Problems during birth leading to a lack of oxygen (birth asphyxia) and subsequent brain injury (neonatal encephalopathy or NE) occur in 1-2 per 1000 full term births in the UK. An infant's health is in great danger when there is a prolonged lack of oxygen delivery to meet the metabolic demand of the brain. Perinatal brain injury remains a significant cause of neonatal mortality and is associated with long-term neurological disabilities including cognitive impairment, mental retardation and accounts for 15 to 28% of children with cerebral palsy. Monitoring the tight balance of brain blood flow, oxygen delivery and brain tissue metabolic rate is a major aim in patient diagnosis and care. Clinicians currently cannot monitor the biochemical status of theinjured brain continuously and non-invasively at the infant's cot-side. There is an urgent clinical need to detect as early as possible those neonates at most risk and who may benefit from adjunct therapies and/or redirection of clinical care for effective rehabilitation. Early detection and assessment of brain neurological status and outcome requires sensitive, robust and easy to measure biomarkers. We are proposing to take a new and creative approach to the way in which the neonatal brain is monitored and useful information is delivered to doctors. We will first develop an entirely novel portable, non-invasive brain monitoring instrument, which will allow birth asphyxiated infants to be monitored at the cot-side in the intensive care unit. This will open up new possibilities for how we guide the management of babies with brain injury. This new instrument will be based on integrating two technologies that use light to monitor the brain. The first technique is broadband near-infrared spectroscopy (or broadband NIRS) and uses low light levels of near-infrared light to measure the distribution of oxygen and blood in the brain, and how oxygen is being utilised by mitochondria the power factory of cells. The second technique is called diffuse correlation spectroscopy and uses a single wavelength (colour) of near-infrared laser light to measure the movement of the red blood cells and hence quantify brain blood flow. In particular this instrument will be able to monitor non-invasively brain blood flow, brain oxygen levels and the metabolic status of the brain tissue by measuring the electrochemical status of cytochrome-c-oxidase, an enzyme in the mitochondria. We will evaluate this instrument and measurement in the lab using a large animal model of the human neonate; after which we will move on to clinical evaluation studies in the neonatal intensive care unit. The system/instrument will be specifically designed to help doctors to quantify the injury severity and optimise the type and duration of therapies, minimise the risk of further injury to the brain, and thus improve the likelihood of the infant's recovery. In addition to building this new neuromonitoring instrument, we will also develop computer programmes which are essential to extract the relevant information from the measured signals from the brain. This will involve developing routines for delivering measurements in real time, and incorporating a computer model of the brain to help us understand the meaning and relationships of our measured signals. We have a long and successful track record of this type of translational research, i.e. the combined approach of hardware and software engineering of novel brain imaging technologies targeted at specific applications in healthcare, and introduction into clinical use. We have assembled a multidisciplinary team to meet the challenges of this ambitious project including engineers, clinicians and physicists, and we have attracted the interest of an industrial project partner for potential commercial exploitation of our developed systems.

Quantum information science is the field of research that studies the information present in a quantum system. It opens the way to the knowledge of unexplored fundamental physical mechanisms and to the development of novel technologies that will profoundly transform the way we communicate and process our data. Indeed, a number of new technological applications can be envisaged thanks to exquisitely quantum phenomena. While classical information encoding relies on bits, which can be either 0s or 1s, the quantum bits (or qubits) are associated to the state of quantum objects, e.g., single atoms, single spins, or single photons. Because of the quantum superposition principle, the qubits can then be 0s, 1s, or coherent superposition of both, thus giving access to an exceptionally richer alphabet. Quantum information science also exploits quantum entanglement, i.e., strong correlation between quantum objects, as a resource for fast and secure quantum communication protocols. In view of realizing networks for quantum communication, quantum memories are fundamental devices as they act as interfaces between the photons, used as information carriers (or flying qubits), and stationary qubits, exploited for information storage and processing. While atomic gases enabled the first remarkable quantum storage experiments, solid-state systems, and specifically rare earth ion doped crystals, also offer interesting perspectives thanks to the absence of atomic motion and the high density, and the fact that they unleash prospects of integration, which facilitates scalability and employability in real-life quantum technology demonstrations. As a matter of fact, the implementation of quantum information protocols on a small chip has the potential to replicate the revolution of modern electronic miniaturization and intense research efforts are indeed devoted to developing miniaturized photonic integrated circuits for quantum information processing. Yet, on chip memories for single photons, key components of future quantum communication technology, are currently missing. This Fellowship addresses this pressing challenge by developing waveguide quantum memories based on ultrafast laser micromachining of rare earth ion doped crystals. We will engineer the necessary tool kit for the integrated quantum memories to fulfil simultaneously all the requirements for their employability in real-life quantum networks, as on-demand read-out, high efficiency, long storage time, and multimodality. Moreover, we will demonstrate how the integrated design gives access to functionalities that are not possible with bulk devices, like the non-destructive detection of single photons. This vision represents a technological breakthrough toward the realization of complex memory-enhanced quantum photonics circuitry on chip.

