School of Physics & Astronomy

Find a PhD Project Here

Opportunities for fully funded PhD or EngDoc research projects are available in all fields of research within the School. You may search for current projects on this page. APPLY HERE for a PhD Place.

 PhD in Photonics
 PhD in Condensed Matter
 PhD in Astrophysics

Search current PhD opportunities in the School of Physics & Astronomy:-




Photonics

Optimisation of interferometry-based volume holography for industrial applications
Di Falco, Prof Andrea - adf10@st-andrews.ac.uk
Turnbull, Prof Graham - gat@st-andrews.ac.uk

Joint project between School of Physics and Astronomy and ceres Holographic Ltd.

Volume holograms based on photopolymers are one of the most promising platforms to develop commercial applications of holographic optical elements at industrial level. Ceres Holographics’ unique approach uses a bespoke interferometric process to create volume phase holograms in a proprietary photopolymer. The process is high yield and reliable and produces state-of-the-art holograms. A key factor to enhance further the quality and potentials of the manufacturing technique is to fully address the optical response of the photopolymer and minimise the occurrence of unwanted artefacts.

The aim of the project is to develop a detailed model of the photopolymer to unveil the relevant polymerisation and diffusion processes and to understand the optimum timing/exposure requirements. The investigation will be complemented by an extensive experimental activity, exploiting the facilities available in the School of Physics and Astronomy of the University of St Andrews and at Ceres Holographic.

The project funds in full a four years long PhD studentship, including fees and a stipend for eligible students. Successful applicants will be part of a small yearly cohort that will meet for networking, technical and MBA courses as well as professional skills workshops.

Essential Criteria:
Degree in physical science (1st or 2:1 honours degree in physics or a related subject)
Background in Applied Optics
An interest in experimental physics

Desirable Criteria:
Knowledge of photochemistry
Programming skills for the automation of experiment and data analysis

Working Environment
Ceres Holographic and the School of Physics and Astronomy are located in the North Haugh scientific hub in St Andrews, at walking distance from each other. Academically, the student will be co-supervised by the Organic Semiconductor group and the Synthetic Optics group, who manage the cleanroom facilities in the School and have access to a large suite of characterisation laboratories. The student will have daily access to, and is encouraged to make maximum use of, the holographic fabrication and characterisation facilities at Ceres Holographics.
organic semiconductor polariton light emitters
Samuel, Prof Ifor - idws@st-andrews.ac.uk
Turnbull, Prof Graham - gat@st-andrews.ac.uk

When light is confined on the nanoscale it is possible to observe light-matter interactions that are not normally observed in bulk materials. One example is the strong coupling of photons and excitons in wavelength-scale microcavities which leads to a number of unusual phenomena [1,2]. The modes of the cavity couple with the exciton to make a hybrid-light-matter state called a polariton. One can make polaritons lasers that emit coherent light [3] and it has been shown that polaritons can form a Bose-Einstein condenstate [4].

This project will explore the properties of polaritons in microcavities based on organic semiconductors [2,4-6]. It will involve the fabrication of microcavities that include J-aggregate dyes or semiconducting polymers to explore how the energy states of organic materials can be modified when coupled to the cavity modes, and be applied in photonic devices including lasers and LEDs.

[1] C. Weisbuch et al., Phys. Rev. Lett. 69, 3314 (1992)
[2] D.G. Lidzey et al., Nature 395, 53 (1998)
[3] S. Christopoulos et al., Phys. Rev. Lett. 98, 126405 (2007)
[4] J D Plumhof, T Stöferle, L Mai, U Scherf & R F Mahrt, Nature Materials 13, 247–252 (2014)
[5] T. Schwartz, J. A. Hutchison, C. Genet, and T. W. Ebbesen, Phys. Rev. Lett. 106, 196405 –(2011)
[6] S Kéna-Cohen*, S A. Maier and D D. C. Bradley, Advanced Optical Materials 1, 827–833, (2013)
Plastic Lasers
Samuel, Prof Ifor - idws@st-andrews.ac.uk
Turnbull, Prof Graham - gat@st-andrews.ac.uk

Conjugated polymers are a very special class of plastics that are both semiconducting and efficient light-emitters. They have been widely applied as flat and flexible light emitting displays, as well as visible lasers, optical amplifiers, solar cells and electronic circuits. As novel laser media, polymers are particularly attractive because they can be easily and inexpensively formed into flexible shapes and structures that are inaccessible to crystalline materials.

This project builds on our internationally recognised research programme in polymer lasers. We have demonstrated plastic lasers driven by a light-emitting diode and are currently developing lasers and optical amplifiers integrated with nitride LEDs and CMOS control electronics. Novel photonic nanostructures are used to control
laser emission, develop new modes of operation and applications in sensing and datacomms.
Smart lighting technology for growing algae
Turnbull, Prof Graham - gat@st-andrews.ac.uk

"Dial a wavelength" for exploiting the algal cell factory

This multi disciplinary project will be undertaken in collaboration with Prof Christine Edwards at Robert Gordon University, and Xanthella ltd in Oban. The project will include a substantial industrial placement at Xanthella to integrate and test the new lighting technology in Xanthella's photobioreactors.

Microalgae are of value in a wide array of applications including pharmaceuticals and food supplements. Most algae use light energy and CO2 for growth, providing valuable by-products whilst sequestering waste CO2. They are of increasing interest as components of the Circular Economy as sustainable solutions for food, energy and water security. Photobioreactors can be used to grow algae, making use of surplus electricity from renewable power generation, however, new smart-lighting systems are needed that can optimise production.

In this project a novel wavelength-tunable lighting system will be developed to provide broad spectrum illumination to the hotobioreactor, and/or can switch to target production of individual pigments including chlorophylls, carotenoids, phycobiliproteins. LEDs will be combined with a custom-built optical system to deliver light throughout the growth reactor. The impact of illumination wavelength will be assessed initially in laboratory-scale growth tests before subsequent scale-up and integration in industrial photobioreactors.

The main activities of the project will be designing and building the lighting system and algal growth tests. Training on algal culture and compound analysis will be undertaken at RGU. Once laboratory-scale tests have identified suitable growth methodologies, the lighting system will be adapted for integration with Xanthella's commercial 100 L and 1000 L photobioreactors.
Advanced Imaging for the Biomedical Sciences (with Dr F Gunn-Moore, School of Biology)
Cizmar, Dr Tomas - tc51@st-andrews.ac.uk
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk

the aim of this project is to explore new routes for imaging both in vitro and in vivo using concepts of light transmission through disorder. In turn this will allow us to shape light at will for example at the end of an optical fibre and use this perhaps in an endoscopic scenarios. Other forms of microscopy to consider will involve using a light sheet for imaging larger biological systems (eg embryos). The study will involve advanced photonics, numerical studies and practical work. The research will also investigate strategies to image beyond the diffraction limit. Samples under investigation will include tissue and, at later stages of the work, potentially neuronal cells/tissue to target advanced understanding of neurological disease using these methods.
Advanced microscopy of nanolaser particles
Schubert, Dr Marcel - ms293@st-andrews.ac.uk

Nano- and microlasers have recently gained attention as novel light sources for biomedical applications, including single cell barcoding, refractive index sensing and tissue-integrated pressure sensors [1-3]. Their unique properties renders these devices ideally suited for experiments inside living specimens where many physical process related to development and disease are poorly understood.

