Optical metrology plays a vital role in an astonishing array of important research areas and applications, from basic science discovery to material processing, medicine, healthcare, energy, manufacturing and engineering. Optical metrology instruments are normally large, heavy structures that require a well-stabilised environment to maintain accuracy, stability and functionality. These physical and functional features prevent optical metrology from moving into future smart and autonomous applications across many sectors. The proposed programme aims to challenge fundamental barriers to the use of optical measurement techniques in highly integrated, smart and autonomous 'Industry 4.0' metrology applications and emerging nanotechnologies, by establishing a unique, world-leading research collaboration in the UK that brings together advanced metrology and nanotechnology. It will translate the latest advances in nanophotonics, plasmonics and metamaterials research, in which the UK has played an internationally-leading role, into metrological applications. This will have a transformational impact on optical metrology by enabling cheaper, smarter and much more compact solutions. Research will be channelled through three complementary streams: 1. Nanophotonics-enabled components for metrology. This strand of the programme will draw on the wealth of recent fundamental developments in nanophotonics, for example, the fact that surfaces patterned with subwavelength-sized features can offer exquisite control over the wavefront of propagating light. Replacing one (or several) bulky element(s) with a single surface that carries out the same (combined) function offers hugely significant savings in size and weight, complexity and robustness (e.g. against misalignment), and opportunity to develop new measurement functionalities and instrumental configurations that are not otherwise possible. 2. Novel metrology concepts for nanotechnology. We will develop two ground-breaking ideas for metrological technologies: (1) The "optical ruler", which allows for non-contact displacement measurements with potentially sub-nm resolution using a sensor that could ultimately be manufactured on the tip of an optical fibre; (2) An approach to dynamic "nano-motion imaging" based upon the scanning electron microscopy (SEM) platform, to spatially map high-frequency nano- to picometre amplitude movement. 3. Novel metrology tools for manufacturing and nanotechnology. Using the nanophotonic components and concepts described above, we will develop novel metrology tools and measurement techniques to perform in real-world, as opposed to laboratory, conditions. Target applications will include, for example, surface/geometric metrologies compatible with manufacturing tools such as diamond turning machines and multi-axis (sub-) nanometric displacement encoding for translation stages. This programme will bring together the expertise of world-leading research groups in metrology and nanophotonics, with key industrial project partners including Renishaw and Taylor Hobson. Together, we aim to address long-standing challenges for optical metrology and to develop new, disruptive metrological technologies. These advances will be vital to support the high-value manufacturing sector in the UK. The impact of this work, however, will be felt across a far broader range of disciplines, as size and weight are significant issues in, for example, instrumentation for space science, optical instrumentation for surgical applications, and robotic arm-mounted instruments.

Standard multi-kW fibre lasers are now considered 'commodity' routinely produced by multiple manufacturers worldwide and are widely used in the most advanced production lines for cutting, welding, 3D printing and marking a myriad of materials from glass to steel. The ability to precisely control the properties of the output laser beam and to focus it on the workpiece makes high-power fibre lasers (HPFLs) indispensable to transform manufacturing through adaptable digital technologies. As we enter the Digital Manufacturing/Industry 4.0 era, new challenges and opportunities for HPFLs are emerging. Modern product life-cycles have never been shorter, requiring increased manufacturing flexibility. With disruptive technologies like additive manufacturing moving into the mainstream, and traditional subtractive techniques requiring new degrees of freedom and accuracy, we expect to move away from fixed, 'fit-for-all' beams to 'on-the-flight' dynamically reconfigurable 'shaped light' with extensive range of beam shapes, shape frequency and sequencing, as well as 3D focus steering. It is also conceivable that the future factory floor will get 'smarter', undergoing a rapid evolution from dedicated static laser stations to robotic flexible/reconfigurable floorplans, which will require 'smart photon delivery' over long distances to the workpiece. Such a disruptive transition requires a new advanced generation of flexible laser tools suitable for the upcoming 4th industrial revolution. Light has four characteristic properties, namely wavelength, polarization, intensity, and phase. In addition, use of optical fibres enables accurate control and shaping in the spatial domain through a variety of well-guided modes. Invariably, all photonic devices function by manipulating some of these properties. Despite their acclaimed success, so far HPFLs are used rather primitively as single-channel, single colour, mostly unpolarised and unshaped, raw power providers and remain at a relatively early stage (stage I) of their potential for massive scalability and functionality. Moreover, further progress in fibre laser power scaling, beam stability and efficiency is hindered by the onset of deleterious nonlinearities. On the other hand, the other unique attributes, such as extended 'colour palette', extensively controllable polarisation and beam shaping on demand, as well as massive 'parallelism' through accurate phase control remain largely unexplored. Use of these characteristics is inherent and comes natural to fibre technology and can add unprecedented functionality to a next generation of 'smart photon engines' and 'smart photon pipes' in a stage II of development. This PG will address the stage II challenges, confront the science and technology roadblocks, seek innovative solutions, and unleash the full potential of HPFLs as advanced manufacturing tools. Our aim is to revolutionise manufacturing by developing the next generation of reconfigurable, scalable, resilient, power efficient, disruptive 'smart' fibre laser tools for the upcoming Digital Manufacturing era. Research for the next generation of manufacturing tools, like in HiPPo PG, that will drive economic growth should start now to make the UK global leaders in agile laser manufacturing - enabling sustainable, resource efficient high-value manufacturing across sectors from aerospace, to food, to medtech devices and automotive. In this way the UK can repatriate manufacturing, rebalance the economy, create high added-value jobs, and promote the green agenda through efficient manufacturing. It will also enhance our defence sovereign capability, as identified by the Prime Minister in the Integrated Review statement to the House of Commons in November 2020.

