We will establish a UK quantum device prototyping service, focusing on design, manufacture, test, packaging and rapid device prototyping of quantum photonic devices. QuPIC will provide academia and industry with an affordable route to quantum photonic device fabrication through commercial-grade fabrication foundries and access to supporting infrastructure. QuPIC will provide qualified design tools tailored to each foundry's fabrication processes, multiproject wafer access, test and measurement, and systems integration facilities, along with device prototyping capabilities. The aim is to enable greater capability amongst quantum technology orientated users by allowing adopters of quantum photonic technologies to realise advanced integrated quantum photonic devices, and to do so without requiring in-depth knowledge. We will bring together an experienced team of engineers and scientists to provide the required breadth of expertise to support and deliver this service. Four work packages deliver the QuPIC service. They are: WP1 - Design tools for photonic simulation and design software, thermal and mechanical design packages and modelling WP2 - Wafer fabrication - Establishing the qualified component library for the different fabrication processes and materials and offering users a multi-project wafer service WP3 - Integrated device test and measurement - Automated wafer scale electrical and optical characterisation, alignment systems, cryogenic systems to support single-photon detector integration) WP4 - Packaging and prototyping - Tools for subsystem integration into hybrid and functionalised quantum photonic systems and the rapid prototyping of novel, candidate component designs before wafer-scale manufacturing and testing The design tools (WP1) will provide all the core functionality and component libraries to allow users to design quantum circuits, for a range of applications. We will work closely with fabrication foundries (WP2) to qualify the design libraries and to provide affordable access to high-quality devices via a multi-project wafer approach, where many users share the fabrications costs. Specialist test and measurement facilities (WP3) will provide rapid device characterization (at the wafer level), whilst packaging and prototyping tools (WP4) will allow the assembly of subsystems into highly functionalised quantum photonic systems.

Modern society depends massively on the generation, processing and transmission of vast amounts of data. It is predicted that by 2025, 175 zettabytes (175 trillion gigabytes) of data will be generated around the globe, with so-called 'edge computing' devices creating more than 90 zettabytes alone. Processing such huge amounts of data demands ever increasing computational power, memory and communication bandwidth - demands that cannot be sustainably met by conventional digital electronic technologies. The growing gap between the needs and the capabilities of today's information technology is exemplified if we consider the historical trend in total number of computations (in units of #days of calculating at a rate of 1 PetaFLOP/s) needed to train various artificial intelligence (AI) systems. The trend followed Moore's Law (doubling approximately every two years) until 2012, after which the doubling time reduced to a mere 3.4 months! This trend is compounded by the breakdown in Koomey's Law, which states that the number of computations per Joule of energy doubles around every 1.5 years. This law was also followed until quite recently, but we are now approaching a widely accepted computing efficiency-wall at around 10 GMAC/Joule (a MAC is a multiply-accumulate operation) for CMOS electronics and the von-Neumann architecture. As a result, the energy consumption used in training modern AI systems is truly staggering, with consequent adverse effects for sustainability. This has led to a move away from standard CPU designs in AI towards the use of co-processors - GPUs, ASICs, FPGAs - with superior parallelism. However, even here the limitations of electrical signalling lead to massive levels of energy consumption. It was recently estimated, for example, that the training of a large GPU-based natural language processing system used for accurate machine translation resulted in carbon dioxide emissions equivalent to lifetime use of 5 cars! Clearly, a new approach is needed. Thus, in the APT-NuCOM project we will develop a highly efficient novel non-von Neumann co-processor that exploits clear advantages offered by photonic computation, but at the same time links seamlessly with the electronic domain to enable integration with existing electronic computing infrastructure. The APT-NuCOM co-processor will exploit novel phase-change photonic in-memory computing concepts to deliver massively parallel computation at PetaMAC/s speeds and, ultimately, an energy budget approaching that of the human brain.

Hybrid polaritonics combines the properties of different light emitting materials - organic polymers and semiconductors - in order to produce quasiparticles that combine the possibilities of both systems. "Polaritons" are quasi-particles that arise from strong coupling between light and matter. This means that they have hybrid properties, combining the mobility and flexibility of light, with the possibilities of interactions due to the matter component. At high enough densities, or low enough temperatures, polaritons can form a macroscopic coherent quantum state, a polariton condensate, or a polariton laser. Such a coherent state shows much of the same physics as Bose Einstein Condensation, as has been seen for cold atoms, but without requiring the ultra-low tempeatures required for atoms. Hybid polaritonics focuses on how, by combining different "matter" parts of the polariton, one can push these temperatures even higher, up to room temperature, and how one can engineer completely tunable system. The matter part of a polariton can come from any material which will absorb and emit light at a specific wavelength. Much existing work on polaritons is based on the material being inorganic semiconductors. These can be grown controllably, and one can drive such devices by passing an electrical current through them to make a polariton laser. However, the coupling between matter and light in semiconductors is not strong enough for these devices to work at room temperature. In contrast, organic molecules and polymers can show huge coupling strengths, but are generally poor electrical conductors. Our programme is to combine the benefits of both systems to provide a whole set of devices, operating at room temperature, based on the formation of polaritons. These devices will range from polariton lasers (providing a route to easily tunable lasers with very low threshold currents), to Terrahertz light sources (with applications in non-invasive medical imaging and explosives detection), to ultra-efficient light emitting diodes. To reach these ambitious objectives, we need to combine expertise from a wide number of fields. Our team contains world experts in light emitting polymers, semiconductor growth, characterisation and spectroscopy of polaritons, and in theoretical modelling. Members of our team have previously achieved the first realisations of polariton lasing, of strong coupling with organic materials, and of building hybrid polariton lasers. The possibility to combine this expertise draws on the unique strengths that the UK currently has in this area, and enables the combination of this expertise to be focussed on providing room temperature devices based on hybrid polaritonics, and to revolutionise this field.