Over the past decade, light sheet microscopy has revolutionized our understanding of the development of complex biological organisms [4]. While representing one of the most powerful and innovative microscopy techniques, light sheet microscopes are also typically build from scratch which allows to integrate a vast range of imaging modalities.

In this project, advanced 3D imaging will be combined with the broad capabilities of bio-integrated nanolaser. The goal is to correlate the spectroscopic information of the nanolasers with structural properties of the biological sample, by building a custom-made light sheet microscope. The new instrument will be used to investigate important biological processes like e.g. single cell tracking of invasive circulating tumour cells, cardiac regeneration or pressure sensing during gastrulation. Other aspects of the project are related to applying techniques to reduce effects of scattering by using advanced beam shaping techniques. Good knowledge of optics and microscopy, as well as basic programming skills are preferred but the student will be given the opportunity to learn relevant techniques during the project.

For further information please contact Marcel Schubert [ms293@st-andrews.ac.uk] prior to application.

[1] M. Schubert, A. Steude, P. Liehm, N. M. Kronenberg, M. Karl, E. C. Campbell, S. J. Powis, M. C. Gather, Lasing within Live Cells Containing Intracellular Optical Microresonators for Barcode-Type Cell Tagging and Tracking, Nano Lett. 2015, 15, 5647.

[2] M. Schubert, K. Volckaert, M. Karl, A. Morton, P. Liehm, G. B. Miles, S. J. Powis, M. C. Gather, Lasing in Live Mitotic and Non-Phagocytic Cells by Efficient Delivery of Microresonators, Sci. Rep. 2017, 7, 40877.

[3] A. H. Fikouras, M. Schubert, M. Karl, J. D. Kumar, S. J. Powis, A. di Falco, M. C. Gather, Non-obstructive intracellular nanolasers, arXiv:1806.03366, 2018.

[4] T.-L. Liu et al., Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms, Science 2018, 360, eaaq1392.
Aligning molecules to improve efficiency in next generation organic LEDs
Gather, Prof Malte - mcg6@st-andrews.ac.uk

Organic light-emitting diodes (OLEDs) are novel type of LEDs in which electroluminescence is generated by plastic-like organic molecules. OLEDs are at the heart of modern smart phone displays and are likely to become the dominant technology for computer screens and large area TVs in the future. In addition, OLEDs are considered for general illumination, an area where efficiency is of key importance. While OLEDs can operate with close to 100% internal electron-to-photon conversion efficiency, typically less than 20-25% of the generated light is extracted into the surrounding air; the rest is trapped in waveguided modes and eventually lost to absorption.

Various strategies have been proposed to improve light extraction from OLEDs. Very recently controlling the average orientation of the electroluminescent molecules inside an OLED has been identified as a promising avenue. However, accurate measurement of molecular orientation is difficult and it remains unclear how molecular orientation can be controlled efficiently. Within this project, these challenges will be approached by making use of different spectroscopic and computational methods. Provided certain formal criteria are met, the student can benefit from placement with a major commercial developer of OLED materials and technology.

Further reading:
Biophysical Aspects of Photodynamic Therapy
Brown, Prof Tom - ctab@st-andrews.ac.uk
Wood, Dr Kenny - kw25@st-andrews.ac.uk

Photodynamic Therapy (PDT) is a treatment for cancer that involves light-activation of a photosensitiser and causes cell death by release of singlet oxygen and free radicals. The Scottish PDT Centre was established in Ninewells Hospital, Dundee in 2000 thanks to a generous donation from the Barbara Stewart Charitable Trust. Since its introduction in Dundee, over 2,000 treatments have been carried out. The photosensiters used for PDT also have the property that they fluoresce and so they can be used for photodiagnosis (PD), which is performed at the Scottish PDT Centre to direct the surgeon towards tissue that is likely to be cancerous.
The purpose of the proposed PhD program is to gain a fuller understanding of the interaction between the incident light and the tumour. Optimal treatment regimes have not been established. We would like to be able to model both PDT and PD. To assist in this, we propose to develop theoretical radiation transfer models using Monte Carlo techniques in order to simulate the incident light and the fluorescent emission. This will be done for the range of tissue types where PDT is performed in Dundee. This includes skin (the most accessible), the oral cavity, the brain and bladder.
The work will also find application in a wide range of other areas in the drive towards minimally invasive and highly targeted therapies. In addition to the PDT described above, the techniques can be applied to so-called ‘caged compounds’ that are a range of biologically active compounds that are activated with light. In order to apply such compounds within a therapeutic environment, understanding the light tissue interactions is of key importance.
Light distribution measurements will be made around a range of light delivery devices, including cylindrical diffusers and miniature balloons filled with light-scattering media. Further measurements will be carried out using optical fibres embedded in tissue samples and using ultrashort pulses to probe two-photon activation at depth within the body. Fluorescent emission spectra will also be measured using a specially constructed optical biopsy system.

This project provides many opportunities for the student to study PDT and other light activated therapies from theoretical, experimental, and clinical perspectives.
There will be joint supervision from Dr Harry Moseley, who is Technical & Scientific Director of the Scottish PDT Centre and Honorary Reader at the University of Dundee, and Drs Tom Brown and Kenny Wood, who are Lecturers in the Department of Physics and Astronomy at the University of St Andrews. Dr Wood will supervise the theoretical aspects of the PhD (Monte Carlo radiation transfer), Dr Brown the experimental light tissue studies and Dr Moseley will supervise the clinical applications at Ninewells Hospital.

Giant Rydberg polaritons
Ohadi, Dr Hamid - ho35@st-andrews.ac.uk

Exploiting the laws of quantum mechanics for the benefit of humanity in the so-called "second quantum revolution" is one of the greatest challenges of the 21st century. For this we need to efficiently produce particles, control their states, detect them and make them interact strongly at the single-particle level. Photons, the quantum particles of light, are one of the most promising candidates. We can easily detect and control their states and we can efficiently produce them individually. However, making them interact strongly to build a large quantum network is a notoriously difficult task because photons do not interact at low energies. To make them interact indirectly, one can hybridise them with other massive particles that strongly interact and form quasiparticles called 'polaritons'.