Southampton and Glasgow Universities currently contribute to a project entitled CORNERSTONE which has established a new Silicon Photonics fabrication capability, based on the Silicon-On-Insulator (SOI) platform, for academic researchers in the UK. The project is due to end in December 2019, after which time the CORNERSTONE fabrication capability will be self-sustaining, with users paying for the service. Based upon demand from the UK's premier photonics researchers, this proposal seeks funding to extend the capability that is offered to UK researchers beyond the current SOI platforms, to include emerging Silicon Photonics platforms, together with capabilities facilitating integration of photonic circuits with electronics, lasers and detectors. These emerging platforms enable a multitude of new applications that have emerged over the past several years, some of which are not suitable for the SOI platform, and some of which complement the SOI platform by serving applications at other wavelengths. Southampton, and Glasgow universities will work together to bring the new platforms to a state of readiness to deliver the new functionality via a multi-project-wafer (MPW) mechanism to satisfy significantly increasing demand, and deliver them to UK academic users free of charge (to the user) for the final six months of the project, in order to establish credibility. This will encourage wider usage of world class equipment within the UK, in line with EPSRC policy. We seek funding for 3 PDRAs and 2 technicians across the 2 institutions, over a 2 year period, to facilitate access to a very significant inventory of equipment at these 2 universities, including access to UK's only deep-UV projection lithography capability. During this 2 year period, we will canvas UK demand for the capability to continue to operate as an EPSRC National Research Facility, and if so, to establish a statement of need. We currently have 50 partners/users providing in-kind support to a value of to £1,705,000 and cash to the value of £173,450.

Silicon photonics is the manipulation of light (photons) in silicon-based substrates, analogous to electronics, which is the manipulation of electrons. The development cycle of a silicon photonics device consists of three stages: design, fabrication, and characterisation. Whilst design and characterisation can readily be done by research groups around the country, the fabrication of silicon photonics devices, circuits and systems requires large scale investments and capital equipment such as cleanrooms, lithography, etching equipment etc. Based at the Universities of Southampton and Glasgow, CORNERSTONE 2.5 will provide world-leading fabrication capability to silicon photonics researchers and the wider science community. Whilst silicon photonics is the focus of CORNERSTONE 2.5, it will also support other technologies that utilise similar fabrication processes, such as MEMS or microfluidics, and the integration of light sources with silicon photonics integrated circuits, as well as supporting any research area that requires high-resolution lithography. The new specialised capabilities available to researchers to support emerging applications in silicon photonics are: 1) quantum photonics based on silicon-on-insulator (SOI) wafers; 2) programmable photonics; 3) all-silicon photodetection; 4) high efficiency grating couplers for low energy, power sensitive systems; 5) enhanced sensing platforms; and 6) light source integration to the silicon nitride platform. Access will be facilitated via a multi-project-wafer (MPW) mechanism whereby multiple users' designs will be fabricated in parallel on the same wafer. This is enabled by the 8" wafer-scale processing capability centred around a deep-UV projection lithography scanner installed at the University of Southampton. The value of CORNERSTONE 2.5 to researchers who wish to use it is enhanced by a network of supporting companies, each providing significant expertise and added value to users. Supporting companies include process-design-kit (PDK) software specialists (Luceda Photonics), reticle suppliers (Compugraphics, Photronics), packaging facilities (Tyndall National Institute, Bay Photonics, Alter Technologies), a mass production silicon photonics foundry (CompoundTek), an epitaxy partner for germanium-on-silicon growth (IQE), fabrication processing support (Oxford Instruments), an MPW broker (EUROPRACTICE), a III-V die supplier (Sivers Semiconductors) and promotion and outreach partners (Photonics Leadership Group, EPIC, CSA Catapult, CPI, Anchored In). Access to the new capabilities will be free-of-charge to UK academics in months 13-18 of the project, and 75% subsidised by the grant in months 19-24. During the 2-year project, we will also canvas UK demand for the capability to continue to operate as an EPSRC National Research Facility, and if so, to establish a Statement of Need.