Understanding the functional makeup of the brain is a holy grail of neuroscience, and imaging tools play a significant role in achieve this aim. Functional imaging is a more difficult goal than anatomical imaging because it depends on establishing a contrast mechanism that relates to physiological function and also can be measured with good accuracy and resolution. Optical techniques are very attractive because of the rich information encoded in the absorption spectra of many different molecules, but they are difficult to use at large scale because of the high degree of scattering that occurs in passing through different tissues of the body. By using time-resolved measurements of the propagation of light from multiple illumination patterns, diffuse optical tomography (DOT) can produced low-resolution images of absorption and scattering properties, and decorrelate these to produce maps of oxygenation in the brain and other organs. At the same time, diffuse correlation spectroscopy (DCS) examines the way in which coherent light is decorrelated from itself when compared over time. This decorrelation naturally occurs due to the Brownian motion of endogenous scattering particles, and blood flow. Coherent optical techniques thus allow the non-invasive monitoring of blood flow and provide an indication of pathological cerebral auto-regulation during, e.g., stroke. Until recently, limitations in coherent detection technology have prevented significant developments towards diffuse correlation tomography (DCT), wherein volumetric images of blood flow can be produced. In this project we aim to develop a system for DCT and time-resolved DOT in one device. This will bring the two techniques together to provide images of cerebral blood flow and cerebral metabolic rate of oxygen extraction in the brain for the first time. We propose the development of theoretical and experimental methods which will enable the development of a new generation of optical instruments for portable, low-cost, continuous simultaneous monitoring of blood flow and chromophore concentrations. The rich images produced by our system have the potential to vastly improve our understanding of underlying neurological processes and pathology, and to allow the efficient use of scarce resources in targeted treatments.

How can we make a movie of atoms - or even electrons - moving inside molecules? This is a fundamental problem in many fields of physics, chemistry and biology. For this, we need pulses of light with a duration which is much shorter than the characteristic times of the movements of the atoms or electrons. For the case of atoms this is typically a few femtoseconds (1fs is one billionth of a nanosecond); electrons move even faster, on the attosecond scale, where (1 attosecond is one thousandth of a femtosecond!). We also need very short wavelengths, such as those of X-rays, so to achieve the necessary resolution at the nanometre scale. Meeting these requirements is a formidable challenge, but the pay-off in terms of applications, ranging to medical science to material engineering, is enormous. Cutting-edge imaging experiments of this type have already been achieved by using X-ray sources in huge facilities. However, their large scale and operating cost prevents them from becoming a widespread tool. There is a more convenient and compact way of producing very short X-ray pulses. If we shine short pulses of visible light on a jet of gas, such as argon, the atoms of the gas respond to the presence of this light by emitting bursts of extreme ultraviolet and soft X-ray radiation by a process called "high harmonic generation" (HHG). The applicability of these pulses for probing electronic dynamics in atoms and molecules has been tested in a series of pioneering experiments. However, the brightness of HHG sources is far from being comparable with that of large-scale facilities. We will investigate the prospects for making HHG a fully viable technique for taking "molecular movies" with a system small enough for an ordinary R&D laboratory. We have identified solutions for overcoming current limitations: in particular, we will work on choosing the best possible visible light for producing HHG radiation, as well as on employing techniques of "phase-matching", i.e. controlling how the light propagates through the jet, to increase the efficiency of generation. HHG beams are akin to an X-ray laser, with which they share properties of coherence. This implies that, if we collect the full information on the amplitude and the phase of the light far from our target, we can use sophisticated computer codes to reconstruct the shape of this object. This avoids using lenses for X-rays, which are difficult to manufacture. Further, by tuning the wavelength of the X-ray beam it is possible to select and image only a specified atomic element in the object. We will demonstrate the utility of the bright HHG beams we plan to develop in proof-of-principle experiments on aluminium alloys. These alloys - which are of crucial importance to the aerospace, automotive, and electronic industries - derive their strength from the formation of inhomogeneities during heat treatment. However, the relation between their microscopic structure and mechanical properties is not well understood; our demonstration experiments may open a new route for exploring these important issues. From a fundamental viewpoint, the electromagnetic field contains the maximum possible information about an object that can be obtained in an optical experiment. Hence we will also investigate methods able fully to characterize the X-ray field scattered from an object, allowing the spatial and structural dynamics of the object to be tracked. In summary, we plan to take major steps towards laboratory-scale imaging at atomic spatial and temporal scales by developing bright, compact pulsed soft-X-ray sources and measurement methods that return the full details of the radiation field incident on, and scattered from, the object under study. This research programme therefore has the potential to deliver a step change in what is possible in spatio-temporal imaging at the nanoscale

Nanoscale quantum optics is a promising new field aimed at coherent control and manipulation of single photons emitted by individual quantum emitters in a nanostructured photonic environment. Single emitters have dimensions much smaller than the wavelength of light, and therefore interact slowly and omni-directionally with radiation, placing limits on photon absorption and emission. These intrinsic fluorescence limits can be overcome when the source is placed in a nanostructured photonic material. Multi-scale (fractal) structures are a new class of particularly interesting photonic materials, since they lead to spatial localisation of the electromagnetic energy into subwavelength areas (hot spots of 10s of nm) over a wide spectral range, which are driven by optical excitations coupled to the network on different scales. Here I propose to investigate collective plasmonic systems, based on plasmon multiple scattering and interference on metallic networks. I will study natural gold networks and artificially designed one. I will approach these structures using a network theory approach, a statistical method centred on the network topology, made of links and nodes. This method has the potentiality of describing the complex system with few robust parameters, extracted from the rich microscopic details, and thus provides much deeper understanding. The study of network optical properties will focus on probing one of the most robust modal properties: the local density of optical states. This is a key fundamental quantity involved in light-matter interaction, as it provides a direct measure for the probability of spontaneous light emission (the Purcell effect), light absorption and scattering. I propose to identify the emergent nature of the different optical modes of complex plasmonic networks by studying the statistics of the LDOS in artificial plasmonic networks. I plan to understand the inner character of the complex plasmonic modes, and to reveal subwavelength "hot-spots", critically localized states and chaotic mode signatures. This knowledge will be exploited to design and engineer the LDOS for local fluorescence enhancement and to exploit the network as an unconventional antenna to control the fluorescence of an individual colloidal quantum dot, enhance its radiation rate, boost and manipulate its directionality. I will aim at demonstrating a strong link between the plasmonic network structures, their optical properties and their effect on a light emitter.