In this project, we aim to hybridise photons with Rydberg excitons [1]. Rydberg excitons are highly excited (principal quantum number n~20) electron-hole pairs that can span macroscopic dimensions. Because of their macroscopic dimensions they strongly repel. The semiconductor device that we have chosen for hybridisation is a 2-dimensional semiconductor microcavity formed by two highly reflective mirrors encapsulating a cuprous oxide microcrystals and thin film. Photons confined in the microcavity strongly couple to Rydberg excitons in cuprous oxide to form Rydberg polaritons. This will allow us to explore quantum optics at the single-particle limit and form 2-dimensional networks of strongly correlated photons for future quantum simulators.


[1] Kazimierczuk et al, Nature 514, 343 (2014).
Hawking radiation in the laboratory
Koenig, Dr Frieder - fewk@st-andrews.ac.uk

Black holes can be understood in a simple picture: Imagine a river flowing towards a waterfall with ever increasing flow speed. Also imagine fishes in the river swimming upstream. At some position in the river the maximum speed of the fish will equal the flow speed and all fish beyond that "point of no return" will be flushed into the waterfall. Here the flow speed corresponds to the gravity of a black hole and the point of no return to the event horizon.
Arguably the most facinating aspects of astronomical black holes is the emission of Hawking radiation from the event horizon, an intriguing quantum effect combining gravity, thermodynamics and quantum mechanics.

Unfortunately, the astrophysical Hawking radiation is far too weak to ever being detected directly. Recently, however, we have invented a method to create moving artificial event horizons with short pulses in optical fibers. Moreover, the expected Hawking radiation is strong enough to be detectable with single photon coincindence counting.

The idea of the PhD programme is the calculation, detection, and characterization of this elusive Hawking radiation for the first time. The work has already gained momentum in our group and a setup is built using optical pulses of just a few cycles pulse length. In addition we will explore further quantum field theory effects in curved spacetime.
Linear and nonlinear properties of 3D optical Metamaterials.
Di Falco, Prof Andrea - adf10@st-andrews.ac.uk

Metamaterials (MMs) are man made materials with engineered optical properties. They are made assembling their artificial atoms at a scales much smaller than that of light, so as to appear homogenous. They are at the basis of very thought provoking proposals, including super imaging and cloaking applications.
In the group of Synthetic Optics we have developed a large portfolio of fabrication techniques for one- and two-dimensional MMs.

The aim of this project is to develop the fabrication protocol and applications of three-dimensional MMs obtained with a bottom up approach. The student will combine the extraordinary physical and optical properties of silica based aerogels with the flexibility of the design of nanoplasmonics to realise effective materials with bespoke optical behaviour. The aerogel is an ultra light material with refractive index close to unity and thermally more insulating than air. Combining these features with the field enhancement offered by infiltrated metallic nano particles is specially suited to address nonlinear effects at ultra-low powers.

This challenging but rewarding project requires a thorough understanding of the physics involved and the experimental rigour to fabricate and test the MMs, but offers the student the chance to learn a broad range of design, fabrication and experimental techniques.

Living Lasers: Lasing from biological cells
Gather, Prof Malte - mcg6@st-andrews.ac.uk

Optical phenomena in biological structures have fascinated mankind for centuries and biological materials with optical functionality are currently a major topic of research. In the future, photonic devices may indeed be based on natural or genetically engineered optical function.

Recently, we developed a biological laser – a device based on a single living cell genetically programmed to produce the fluorescent protein GFP. The laser is biocompatible and biodegradable, and thus offers unique physical and biological properties not shared by any existing device.

However, so far our biolasers require an artificial resonator and an external pump source. This project is aimed at gaining a better understanding of lasing and stimulated emission in biological materials and at developing new avenues to biolasers. For example, this can include the study of bio-assembled resonators based on naturally occurring structures, photophysical investigations aimed explaining why fluorescent proteins are such efficient laser materials, or the development of biocompatible nanolasers.

The project is inter-disciplinary, involving photonics, laser physics, genetic engineering, proteomics, and material science and adequate training in these fields will be provided within the school and through external collaborators.

Further reading
Millimetre wave radar signatures of drones

The detection of small unmanned aerial vehicles (UAVs), or drones, is a growing requirement both for the management of intentional drone activity and for the detection of unwanted drones which might cause a risk to security, safety or privacy. Radar is one of the most promising sensors with which drones can be detected and classified by using distinct radar signatures such as radar cross section (RCS) and micro-Doppler (produced by the rotation of the propeller blades). Research in the Millimetre Wave Group has shown that millimetre wave radar may offer some advantages in drone detection, tracking and classification in terms high Doppler sensitivity and compact system size. This PhD project aims to deepen the understanding of the millimetre wave radar signatures of drones and develop techniques which could be applied in a drone detection system. The scope of research topics includes:-

1. Develop statistical fluctuation models to analyse RCS characteristics of drones at millimetre-wave frequencies using data available at St Andrews.
2. Characterise RCS values of drones in terms of fuselage and propeller material, size, shape and aspect angles.
3. Study polarisation dependencies of the RCS values of the drones at millimetre-wave frequencies by using the available data and acquiring more data by using radars available at St Andrews.
4. Develop EM scattering models of commercial drones to study and characterise the micro-Doppler signatures produced by the propellers. Understanding of the features will be further strengthened by lab-based controlled environment experimental data collection and analysis.
5. Wavelet analysis of the micro-Doppler signatures of drones. Develop wavelet signature based drone classification algorithm for real-time application.
6. Inverse Synthetic Aperture Radar (ISAR) imaging of drones using high resolution range profiles (HRRP) data. Study the feasibility of distinguishing attached payloads and different models of drones using ISAR data.
7. Develop techniques for Neural Network based drone classification algorithm for real-time application. Extensive data is already available at St Andrews to create a training database. The candidate will also design and set up experimental trials to make the database larger and more diverse in terms of number of drones and surrounding environment.

The candidate should have a degree in Physics or Electronic Engineering, ideally with some knowledge of radar, signal processing or microwave technology. Familiarity with MATLAB and C programming would be an advantage.

The Millimetre Wave Group (https://www.st-andrews.ac.uk/~mmwave/) is extremely well equipped with test equipment, measurement facilities including an outdoor test range with dedicated lab, and a large array of components and subsystems enabling rapid development. We have built 13 radar systems at frequencies of 24, 77, 38, 94, 220 and 340 GHz, many of which would be available for data collection in this project.

