and Photonics, Journal of Materials Chemistry C, 2017 (10.1039/C7TC02549A)


Our Research NANOMATERIALS AND NANOCOMPOSITES

QUANTUM METAMATERIALS

▪ ▪Nanometamaterials, nanorods, nanowires, nano-tubes of carbon or carbon based structures

▪ Exploitation of coherent quantum dynamics to control electromagnetic waves

▪ ▪Carbon nanotubes and graphene for energy conversion and storage

▪ Magnetic field sensing with quantum metamaterials

▪ ▪Composites for control of electromagnetic radiation

ILYA STARSHINOV

PABLO: I applied for the XM2 studentship because I wanted to become an expert in physics and materials

4th Year Spontaneous generation of quantum correlations in natural media

engineering while being part of a cohort-based program. The combination of physicists, engineers and chemists collaborating together is far more productive than when they work alone. In the future I want to improve my technical skills to become a lead scientist either in industry or academia.

LAICONG DENG 4th year Nanoporous Graphene Materials for Electrochemical Energy Storage and Conversion Application

I chose to join XM2 because it is an avenue to conduct world recognized research within an outstanding team of academic researchers and peers. I get from my project everything that a PhD student could wish for: academic and non-academic support, training, effective supervision, and interesting problems to tackle.

ZAHID HUSSAIN 2nd year “Black” ZnO and TiO2 nanostructures for high efficient visible light photocatalysis

My project allows me to explore the limits of what is possible, and the ways we can reach them. Its aim is to answer how much information can be retrieved from an image of an object, and how quantum mechanics may help to improve this.

NED TAYLOR

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TANVEER AHMAD TABISH 4th year

PABLO MARTINEZ PANCORBO 2nd year

2nd Year Understanding the mechanism of colossal permittivity materials

Fabrication and Luminescence of Graphene-Like Carbide Quantum Dots

Functional, specially-doped Core-shell nanoparticles for biomedical imaging applications

A PhD gives you the chance to solve new problems on a daily basis. I constantly learn how to use new tools and new techniques in order to tackle various different and challenging problems that present themselves. Within XM2, I get to throw ideas back and forth with other students in order to help further my research.

Starting in 2017/18: Shane Davies

MY 6 MONTHS PROJECT IN A NUTSHELL:

ZAHID: My research project is about the synthesis of affordable and non-toxic nanomaterials for potential applications in cleaning industrial waste water, in hydrogen generation for fuel, and in solar cells. XM2 provides me with the opportunities and learning environment to equip myself with the skills I will need to contribute to the future of science and technology.

Using quantum mechanics, we can obtain the fundamental properties of a material by modelling its electronic charge density as a set of wave functions. Through use of density functional theory, we can obtain all of the electronic properties attributed directly to a perfect crystal. By also modelling imperfections within systems, we are able to determine which properties of a system are due to the perfect crystal and which are due to defects and interfaces. To be able to understand many of the characteristics of a material solely by understanding its electron distribution is quite an amazing prospect. In figure 1, we see an example of a charge density of the Fig 1: The unit cell of CaCu3Ti4O12, where the transparent yellow surface denotes the electron charge density. unit cell of CaCu3Ti4O12. As with all materials, we find here that the electrons Figure 1. The unit cell of CaCu3Ti4O12, aren’t localised to individual atoms, they are much more evenly distributed where the transparent yellow surface across a system. denotes the electron charge density.

SUPERVISORS

Nick Stone, Yongde Xia, Shaowei Zhang, Yanqiu Zhu

XM 2 6 month pr oject presentatio n prize winner 2017 !

SUPERVISORS

Janet Anders, Jacopo Bertolotti, Steve Hepplestone, Eros Mariani

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Our Research

Bristol

London

2.5 hours by train from Exeter

WAVE THEORY AND SPATIAL TRANSFORMATIONS ▪ Application of spatial transformation theory to electromagnetic and acoustic problems

▪ Theory of metasurfaces ▪ Theory of light propagation in complex media

Newquay

CHRISTOPHER KING 4th Year Using complex coordinates in optics

As far as I’m aware, I’m unique in entering XM2 with a single honours mathematics degree. This has led to some distinct challenges – there have been gaps in my knowledge that I’ve had to fill alongside undertaking my PhD research, but it has been rewarding to be able to broaden the knowledge-base of the Center, and understand the different motivations which make physicists and engineers tick. My PhD project has enabled me to apply my mathematical skills to physical systems that interest experimentalists.