Topic of Centre: This i4Nano CDT will accelerate the discovery cycle of functional nanotechnologies and materials, effectively bridging from ground-breaking fundamental science toward industrial device integration, and to drive technological innovation via an interdisciplinary approach. A key overarching theme is understanding and control of the nano-interfaces connecting complex architectures, which is essential for going beyond simple model systems and key to major advances in emerging scientific grand challenges across vital areas of Energy, Health, Manufacturing (particularly considering sustainability), ICT/Internet of things, and Quantum. We focus on the science of nano-interfaces across multiple time scales and material systems (organic-inorganic, bio-nonbio interfaces, gas-liquid-solid, crystalline-amorphous), to control nano-interfaces in a scalable manner across different size scales, and to integrate them into functional systems using engineering approaches, combining interfaces, integration, innovation, and interdisciplinarity (hence 'i4Nano'). The vast range of knowledge, tools and techniques necessary for this underpins the requirement for high-quality broad-based PhD training that effectively links scientific depth and application breadth. National Need: Most breakthrough nanoscience as well as successful translation to innovative technology relies on scientists bridging boundaries between disciplines, but this is hindered by the constrained subject focus of undergraduate courses across the UK. Our recent industry-academia nano-roadmapping event attended by numerous industrial partners strongly emphasised the need for broadly-trained interdisciplinary nanoscience acolytes who are highly valuable across their businesses, acting as transformers and integrators of new knowledge, crucial for the UK. They consistently emphasise there is a clear national need to produce this cadre of interdisciplinary nanoscientists to maintain the UK's international academic leadership, to feed entrepreneurial activity, and to capitalise industrially in the UK by driving innovations in health, energy, ICT and Quantum Technologies. Training Approach: The vision of this i4Nano CDT is to deliver bespoke training in key areas of nano to translate exploratory nanoscience into impactful technologies, and stimulate new interactions that support this vision. We have already demonstrated an ability to attract world-class postgraduates and build high-calibre cohorts of independent young Nano scientists through a distinctive PhD nursery in our current CDT, with cohorts co-housed and jointly mentored in the initial year of intense interdisciplinary training through formal courses, practicals and project work. This programme encourages young researchers to move outside their core disciplines, and is crucial for them to go beyond fragmented graduate training normally experienced. Interactions between cohorts from different years and different CDTs, as well as interactions with >200 other PhD researchers across Cambridge, widens their horizons, making them suited to breaking disciplinary barriers and building an integrated approach to research. The 1st year of this CDT course provides high-quality advanced-level training prior to final selection of preferred PhD research projects. Student progression will depend on passing examinable components assessed both by exams and coursework, providing a formal MRes qualification. Components of the first year training include lectures and practicals on key scientific topics, mini/midi projects, science communication and innovation/scale-up training, and also training for understanding societal and ethical dimensions of Nanoscience. Activities in the later years include conferences, pilot projects, further innovation and scale up training, leadership and team-building weekends, and ED&I and Responsible Innovation workshops

With decades of proven success, lasers have become central to many technologies used in manufacturing, communications, medicine and entertainment. Yet laser research continues, advancing current laser technology and developing new types of non-conventional light sources for new applications. We have just pioneered nanophotonic lasers on a graph, formed by nanostructured polymer waveguide meshes, akin to nano-scale spider webs. These are efficient lasers, with a complex emission spectrum composed of many different colours emitting in many directions, that can be understood and tailored using network theory. They also have a unique sensitivity to the illumination profile, which we can use to control the lasing spectrum, and for example reach single colour emission. We now want to push this research into III-V semiconductor laser platform, where lasers are more robust and can be designed with specific topologies. We will employ machine learning and mathematical graph theory to tailor the lasing characteristics, and achieve deterministic spectral, temporal and directional control of the lasing emission. Our goal is to develop tuneable and multi-function lasers, which can be easily integrated into next-generation lab-on-chip devices, able to support the growth of future on-chip optical computation, information technology and diagnostic tools for healthcare. Being able to switch on and off their emission could enable data processing with >10 GHz speeds, and it could act as an optical transistor for analogue optical computing, as re-programmable processing units for neuromorphic computing, for data security, novel imaging and diagnostics technologies taking advantage of their very narrow spectral lines and high sensitivity.