If you are interested in this PhD project please contact the supervisor Dr Duncan A. Robertson (dar@st-and.ac.uk) to discuss it further.
Millimetre wave radar signatures of drones
Robertson, Dr Duncan - dar@st-andrews.ac.uk

The detection of small unmanned aerial vehicles (UAVs), or drones, is a growing requirement both for the management of intentional drone activity and for the detection of unwanted drones which might cause a risk to security, safety or privacy. Radar is one of the most promising sensors with which drones can be detected and classified by using distinct radar signatures such as radar cross section (RCS) and micro-Doppler (produced by the rotation of the propeller blades). Research in the Millimetre Wave Group has shown that millimetre wave radar may offer some advantages in drone detection, tracking and classification in terms high Doppler sensitivity and compact system size. This PhD project aims to deepen the understanding of the millimetre wave radar signatures of drones and develop techniques which could be applied in a drone detection system. The scope of research topics includes:-

1. Develop statistical fluctuation models to analyse RCS characteristics of drones at millimetre-wave frequencies using data available at St Andrews.
2. Characterise RCS values of drones in terms of fuselage and propeller material, size, shape and aspect angles.
3. Study polarisation dependencies of the RCS values of the drones at millimetre-wave frequencies by using the available data and acquiring more data by using radars available at St Andrews.
4. Develop EM scattering models of commercial drones to study and characterise the micro-Doppler signatures produced by the propellers. Understanding of the features will be further strengthened by lab-based controlled environment experimental data collection and analysis.
5. Wavelet analysis of the micro-Doppler signatures of drones. Develop wavelet signature based drone classification algorithm for real-time application.
6. Inverse Synthetic Aperture Radar (ISAR) imaging of drones using high resolution range profiles (HRRP) data. Study the feasibility of distinguishing attached payloads and different models of drones using ISAR data.
7. Develop techniques for Neural Network based drone classification algorithm for real-time application. Extensive data is already available at St Andrews to create a training database. The candidate will also design and set up experimental trials to make the database larger and more diverse in terms of number of drones and surrounding environment.

The candidate should have a degree in Physics or Electronic Engineering, ideally with some knowledge of radar, signal processing or microwave technology. Familiarity with MATLAB and C programming would be an advantage.

The Millimetre Wave Group (https://www.st-andrews.ac.uk/~mmwave/) is extremely well equipped with test equipment, measurement facilities including an outdoor test range with dedicated lab, and a large array of components and subsystems enabling rapid development. We have built 13 radar systems at frequencies of 24, 77, 38, 94, 220 and 340 GHz, many of which would be available for data collection in this project.

If you are interested in this PhD project please contact the supervisor Dr Duncan A. Robertson (dar@st-and.ac.uk) to discuss it further.
MM-wave Radar, Components and Techniques
Smith, Prof Graham - gms@st-andrews.ac.uk

MM-waves represent the area of the electromagnetic spectrum that sits between microwaves and Terahertz frequencies. It is the part of the spectrum where electronics meets optics and a wide variety of physical techniques are used to design components and systems. MM-waves are used in high resolution radar, fusion diagnostics, earth resource studies, magnetic resonance and security systems.

The mm-wave group at St Andrews is one of the largest and most well established groups in this field in the UK, and has a strong track record in designing components, sub-systems and full system. Much recent work ahas concentrated on developing radar imaging systems for earth resource studies (imaging volcanos, monitoring rainfall) and for various security related systems.
There is also a very strong program in mm-wave magnetic resonance.

A variety of PhD topics are always available and any interested student should get in touch with Dr Graham Smith in the first instance.
New photonics tools unravel the mysteries and mechanics of biological cells
Gather, Prof Malte - mcg6@st-andrews.ac.uk

Biologists have compelling evidence that in addition to biochemical signals, mechanical forces have a major impact on a wide range of processes in cell biology, with examples ranging from cell migration and cell growth to the spreading of cancer and the differentiation of stem cells. However, there is at present a shortage of suitable tools to measure the force exerted by a cell which often is well below 1nN (i.e., < 10-6 N (!)).

By developing a novel optical micro-cavity-based sensor technology, the Gather Lab seeks to overcome current limitations in measuring cellular forces and – for instance – investigate the mechanics involved in the formation and the growth and repair of nerve cells.

The basic working principle of our sensors is to detect shifts in the resonance frequency of a micro-cavity due to mechanical forces applied by cells cultured on the sensor. These shifts can be detected with high spatial and temporal resolution and the forces at play are then computed from this by a finite element method.

A PhD in the field of cellular mechanics provides you with a broad, interdisciplinary skill set: You will learn and apply a range of micro- and nano-fabrication methods and work in a state-of-the-art cleanroom. You will use different types of optical spectroscopy and work with atomic force microcopy. You will receive hands-on training in cell culturing techniques and perform studies of e.g. stem cell differentiation.

The project is part of an international collaboration with leading scientists at Harvard Medical School and University of Cambridge which is funded by the Human Frontier Science Program, the leading funding institution for interdisciplinary and international collaborative research into complex biological systems.

 
Non-reciprocal optics
Schulz, Dr Sebastian - sas35@st-andrews.ac.uk

In contrast to traditional, reciprocal optical systems, non-reciprocal systems allow the realization of interesting physical effects, for example optical isolation or the breaking of seemingly fundamental physical limits, such as the link between a system’s delay and its bandwidth [1]. Typically, non-reciprocal optical elements are realized using magneto-optic materials, for example in a Faraday Rotator. However, these materials are not suitable for integration in nanophotonic devices and thus new methods of achieving non-reciprocity need to be explored, for example nonlinear optical effects or time-variant modulations [2-4].

This project addresses the realization of on-chip non-reciprocal optical elements, new applications enabled by these elements and the exciting new physics achieved by combining non-reciprocal elements with components such as absorbers, emitters or resonators [1].

You are expected to have an interest in studying fundamental concepts in physics as well as mastering hands on nanofabrication and laboratory techniques. The project includes collaborations with groups across Europe and North America, offering you opportunities to visit the laboratories of collaborators and to build your own professional network.

The project will be supervised by Dr. Sebastian Schulz, who will join the department in March 2018. For more details on this topic and for any question regarding the project, please contact Dr. Sebastian Schulz (Sebastian.Schulz@cit.ie).

