To perform astronomy, we generally require two pieces of equipment. The first is a telescope, which collects and concentrates the signal of interest from space. The second is an instrument, which analyses the properties of the signal concentrated by the telescope. The limits to the knowledge we can gain about the universe are entirely determined by the performance of these two pieces of equipment, and they are of equal importance - a good telescope with a bad instrument is of little use, and vice versa.

The performance of any instrument (e.g. sensitivity and precision) is determined and limited by the performance of the technologies that are available at the time of development. For example, if better detectors are available, instruments can be constructed that can observe fainter objects such as more distant galaxies. If more precise and stable calibration technologies are available, we can finely track small changes in the signal from a source over long time-periods, enabling us to detect small Earth-like planets, and potentially even enabling us to observe the expansion of the universe in real-time!

In order to continue to increase the performance of astronomical instruments operating in and around the optical region of the electromagnetic spectrum, we must develop new technologies that allow us to efficiently manipulate, detect and calibrate the light captured by the telescope. One option here is to exploit advanced "photonic" technologies and techniques. Photonics is the broad area of science concerned with the generation, manipulation and detection of light. Modern photonic technologies include lasers and optical fibres - technologies that have revolutionised our world. The overarching aim of this STFC Consortium Grant is to bring together a critical mass of UK experts in the fields of photonics and astronomical instrumentation, with the specific aim of securing the UK's position as a global leader in the field of "astrophotonics", and opening the way to a new generation of optical astronomical instruments with unprecedented performance.

Informed by instrumentation priorities over the coming decade, we will perform fundamental technology research in three main areas by developing:

• advanced photonic laser manufacturing techniques to fabricate monolithic glass optical sub-systems, enabling more efficient and lower cost instruments with enhanced instrument design freedom.
• versatile precision laser calibration sources that are specifically tailored to meet the demands of future astronomy, and that are suitable for widespread adoption.
• bespoke low-loss optical fibres which can be used to flexibly route light from the telescope to instruments for analysis without degrading the spatial and spectral properties of the light.

This project will lay the foundation for leading UK roles in the next generation of astronomical optical instruments. The vastly improved performance compared to current facilities will give increased scientific output, and ultimately deliver new insights to our understanding of the universe.

Accurately monitoring the flow of natural gas from a petroleum reservoir is a critical capability that enables petroleum companies to quantify the productivity of their oil and gas fields. Conventional flow meters operate on "dry gas" (in which no oil or water is present) and offer no compositional information about the gas, simply providing an average mass-flow rate. A product delivering the flow rates of individual hydrocarbons would add significant value by allowing the energy transported to be calculated, opening up new markets such as "custody transfer", in which oil and gas are transferred from one operator to another. A further generalisation would be a meter providing compositional information of "wet gas", in which oil and water are also present, as is common from gas fields that are nearing the end of their productive lifetime. Enhancing conventional flow meters with compositional information would increase the addressable market from £2.4B to £6.7B. This market is both large and timely, with customers who are able to invest in development once a working prototype has been demonstrated. It is therefore well suited to IPS funding, offering a potentially high return on investment on a timescale of 3 to 6 years.

This proposal is a partnership between Heriot-Watt University and two companies -- GM Flow, a leader in dry-gas metering, and Chromacity, which spun out from Heriot-Watt in 2013 and has commercialized our mid-infrared laser technology. STFC investment of £353K will be leveraged by direct and in-kind contributions > £400K from the industrial partners and £88K (20% FEC) from Heriot-Watt. Post-project investment of a further £400K is committed by the industrial partners to complete commercialization of the technology.

The project will lead to the commercialization of an innovative gas metering product providing laser-based multi-species gas concentration measurement, and drawing on our recent STFC-funded (ST/P00699X/1) research in this area. The vision is that by the end of the project the partners will be ready to bring to market a complete system, comprising an integrated laser and spectrometer, with fibre delivery of mid-IR light to a remote flow-meter head. Chromacity will lead the system integration, GM Flow the flow-meter design and Heriot-Watt the optical design and data processing aspects. A collaboration with the ORC in Southampton will give the project access to innovative low-loss "hollow core" mid-IR fibres, as an alternative to commercially available but higher loss fluoride glass fibres.