DESIGNING REFLECTIONLESS MEDIA

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In general, electromagnetic waves are partially reflected at the boundary between two materials of different permittivities (the permittivity of a material measures how light inter-acts with the electric charges in the material). Our research is concerned with theoretically designing inhomogeneous media with suppressed reflection. Such materials may be useful as anti-reflection coatings for lenses, such as can be found on glasses, and may also be useful in the development of cloaking, where an object can be hidden by bending the path of light around it. We consider media whose permittivity varies smoothly in space, and it is the nature of this variation determines the relative amount of reflection, transmission and absorption. It is possible to construct such graded-index media using metamaterials. We have derived a family of one dimensional permittivity profiles ε(x), which don’t reflect waves incident from one side for any angle of incidence [1]. We have also obtained a subset of such media which, in addition to being reflectionless, also give perfect transmission (thus no absorption) [2], and subset that, in addition to being reflectionless, also gives perfect absorption (thus no transmission) [3].

Figure 1. A light wave is incident on a material with permittivity (x), which varies with the spatial coordinate x. In general, the wave will be partially reflected from, partially transmitted through, and partially absorbed by the material.

Figure 2. A light source is placed to the left (i) and right (ii) of an object satisfying the spatial KramersKronig relations and the electric field is plotted. The lack of ripples in (i) indicates that none of the light incident gets reflected for all angles of incidence whereas the ripples in (ii) indicate that there is reflection from the object. This is an example of a one-way reflectionless material.

Figure 3. A light source is placed to the left (i) and right (ii) of the medium and the electric field amplitude is plotted. As before, we observe the one-way reflectionlessness property. However, now the absence of the field on the opposite side of the material to the point source indicates that there is also zero transmission, and hence one-way perfect absorption.

MY LATEST PUBLICATION  Zero reflection and transmission in graded index media, Journal of Optics, 2017 (10.1088/2040-8986/aa7783)

SUPERVISORS

Simon Horsley, Tom Philbin

Truro Falmouth

Our Streatham Campus is easily accessible from London by train and European flights are available from Exeter, Newquay and Bristol airports.

Exeter is very easy to fall in love with. It has one of the most beautiful campuses in the country, in one of the most beautiful counties in Britain. Virgin Alternative Guide to British Universities

Following this work we are considering how to extend these ideas about designing reflectionless media to two dimensions. Specifically, we have considered periodic gratings which don’t diffract and nonreflecting beamshifters. [1] S. A. R. Horsley, C. G. King and T. G. Philbin, J. Opt. 18, 044016, (2016). [2] C. G. King, S. A. R. Horsley and T. G. Philbin, Phys. Rev. Let. 118, 163201, (2017). [3] C. G. King, S. A. R. Horsley and T. G. Philbin, J. Opt. 19, 085603, (2017).

Exeter

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Outreach METABUDDIES

THE BRILLIANT CLUB

Our PGRs piloted the ‘Metabuddies’ outreach scheme with Honiton Community College, where they visited year Year 9 – Year 12 students to discuss daily life as a researcher, to give a seminar on metamaterials, and to set research challenges that lead to poster presentations during a visit at the University of Exeter where the XM2 Director awarded a prize for the best poster.

Liam Trimby successfully passed an interview and a 2 day training course to volunteer for the award winning charity‚ The Brilliant Club, which aims to increase the number of pupils from under-represented backgrounds progressing to highly-selective universities by mobilising the PhD community to share its academic expertise with state schools.

SATHYA SEETHARAMAN 4th Year

I decided to take part in the Metabuddies programme for two reasons: 1) It is fun talking to school students about my work and everyday life as a researcher. I always end up learning something from them as they learn something from me. 2) It’s a good exercise trying to pitch my work at a level adjusted to the target audience. This practice will benefit me as a researcher who wants to pursue a career in academia and teaching.

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As the lead “buddy”, I collaborated with my team members to come up with an interactive and fun outreach programme for the students. This was the first time I’ve had to design a time-restricted mini-project for a group of students.

MY MOTIVATION: Teaching undergraduate classes has been one of the most enjoyable aspects of my PhD. When I came across the Brilliant Club I was curious, and then became very interested once I learnt I could design my own syllabus full of experiments. I was also in exactly the same position as these students when I was their age, and I really like the idea of widening participation in university education for students from under-represented backgrounds.

As a mentor I learnt when to step back to let the students drive the project and when to step in to guide them.

LAUREN BARR 4th Year

The highlight for me was working with the year 12 students on their challenges, as the ideas they came up with surprised even me. The tour of our research facilities on the day of the poster session was also a lot of fun, and the students got the chance to see what happens within the research groups in the physics department. The most difficult part was trying to explain what everyday life is like as a researcher in a University, as each day is so different!

FRANCIS DAVIES 2nd Year

I very much enjoyed visiting, teaching and talking to students, in particular researching and answering the questions given to us by the students. It was very difficult to balance my six-month project report, preparation for a conference presentation, and the Metabuddies scheme all at the same time, but it gave me the opportunity to investigate new thoughts and ideas stimulated by even the simplest of questions that required me to look up papers that I may have never read otherwise.