[1] H. Tsakmakidis, L. Shen, S. A. Schulz, X. Zheng, J. Upham, X. Deng, H. Altug, A. F. Vakakis and R. W. Boyd “Breaking Lorentz reciprocity to overcome the time-bandwidth limit in physics and engineering” Science 356, pp1260-1264 (2017). http://science.sciencemag.org/content/356/6344/1260

[2] E. A. Kittlaus, N. T. Otterstrom and P. Rakich “On-chip inter-modal Brillouin Scattering” Nature Communications 8, p.15819 (2017). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5504300/

[3] L. Feng, M. Ayache, J. Huang, Y.-L. Xu, M.-H. Lu, Y.-F. Chen, Y. Fainman and A. Scherer “Nonreciprocal Light Propagation in Silicon Photonic Circuit” Science 333, p. 729 (2011). http://science.sciencemag.org/content/333/6043/729

[4] D. L. Sounas and A. Alu “Non-reciprocal photonics based on time modulation” Nature Photonics 11, p 774 (2017). https://www.nature.com/articles/s41566-017-0051-x
Nonlinear Optical Micromanipulation
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk

New uses of trapped colloid as nonlinear media and uses for observations of soliton-like waves and new forms of in-situ imaging as well as nonlinear processes (eg 4 wave mixing). This is a very exciting project based on novel ordering of colloidal particles in the presence of light fields as well as the use of these colloids as new media for nonlinear effects.
OLED micro-displays as biophotonic platform
Gather, Prof Malte - mcg6@st-andrews.ac.uk

Organic Light Emitting Diodes (OLEDs) are novel optoelectronic devices with potential applications ranging from displays (e. g. in smart phones or for flexible screens) to general illumination. In contrast to conventional LEDs, OLEDs are based on plastic-like organic materials. Thus, they can be mechanically flexible and are believed to offer improved biocompatibility.

In this project, micro-displays based on >200,000 individual OLEDs, each smaller than a single biological cell, are used as a platform for advanced studies in cell biology. Potential applications include lens-free, low-cost, continuous microscopy of cells and structured illumination for optogenetic studies. Optogenetics is a technique which allows controlling the biological activity of genetically modified cells by exposure to light. Over the past decade, the technique has greatly improved the understanding of various fundamental processes in biology, in particular in neuroscience. OLED micro-displays may enable optogenetic experiments, like stimulating growth or movement of neurons, with improved temporal and spatial control, higher degree of parallelization and over longer times than currently possible.

This project is highly interdisciplinary involving photonics and materials science but also cell biology and genetics. Training will be provided in all these aspects from within my group and through collaboration with the School of Biology and external collaborators at University of Cambridge and Harvard Medical School.

Further reading:
optical antennas for visible light communications (Li-Fi)
Samuel, Prof Ifor - idws@st-andrews.ac.uk
Turnbull, Prof Graham - gat@st-andrews.ac.uk

Visible light communications is an emerging field that aims to deliver high-bandwidth wireless data through solid-state (LED) lighting. This project will be part of a multi-disciplinary research collaboration between the Universities of St Andrews, Strathclyde, Edinburgh, Oxford and Cambridge which will develop the next generation VLC technology.

The aim of this project will be to develop nanophotonic hybrid light sources and detectors based on luminescent polymer films. The student will design novel optical antennas, and fabricate these using thin film depostion and nanoimprint lithography. Working with the partner universities, these components will be combined with gallium nitride LEDs and CMOS detectors to develop next generation tranceiver technologies for visible light communications.
Optical Imaging of Biological Specimens
Brown, Prof Tom - ctab@st-andrews.ac.uk

ptical imaging can provide detailed information about a range of biological specimens from whole animals to small tissue samples. A drawback however is that such imaging often only provides data from structures at or near the surface. By contrast Optical Coherence Tomography (OCT), a low coherence interference imaging technique, can provide detailed information on tissue structure at depths of a few mm with resolution of around 10 um in living animals.

In this project we will apply OCT to a range of biological specimens to provide information which has proved to be unobtainable using other techniques. In particular the project will use OCT to provide information on tissue regeneration in amphioxus (fish-like marine chordates with close affinity to vertebrates) which are used as a model for testing concepts in nerve cord growth and repair. We will also apply OCT to Antarctic Krill (Euphasia superba), perhaps the key species in the Antarctic food web. The information these studies provide will be used to develop advanced models for acoustic imaging Krill and may also support studies on the effects of global climate change on this key species. We may also apply the system to recently launched studies of surface vasculature in Southern Elephant Seals to support ongoing studies into the diving physiology of this species.

The projects described are interdisciplinary and will require an open mind and a willingness to work with partners within Biology and Marine Science in the UK and at the Australian Antarctic Division. Australia. In order to fully develop our systems and to enable in vivo testing some travel and extended stays may be required to partner institutions.

The main supervisor for the project will be Professor Tom Brown in the School of Physics, with co-supervision by Dr Ildiko Somorjai within the School of Biology.

Prospective students should have a good background in Physics with an interest in applying their work in other fields. We are also interested in applications from students in Biology who have a strong background in imaging techniques.

Examples of the application of OCT to Krill can be found at:

M.J. Cox, S. Kawaguchi, R. King, K.Dholakia and C.T.A. Brown, “Internal physiology of live krill revealed using new aquaria techniques and mixed optical microscopy and optical coherence tomography (OCT) imaging techniques”, Marine and Freshwater Behaviour and Physiology, 48, p. 455 (2015)

N. Bellini, M.J. Cox, D.J. Harper, S.R. Stott, P.C. Ashok, K. Dholakia, S. Kawaguchi, R. King, T. Horton and C.T.A. Brown, “The Application of Optical Coherence Tomography to Image Subsurface Tissue Structure of Antarctic Krill Euphausia superba”, PLOS ONE, 9, Art. No. e110367 (2014
Optical manipulation: air/vacuum trapping for cavity optomechanics
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk

Optical trapping leads to the confinement of microscopic and nanoscopic objects using light. In the domain of optomechanics we would like to cool small "trapped" mechanical oscillators down to the quantum regime. This project aims to experimentally explore new ways to levitate and trap microparticles in air and vacuum. The ultimate aim is to slow down or 'cool' spheres to the ground state of motion. The topic is currently one of the most exciting and rapidly growing areas of physics and will involve both theory and experiment.
Optomechanical Metasurfaces for Biophotonics Applications
Di Falco, Prof Andrea - adf10@st-andrews.ac.uk

The Synthetic Optics group (www.st-andrews.ac.uk/physics/synthopt) in the School of Physics and Astronomy at the University of St Andrews has a large portfolio of research projects aimed at designing and exploiting light matter interactions at the nanoscale. The range of applications targeted is equally wide and includes the development of advanced materials, nonlinear and complex photonic and biophotonics applications. All these strands converge in the newly funded project “AMPHIBIANS”, which aims at developing a novel biophotonic platform based on the all optical manipulation of photonic metasurfaces in microfluidic environments. This experimental PhD project will focus on the design and fabrication of the photonic metasurfaces.