STFC IPS funding will be used strategically to resolve the technical or commercial "known unknowns" that currently stand as roadblocks to the technical realization of the concept or its commercialization. Technical questions which will be addressed include: understanding the range and limitations of fibre-delivered broadband light for mid-IR spectroscopy; assessing the capability and limitations of algorithms for extracting concentrations of multiple hydrocarbons; and identifying the best practical embodiments for fibre-fed spectroscopy within a flow-meter. Similarly, the project will answer commercially important questions, such as whether the measurement uncertainty provided by the technique is compatible with customer requirements. Field trials with potential early adopters will also provide vital feedback needed to define the minimum viable product acceptable by the market.

The project will leverage resources (notably a £90K Chromacity mid-IR laser) from an earlier STFC funded CLASP project project, with the main STFC funding being used for consumables and PDRA resource. As a practical knowledge exchange mechanism, the PDRA will transition in Year 3 to spending 50% of his time in Chromacity, with the associated cost met by the company.

The Extremely Large Telescope (ELT) is now under construction in the Atacama Desert in northern Chile by the European Southern Observatory (ESO). With a diameter of 39m and a greater collecting area than all current large telescopes combined, the sensitivity and spatial resolution of the ELT will dwarf those of existing facilities in the visible and infrared. With the first observations planned for 2024, the sheer sensitivity of the ELT is truly remarkable, with a collecting area over 18 times that of ESO's current largest telescopes. The telescope will also continuously correct the light from astronomical objects with a technique called adaptive optics, giving astronomers images with five times better resolution than possible today.

This vast step forward in both collecting area and image resolution from the ELT will be transformative for nearly every aspect of contemporary astronomy, from searches for molecules potentially linked to life in nearby exoplanets, out to detection of the most distant galaxies at the edge of the observable Universe. It will give us our first detailed views of individual stars in galaxies which are millions of light-years beyond the Milky Way, and help to settle arguments as to whether some of the fundamental constants of physics vary in space and time. It will have the capabilities to directly detect mature planets similar to those in our Solar System around nearby stars, while also probing the distribution of elusive dark matter in galaxies when the Universe was just 10% of its current age. This is just a small subset of the diverse and profound scientific breakthroughs we expect from the ELT, and UK astronomers and engineers are playing leading roles in the development of the cameras and spectrographs that will take the valuable observations in the mid 2020s and beyond.

Building on a decade of scientific and technical development, the UK ELT Programme coordinates the UK roles in ELT instrumentation. At the core of the programme is leadership of the design and construction of the HARMONI instrument, one of the two first-light instruments for the telescope, ensuring UK astronomers will be well prepared to reap the rewards from ELT observations as soon as possible and some of its first discoveries.

The programme also includes smaller roles in future instruments, so that UK astronomers can exploit as much as possible of the tremendous new discovery space of the ELT. The UK is building the high-resolution spectrograph for METIS, the third instrument for the ELT, now in construction (led by the Netherlands). UK groups also have key roles in design studies of the next instruments, HIRES (led by Italy) and MOSAIC (led by France), both of which will be essential to exploit the huge scientific opportunities of the observatory. Lastly, the programme is investing in research and development of new technologies that will influence the design of future ELT instruments, particularly the development of the PCS instrument for studies of exoplanets.

Our tangible cultural heritage, both historic and contemporary, is made from a plethora of complex multilayer materials. What we see is often only the surface and form of an object. Hidden below are the materials and evidence of the processes by which the objects were originally created. By using state of the art imaging / spectroscopy systems which can map the composition and reveal the stages of their creation, we gain an understanding about the meaning and significance, both in their original context and our present day. This is at the heart of the disciplines of technical art history, archaeology and material culture studies. It also informs collections care, access policies and conservation of cultural heritage.

Infrared imaging and spectroscopy is particularly well suited to looking below the surface, as the scattering which normally occurs with visible light is usually much less. Thus the infrared penetrates further into the object. Depending on the material and its structure the infrared light will be absorbed or reflected. This can either be directly imaged or modulated (Fourier Transform Spectroscopy) to acquire spectroscopic information indicating the chemical composition. Most techniques employed at present within the field of cultural heritage can only make spot measurements; to map large areas would take hours to days to acquire the data and therefore is not usually viable or suitable for in-situ measurements. Other techniques require samples to be taken and are therefore invasive. We aim to explore state of the art IR imaging strategies that will be "fit for the job". This implies wide bandwidth, full field and fast techniques coupled with signal processing/ photonics methods to analyse, visualise and manipulate large multivariate data sets. By exploiting state-of-the-art laser sources developed at Heriot-Watt and providing massively tunable infrared light, we will explore and develop several complementary strategies for 4-dimensional imaging (3 x spatial, 1 x wavelength). Compressive sensing illumination techniques and machine-learning based data processing will allow us to image rapidly and efficiently while also extracting the maximum value from our datasets by automatically classifying surface and sub-surface features.