LIAM TRIMBY 3rd Year

I created my own highly applied 6-week course in electromagnetics pitched at A-level difficulty, and was assigned to a group of 12 year 10 students in Yeovil whom I taught for 2 hours every week for 6 weeks. This involved teaching theory and conducting experiments to see how well theory matched reality. The students built: lemon batteries, electromagnets, DC motors, a mag-lev train, an AC generator, and a basic railgun. It was my responsibility to give feedback and to set weekly homeworks, as well as a major 2,000 word assignment similar in style to a piece of undergraduate coursework, which I subsequently marked. One of the assignments was genuinely excellent, and would probably pass even at undergrad level! All of my students graduated from my short course with a ceremony at Bristol University. I think the most enjoyable part was conducting the practical experiments because the students were so engaged and excited with what they were doing. What I have learned… ?

… how challenging it is to know exactly how much a student has understood, and what they are still uncertain over! I think my ability to determine someone’s understanding is what improved most.

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Outreach TRANSLATING SCIENCE Zahid Hussain, 2nd year: I find it very important to explain new developments that are taking place in our disciplines to the general public and to make science more understandable for everyone. I am currently translating the book “Seven Brief Lessons on Physics”, written by Carlo Rovelli, into Urdu as I felt that there are lots of resources available in English, but fewer in other languages. I hope that this translated work will help Urdu readers to understand the new questions and philosophical challenges which scientists are confronted with at the moment.

COACHBRIGHT Maths treasure Hunt

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Joshua Hamilton, 3rd year: Part of the CoachBright program was a Maths Treasure Hunt with St Luke’s School. The aim was to get Year 9 pupils to get excited about maths, by solving short mathematical problems to find the treasure. Not only was the treasure hunt designed to be fun, it was also meant to help with solving mathematics tasks using new and fast methods.

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WINNERS OF THE OPTICS OUTREACH GAMES AWARD AT THE SPIE OPTICS AND PHOTONICS CONFERENCE 2017, SAN DIEGO, USA Erick and Jake won the Optics Outreach Games award at the SPIE Optics and Photonics conference 2017 held in San Diego, USA, the largest multidisciplinary optical science meeting in North America. Along with an incredible amount of technical talks (about 3300!) there is an entire programme aimed at professional development, networking with academia and industry, and improving leadership, presentation, outreach, and research skills. Our PGRs prepared an outreach activity on “A homemade spectrometer using a CD or DVD”, aiming to create something that could be built and used by anyone at almost no cost, and using only recyclable materials. They came top out of 19 competitors!

CDT students Jake Mehew (left) and Erick Burgos (right) with SPIE president Dr Glenn D. Boreman awarding the Optics Outreach games trophy.

WOMAD is a highly diverse, family-friendly festival which occurs annually in several countries worldwide. As part of the huge variety of events, the Institute of Physics hosted talks and practical experiments aimed at a younger audience throughout the day. The XM2 PGRs Erick, Liam, Pablo and Santiago spent a weekend to engage the festival guests with practical experiments on Galaxy Sun catchers, sunsets in a tube, particle collision mobiles, and ‘Marvin and Milo’ experiments. Their resume: it was a great experience with fantastic people and amazing workshops. They shared their knowledge and passion for science, and learned something new themselves: Erick and Liam were lucky enough to get hands-on musical experience with one of the world’s finest Theremin players!


Recruitment of Postgraduate Researchers XM2 projects for entry in September 2018 will be advertised from November 2017. All projects and full instructions how to apply are available at www.exeter.ac.uk/metamaterials/apply.

▪ an academic CV,

As part of the application process you will be required to provide:

Please note, failure to provide any of the above information may result in your application being rejected without consideration.

▪ an outline of your research interests, ▪ asuggestion of your preferred areas of study, and/or your interest in a particular project, ▪ an indication of whether you have already been in contact with a potential supervisor, ▪ a discussion of why you would like to study for a PhD in Physics or

▪ relevant degree transcripts including a breakdown of module marks, ▪ the names of two academic references.

Candidates will be short-listed by the Admissions Tutor against a set of agreed criteria (see our website). Short-listed candidates will be interviewed by a panel of two members of the Management Board. If successful a second interview will be undertaken by the potential academic supervisors.

Engineering, and why you would like to join a cohort-based doctoral training centre, Note that applications will be processed as soon as they are received. Interviews will be held from November and offers will be made from December. You are therefore advised to apply as soon as possible. APPLICATION DEADLINE:

See note above. International applications cannot be considered after 1 May

ELIGIBILITY:

Upper second or first class degree, or equivalent, in a relevant discipline.