The current trend in biophotonics is to try and replicate the same ease and precision that our hands, eyes and ears offer at the macroscopic level, e.g. to hold, observe, squeeze and pull, rotate, cut and probe biological specimens in microfluidic environments. The bidding to get closer and closer to the object of interest has prompted the development of extremely advanced manipulation techniques at scales comparable to that of the wavelength of light. However, the fact that the optical beam can only access the microfluidic chip from the narrow aperture of a microscopic objective limits the versatility of the photonic functions that can be realized.

AMPHIBIANS aims to introduce a new biophotonic platform based on the all optical manipulation of flexible photonic metasurfaces. These artificial two-dimensional materials have virtually arbitrary photonic responses and have an intrinsic exceptional mechanical stability. This cross-disciplinary project, bridging photonics, material sciences and biology, will enable the adoption of the most modern and advanced photonic designs in microfluidic environments, with transformative benefits for microscopy and biophotonic applications at the interface of molecular and cell biology.

This experimental project is a unique opportunity for a motivated individual to work at the forefront of a cross-disciplinary and timely topic. The project is challenging but highly rewarding as it gives to the student the opportunity to learn different and highly valued skills, from the advanced design of nanophotonic devices, to the fabrication and characterisation of metasurfaces in the visible range and their applications to biological problems.
Organic light-emitting diodes
Samuel, Prof Ifor - idws@st-andrews.ac.uk

Visible light emission can be stimulated by applying a voltage to a thin layer of an organic semiconductor. The light emitted provides a window on the physics of the material, enabling us to learn about the nature of the excited states in the material. It is also useful for information display, lighting, and even for the treatment of skin cancer. We have developed a new class of light-emitting organic semiconductor, which could be used for high efficiency lighting, thereby reducing energy consumption.
Organic Solar Cells
Samuel, Prof Ifor - idws@st-andrews.ac.uk

The energy crisis is probably the most important problem facing the world today. Sunlight is the most abundant renewable energy source, but at present the cost of photovoltaics is too high for solar cells to be a serious alternative to fossil fuels. Organic semiconductors offer the prospect of low cost solar cells, but their efficiency needs improvement. We are working on new measurements to understand organic solar cell operation, and new materials to improve it.
Quantum interferometry
Koenig, Dr Frieder - fewk@st-andrews.ac.uk

Interferometers are the most sensitive instruments for measuring length. This was demonstrated by the LIGO collaboration by the direct detection of gravitational waves, which was awarded the Nobel prize in 2017.

One might wonder what the limit of precision is in an optical interferometer. The answer is that the precision is limited by the combined effect of quantum uncertainty in the phase of light and quantum-radiation pressure on the mirrors of the interferometer. This is normally referred to as the standard quantum limit.

Manipulating cleverly the quantum state of light used in the interferometer, this limit can be overcome though. The typical idea is to inject a squeezed state of light into the interferometer to reduce the quantum noise in the single variable that is read out. However, this technique is susceptible to losses and noise in the squeezed state preparation and light detection.

Recently, an alternative way has been demonstrated, an SU(1,1) interferometer, in which the beam splitters of the interferometer are
exchanged with two-mode squeezers (parametric amplifiers) [3,4]. This interferometer is sensitive to losses only inside the interferometer arms, but does not require non-classical, quantum state injection or quantum-sensitive detection.

In this PhD program, the parametric process of four-wave mixing (FWM) in optical fibers is to be used to construct a robust fiber-integrated SU(1,1) interferometer with sub-shot noise sensitivity.

In the planned experiment, a strong pump light is propagated along a suitable photonic-crystal fiber. The FWM will lead to the spontaneous conversion of pairs of pump photons to two other light modes, the signal and idler beams, defined by their frequencies. If the process has very high gain and is not entirely spontaneous, but seeded by injecting a signal, high photon numbers can be achieved at the fiber output, maintaining the strong quantum correlations between signal and idler. The quantum state of light is referred to as 'bright squeezed vacuum' [1].

Thus in a second stage of the project, this light will be used in interferometry, in which the reverse FWM interaction creates nonlinear interference between the produced signal and idler beams. The increase in sensitivity compared to a linear classical interferometer scales as the square root of the photon number in the interferometer, beating the classical shot noise limits of interferometers.

The project involves pulsed as well as continuous lasers, fiber optics, spectrometry, and single photon counting.
The project will be carried out in collaboration and intellectual exchange with Prof. Chekhova at the Max Planck Institute of Light, Germany.

[1] I.N. Agafonov, M.V. Chekhova, and G. Leuchs, Two-Color Bright Squeezed Vacuum. Phys. Rev. A 82, 011801(R) (2010).
[2] Horoshko, D., Kolobov, M., Gumpert, F., Shand, I. R., Koenig, F. E. W., Chekhova, M., Journal of Modern Optics, 2019, "Nonlinear Mach-Zehnder interferometer with ultrabroadband squeezed light" https://www.tandfonline.com/eprint/8HRHTK8PJVKEGJ8ZWMTY/full?target=10.1080/09500340.2019.1674394
[3] B. Yurke, S. L. McCall, J. R. Klauder, "SU(2) and SU(1,1) interferometers", Phys, Rev. A 33, 4033, 1986.
[4] Mathieu Manceau, Gerd Leuchs, Farid Khalili, and Maria Chekhova, "Detection Loss Tolerant Supersensitive Phase Measurement with an SU(1,1) Interferometer", Phys. Rev. Lett. 119, 223604 2017.
Single photon optical eigenmodes
Mazilu, Dr Michael - mm17@st-andrews.ac.uk

Structured light is used in imaging, communication and optical micromanipulation to increase resolution, data capacity and optimise optical traps. At the single photon level, structured light offers the perfect system to study fundamental light-matter interaction such as the transfer of linear and angular momentum to microscopic objects. This theoretical study looks at the links between quantum technology and optical micromanipulation. More precisely, coherent electromagnetic radiation can take many forms in general. Indeed, any scattering and interaction of a light field with its environment will change the beam profile and the properties of the light field involved. These effects can be calculated numerically and sometimes analytically by solving the classical Maxwell’s equations. One class of solutions of Maxwell’s equations are the optical eigenmodes that constitute a natural representation of electromagnetic scattering events. These eigenmodes are orthogonal to each other and are useful to optimise beam properties such as linear and angular momentum transfer to microparticles. This is particularly interesting when designing structured illumination for optical micromanipulation, coherent control, single pixel imaging super resolution microscopy and spectroscopy. This project aims at expanding our initial research looking at the use of optical eigenmodes in the context of single photons and quantum optics. The project has a numerical and a theoretical component that together should enable the results to be applicable to experimentally relevant cases.
Single-molecule spectroscopy of organic semiconducting polymers
Penedo-Esteiro, Dr Carlos - jcp10@st-andrews.ac.uk
Samuel, Prof Ifor - idws@st-andrews.ac.uk