In this way we expect to produce outcomes of shared value for both the ICT and Technical Art History researchers in our team. Contextual information from art history will inform the photonic design and computational anaylsis strategies we deploy, while powerful ICT-led techniques will provide the Technical Art History community with new technical capabilities that reveal previously hidden structure and history.

The significance to the public of our cultural heritage has motivated us to integrate outreach activity from the start, in particular a dynamic website using 4D data to allow an interactive tool for exploring the chosen case studies, reflecting the People at the Heart of ICT priority.

The project includes industrial partners who will contribute resources and expertise in mid-IR lasers (Chromacity Ltd.) and mid-IR cameras (Thales Optronics Ltd.). Our partners have committed substantial in-kind support in the form of access to their technology and contributions of staff time. Furthermore, their engagement ensures that activities within the project, and the outcomes these generate, can be rapidly evaluated for adjacent commercial opportunities.

EPSRC priorities are reflected in the project's structure. Cross-Disciplinarity is embedded as collaborations within the ICT community (Photonics & AI Technologies researchers) and with researchers from the AHRC-funded Cultural Heritage community. Co-Creation is essential: only by combining the distinct technical, contextual and material resources of each research group in our team will the project succeed in delivering new capabilities for IR imaging and analysis and new insights into culturally important objects of shared value.

Informed by the requirements of future precision atomic clocks, this project targets the development of an "optical frequency comb" -- a laser providing a thousands of regularly spaced optical frequencies which form a ruler in frequency that is a critical component in quantum timekeeping devices.

Quantum technology research in the UK and internationally is developing small atomic clocks to which the frequency of a special laser (not a laser comb) can be locked with extremely high stability. Yet these clocks "tick too fast": the clock laser oscillates at about 500 trillion "ticks per second", far too quickly to allow it to be interfaced to real-world systems like computer networks and electronic navigation devices. The laser comb can be used like a gearwheel to reduce this rate to one more appropriate for everyday applications of about 10 billion ticks per second. In this sense the comb works exactly like the clockwork mechanism in a pendulum clock, reducing the faster ticks of the pendulum to less frequent increments in the positions of the minute and hour hands.

To date, practical laser combs with the right technical characteristics have been difficult to produce, even with lab-scale dimensions. This project will address the need for compact combs as sub-systems within a practical optical clock--and the current absence of such technology--by developing a disruptive laser-comb architecture. This will be compatible with visible clock transitions in new ion-based time standards, and will have a scale suitable for integrating into quantum timekeeping devices needed by sectors from security, energy, geodesy, finance and defence.

Our approach will leverage advances in ultrafast lasers and integrated nonlinear photonic devices, complementary technologies in which the investigators at Heriot-Watt and Glasgow Universities are world leaders. Areas of emphasis are the development of robustly packaged infrared pulsed lasers operating at around 10 GHz (10 billion "ticks per second"), and the efficient extension of these to the visible region by using chip-scale "super-continuum" devices prototyped in the material gallium arsenide and finally to be made from the material silicon nitride. The output of these lasers will be made into a frequency comb by using a combination of optical and electronic stabilization techniques.

The project will be developed in close association with several academic and industrial partners who will contribute resources and expertise in lasers (Laser Quantum Ltd.), optoelectronic manufacturing (Optocap Ltd.), optical frequency metrology (NPL), optical frequency standards (EPSRC UK Quantum Technology Hub in Sensors and Metrology), optical systems engineering (Fraunhofer Centre for Applied Photonics) and expertise in end-user applications of combs (Dstl).

Publications

• Towards a space-qualified Kerr-lens mode-locked laser Ye Feng, Tobias P. Lamour, Hanna Ostapenko, Richard A. McCracken, Oliver Mandel, Dennis Weise and Derryck T. Reid OPTICS LETTERS 46, 5429-5432 (2021)

• Supercontinuum generation in orientation-patterned gallium phosphide Supercontinuum generation in orientation-patterned gallium phosphide Marius Rutkauskas, Anchit Srivastava, Peter G. Schunemann and Derryck T. Reid NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XX in Proceedings of SPIE 11670, 1167019 (2021)

• Supercontinuum generation in orientation-patterned gallium phosphide Marius Rutkauskas, Anchit Srivastava and Derryck T. Reid OPTICA 7, 172-175 (2020)