VALUE:

Up to £95,000 UK and EU: annual tuition fees, stipend (£14,500 - £16,500 in 2017/18) and project costs (approx. £11,000 travel and consumables) Non-EU: International tuition fees and project costs only

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DURATION OF AWARD:

4 years. Entry in September only.

LOCATION:

Streatham Campus, Exeter (Physics or Harrison buildings)

HOW TO APPLY:

www.exeter.ac.uk/metamaterials/apply

ADMISSIONS TUTOR:

Professor Alastair Hibbins email: metamaterials@exeter.ac.uk phone: +44(0) 1392 726568

WHY APPLY FOR A CDT STUDENTSHIP? TOM GRAHAM 4th Year

To me, sharing is what XM2 is about. The opportunity to share work, worries and fun has been an incredible experience, and I’ll treasure my time with this group of exceptional people. When looking for a PhD place, I applied to a few universities, and a couple other doctoral training centres. After applying to Exeter I was sent the list of research topics. So many of the research topics overlap and work off each other, meaning that I was given a choice. This freedom of choice and the variety of research opportunities was too good to miss. No other university I applied to compared to the level of research and organisation that I experienced during the application process.

NED TAYLOR 2nd year

The cohort arrangement of XM2 allows students from multiple fields to engage and collaborate on research. We are given further training and teaching in areas outside of our specific PhD subject, helping us to understand where our research is grounded within the wider field of Physics. After my PhD, I hope to continue a career in academia. Regardless of whether you want to take your career into academia or industry, the extra skills you’ll learn from studying in a doctoral training centre will be invaluable in setting yourself apart from other students. With the additional courses supplied, such as in project management and leadership, we can demonstrate experience beyond that of a typical PhD student.

NATALIE WHITEHEAD 3rd Year

I get lots of inspiration from my colleagues! Being surrounded by people doing interesting research in other areas of physics is very motivating, and on top of this you have a supportive environment to work in - for me, this is much more preferable to doing a lone PhD.

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Special Thanks to… • OUR SUPERVISORS

• OUR OVERSIGHT BOARD

Strategic oversight of all aspects of the programme is provided by an Oversight Board (OB) which meets twice per year to offer independent evaluation of our activities and provide advice on appropriate research priorities and strategic directions, as well as on training, employability, knowledge-transfer, exploitation and dissemination opportunities.

ACADEMIC REPRESENTATIVES PROF JONATHAN KNIGHT Oversight Board Chair University of Bath, Professor of Physics and Pro-Vice Chancellor for Research

PROF MILES PADGETT University of Glasgow, School of Physics and Astronomy

PROF KOBUS KUIPERS Delft University of Technology, Head of Quantum Nanoscience Department

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• OUR INDUSTRY COLLABORATORS

INDUSTRY REPRESENTATIVES PROF MARKYS G CAIN

DR JAMES WATTS

Electrosciences Ltd

Flann Microwave Ltd

PROF CHRIS LAWRENCE

PROF IAN J YOUNGS

QinetiQ Group plc

DSTL

DR ADRIAN JANSSEN

DR HEATHER LEWTAS

Oclaro technology Ltd

Culham Centre for Fusion Energy

RUTH VOISEY Dyson

The students and academics involved in the Centre for Doctoral Training come from different disciplines, different universities and different cultures and are creating a fantastic environment with an extremely high-calibre of applied research.

• OUR ACADEMIC NETWORK IN THE UK AND BEYOND • THE SUPPORTING DEPARTMENTS OF THE UNIVERSITY OF EXETER • EPSRC

As an early-stage research engineer in industry, I can appreciate what additional skills, aside from my technical specialism, I could have benefitted from (and still would!) that XM2 provides today’s PGRs. Working in industry can benefit from specific research knowledge, but most often requires greater breadth beyond one’s expertise, and it is most valuable to be able to apply the problem-solving skillset developed through a PhD to tackle new problems, in areas one might not have encountered before. Looking back at my own experience I can appreciate that taking the move from postgraduate studies to industry can be daunting. XM2 offers the students a plethora of opportunities to broaden their skillset, both from a technical and soft skill perspective, all of which is invaluable to any career progression. It is a privilege to sit on the Oversight Board and to be a part of this exciting development. In 2018 we will see the first cohort finish their PhD studies and I have no doubt that XM2 has done an exemplary job of preparing them for their future careers. Good luck!

…for making the exceptional happen!

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www.exeter.ac.uk/metamaterials metamaterials@exeter.ac.uk +44 (0)1392 726568

@XM2_CDT

2017CEMPS040

/CDTMetamaterials

EPSRC Centre for Doctoral Training in Metamaterials 2017/18  
EPSRC Centre for Doctoral Training in Metamaterials 2017/18