Organic semiconductors based on light-emitting conjugated polymers are attracting considerable interest in semiconductor physics and are emerging as exceptional ‘plastic-like’ materials for optoelectronic applications including displays, lasers and solar cells. We have recently reported the first single-molecule studies regarding the conformation of individual polymer chains in organic solvents commonly used for device fabrication [1 ,2]. Now, in this project, we aim to combine this observation method based on single molecule fluorescence spectroscopy with magnetic tweezers to apply force to the polymer chain. By merging both techniques we will be able to stretch the polymer chain at will and understand in more detail how the conformation of the polymer chain impacts its light-emission properties. The results will help to develop new solution-processing methods that improve device performance. The project is a collaboration between the groups of Prof Ifor Samuel and Dr Carlos Penedo

[1] Dalgarno, Paul A., Christopher A. Traina, J. Carlos Penedo, Guillermo C. Bazan, and Ifor D. W. Samuel. 2013. “Solution-Based Single Molecule Imaging of Surface-Immobilized Conjugated Polymers.” Journal of the American Chemical Society 135 (19): 7187–93.
[2] Tenopala-Carmona, F., S. Fronk, Gui Bazan, Ifor DW Samuel, J. Carlos Penedo. (2018) Real-time observation of conformational switching in single conjugated polymer chains. Sci. Adv. In press

Slow and structured light in nanophotonics
Schulz, Dr Sebastian - sas35@st-andrews.ac.uk

Slow light waveguides have the potential to strongly enhance light matter interactions, leading to efficient non-linear optical processes, optical switches and optical modulators amongst other applications [1]. On a photonic chip slow light is typically realized through Photonic Crystal waveguides or coupled optical resonator waveguides [2], with the speed of light typically between 1/ 10 and 1/100 of the free space value. However, all these realizations suffer from optical scattering from fabrication defects [2-4], leading to optical losses and light localization, limiting the current device performance and rendering physical concepts such as the group velocity meaningless. Yet at the same time optical information can travel through completely opaque materials, implying that the current limit – not using photonic devices in the strong scattering regime - is self-imposed.

In this project you will investigate new slow light waveguide designs, leading to further reductions in the group velocity, while simultaneously reducing the optical losses and scattering. You will address fundamental questions about the behaviour of light and information in scattering media, for example: “At what velocity does information travel through a disordered system and how is this dependent on the disorder level in the system?”. You will investigate the effect of slow light on topics at the forefront of integrated photonics research, for example the use of complex polarization states in integrated optics and how this is affected by the disorder present in real world systems.

You will learn nanofabrication, optical simulation and characterisation techniques and gain a deep understanding of complex physical systems. You will interact with collaborators both in the UK and abroad, giving you the opportunity to visit their laboratories and build your own professional network.

The project will be supervised by Dr. Sebastian Schulz, who will join the department in March 2018. For more details on this topic and for any question regarding the project, please contact Dr. Sebastian Schulz (Sebastian.Schulz@cit.ie).

[1] T. F. Krauss “Why do we need slow light” Nature Photonics 2, p 448-450 (2008). https://www.nature.com/articles/nphoton.2008.139
[2] S. A. Schulz, L. O’Faolain, D. M. Beggs, T. P. White, A. Melloni and T. F. Krauss “Dispersion engineered slow light in photonic crystals: a comparison” Journal of Optics 12, 104004 (2010). http://iopscience.iop.org/article/10.1088/2040-8978/12/10/104004/meta
[3] S. Mazoyer, J. P. Hugonin and P. Lalanne “Disorder-induced Multiple scattering in Photonic-Crystal Waveguides” Physical Review Letters 103, 063903 (2009). https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.063903
[4] L. O’Faolain, S. A. Schulz, D. M. Beggs, T. P. White, M. Spasenovic, L. Kuipers, F. Morichetti, A. Melloni, S. Mazoyer, J. P. Hugonin, P. Lalanne and T. F. Krauss “Loss engineered slow light waveguides” Optics Express 18, pp.27627-27638 (2010). https://doi.org/10.1364/OE.18.027627
Sub-THz Radar sensing of the Environment for future Autonomous Marine platforms (STREAM)

Funding for this PhD will be available from the School of Physics & Astronomy’s strategic DTP allocation or other university scholarship.

This PhD will complement the 3.5 year STREAM project, a ÂŁ1.5M EPSRC funded collaboration between the University of St Andrews and the University of Birmingham. STREAM aims to develop advanced sub-THz radar systems that will enable true autonomy for marine systems, by providing situational awareness in a dynamic sea environment and obscuring conditions

Research on autonomous ground vehicles, guided by various sensors (lidar, acoustic, radar), has existed for many decades and the technology is now relatively mature. In contrast, research in autonomous operation in the marine environment is less mature but evolving rapidly. The key enabler will be the role of advanced electronics to provide vessels with full intelligence to facilitate autonomous operation with sensing and processing capabilities superior to those of a human.

The requirements for sensing capabilities to provide situational awareness to small and medium vessels in the dynamic marine environment include (i) maintaining safety of the boat and humans and animals in the water which requires the robust all-weather day/night detection and classification of objects in the water and (ii) adaptive path planning which requires wave profiling of the local sea surface and the detection of hazardous large waves. We assert that the key sensor modality to satisfy these requirements is novel sub-THz radar operating in the 140-340 GHz frequency spectrum. Sub-THz radar offers the advantages of very high resolution sensing with very compact sensors and the ability to penetrate obscuring conditions. Such radars will be able to measure a range of parameters from the sea surface and objects within it including range, cross-range, bulk Doppler, micro-Doppler and radar cross section (RCS). This information can then be processed to detect, track and classify objects in the scene and provide information to decision making tools used in the control of autonomous vessels.

During this PhD the candidate will collaborate very closely with the wider research team of colleagues in the Sea Mammal Research Unit at St Andrews and in the Microwave Integrated Systems Laboratory (MISL) at the University of Birmingham, plus our broad range of industrial Project Partners who are supporting the project.

The research will focus strongly on the field collection of radar data at maritime locations around the UK during multiple field trips – currently there is an almost complete lack of data on sub-THz properties of the marine environment so a primary aim of the project is to collect extensive data sets. Based on these data sets, research tasks will include:

• Modelling and analysis of sub-THz sea clutter
• Modelling and analysis scattering from objects in the sea including sea mammals
• Modelling and analysis of atmospheric propagation effects in the marine boundary layer
• Development of signal processing algorithms for detection & tracking
• Development of image analysis and classification methods
• Investigation of adaptive waveform design suitable for cognitive radar operation

The candidate should have a degree in Physics or Electronic Engineering, ideally with some knowledge of radar, signal processing or microwave technology. Familiarity with MATLAB and C programming would be an advantage.

The Millimetre Wave Group (https://www.st-andrews.ac.uk/~mmwave/) is extremely well equipped with test equipment, measurement facilities including an outdoor test range with dedicated lab, and a large array of components and subsystems enabling rapid development. We have built 13 radar systems at frequencies of 24, 77, 38, 94, 220 and 340 GHz, several of which would be available for data collection in this project. The group also has EM simulation and modelling facilities including CST Microwave Studio.

If you are interested in this PhD project please contact the supervisor Dr Duncan A. Robertson (dar@st-and.ac.uk) to discuss it further.

Sub-THz Radar sensing of the Environment for future Autonomous Marine platforms (STREAM)
Robertson, Dr Duncan - dar@st-andrews.ac.uk

Funding for this PhD will be available from the School of Physics & Astronomy’s strategic DTP allocation or other university scholarship.

This PhD will complement the 3.5 year STREAM project, a ÂŁ1.5M EPSRC funded collaboration between the University of St Andrews and the University of Birmingham. STREAM aims to develop advanced sub-THz radar systems that will enable true autonomy for marine systems, by providing situational awareness in a dynamic sea environment and obscuring conditions

Research on autonomous ground vehicles, guided by various sensors (lidar, acoustic, radar), has existed for many decades and the technology is now relatively mature. In contrast, research in autonomous operation in the marine environment is less mature but evolving rapidly. The key enabler will be the role of advanced electronics to provide vessels with full intelligence to facilitate autonomous operation with sensing and processing capabilities superior to those of a human.

The requirements for sensing capabilities to provide situational awareness to small and medium vessels in the dynamic marine environment include (i) maintaining safety of the boat and humans and animals in the water which requires the robust all-weather day/night detection and classification of objects in the water and (ii) adaptive path planning which requires wave profiling of the local sea surface and the detection of hazardous large waves. We assert that the key sensor modality to satisfy these requirements is novel sub-THz radar operating in the 140-340 GHz frequency spectrum. Sub-THz radar offers the advantages of very high resolution sensing with very compact sensors and the ability to penetrate obscuring conditions. Such radars will be able to measure a range of parameters from the sea surface and objects within it including range, cross-range, bulk Doppler, micro-Doppler and radar cross section (RCS). This information can then be processed to detect, track and classify objects in the scene and provide information to decision making tools used in the control of autonomous vessels.

During this PhD the candidate will collaborate very closely with the wider research team of colleagues in the Sea Mammal Research Unit at St Andrews and in the Microwave Integrated Systems Laboratory (MISL) at the University of Birmingham, plus our broad range of industrial Project Partners who are supporting the project.

The research will focus strongly on the field collection of radar data at maritime locations around the UK during multiple field trips – currently there is an almost complete lack of data on sub-THz properties of the marine environment so a primary aim of the project is to collect extensive data sets. Based on these data sets, research tasks will include:

• Modelling and analysis of sub-THz sea clutter
• Modelling and analysis scattering from objects in the sea including sea mammals
• Modelling and analysis of atmospheric propagation effects in the marine boundary layer
• Development of signal processing algorithms for detection & tracking
• Development of image analysis and classification methods
• Investigation of adaptive waveform design suitable for cognitive radar operation

The candidate should have a degree in Physics or Electronic Engineering, ideally with some knowledge of radar, signal processing or microwave technology. Familiarity with MATLAB and C programming would be an advantage.

The Millimetre Wave Group (https://www.st-andrews.ac.uk/~mmwave/) is extremely well equipped with test equipment, measurement facilities including an outdoor test range with dedicated lab, and a large array of components and subsystems enabling rapid development. We have built 13 radar systems at frequencies of 24, 77, 38, 94, 220 and 340 GHz, several of which would be available for data collection in this project. The group also has EM simulation and modelling facilities including CST Microwave Studio.

If you are interested in this PhD project please contact the supervisor Dr Duncan A. Robertson (dar@st-and.ac.uk) to discuss it further.
The Development of Ultrafast Laser Systems
Brown, Prof Tom - ctab@st-andrews.ac.uk

Ultrafast laser systems generate short pulses of light which may last on a few femtoseconds (fs.) These lasers are used in a wide range of applications from highly sensitive metrology to the 3D imaging of biological specimens.

In this project, we will continue our develops of ultrafast laser systems based on novel-glass gain media supplied by our partners within the UK. The student will be responsible for the design and operation of new laser systems. We will also use these systems to test advanced new components including saturable absorbers based on e.g. graphene and MoS2 and testing new approaches for dispersion compensation. As the project progresses we will also investigate the development of integrated ultrafast sources combining with other staff in the School of Physics and Astronomy and further afield. The lasers developed will be used in a range of new applications including the development of new techniques in dentistry where we will replace worn out enamel using laser sintered materials.

Students undertaking this project should have an interest in lasers and photonics systems. Experience of work within an advanced photonics laboratory would be advantageous (though not necessary) and students should be prepared to work closely with collaborators around the work to develop the laser systems.

Examples of previous work within the group can be seen at:

A. Choudhary, A.A. Lagatsky, Z.Y. Yang, K.J. Zhou, Q. Wang, R.A. Hogg, K. Pradeesh, E.U. Rafailov, W. Sibbett and C.T.A. Brown, “A diode-pumped 1.5 mu m waveguide laser mode-locked at 6.8 GHz by a quantum dot SESAM”, Laser Physics Letters, 10, Art. No. 105803 (2013)

N.K. Metzger, C.R. Su, T.J. Edwards and C.T.A. Brown, “Algorithm based comparison between the integral method and harmonic analysis of the timing jitter of diode-based and solid-state pulsed laser sources”, Optics Communications, 341, p.7 (2015)

A.D. Anastasiou, S. Strafford, O. Posada-Estefan, C.L. Thomson, S.A. Hussain, T.J. Edwards, M. Malinowski, N. Hondow, N.K. Metzger, C.T.A. Brown, M.N. Routledge, A.P. Brown, M.S. Duggal and A. Jha, “β-pyrophosphate; a potential biomaterial for dental applications”, In Press, Materials Science & Engineering C (2017)


A.A. Lagatsky, Z. Sun, T.S. Kulmala, R.S. Sundaram, S. Milana, F. Torrisi, O.L. Antipov, Y. Lee, J.H. Ahn, C.T.A. Brown, W. Sibbett and A.C. Ferrari, “2 µm solid-state laser mode-locked by single-layer graphene”, Applied Physics Letters, 102, Art. No. 013113 (2013)