Components manufactured by Additive Layer Manufacture (ALM), commonly referred to as 3D printing, are increasingly being used in applications where traditional manufacturing routes are not feasible. These components benefit from in-situ monitoring and this project aims to developp techniques for embedding novel sensor components.

Distributed temperature and srain sensing within metallic ALM structures is important to monitor component health and help to predict potential failure mechanisms. The goal of this project is to investigate novel strategies that enable integration of optical fibre based sensors into metalic ALM components. The project aims to demonstrate the abiity to produce distributed arrays of metal embedded sensors with a primary goal leading towards the production of an embedded array of temeperature sensors.

Embedding strategies including fibre metalisation, ALM process optimisation, and post embedding characterisation and treatment will be considered. Initial stages of this work will concentrate on using convnetional communications grade single mode fibre, incorporating Fibre Bragg Gratings, as the core sensing technology.

Ben Michie, Bill MacPherson, Robert Maier

Optical gas sensor technologies can provide important data that can be used to infer the presence of chemical ageing processes that can occur within a hermetically sealed system. This project aims to achieve sensitive and selective gas speciation measurements while also considering the chemical and physical constraints with regards to the system within which the sensor is located.

The detection of certain gas species can provide important information of the various chemical ageing processes occurring within a system. Regarding this project’s current application, it is critical that this detection mechanism is non-extracting and non-destructive within a hermetically sealed system and is capable of achieving high sensitivity and selective measurements. The primary gases of interest are O2, NOx and COx.

Currently, the investigation of broad-band cavity-enhanced absorption spectroscopy is being conducted. The utilisation of a laser-driven light source, capable of fibre coupling, allows for broad-band light to be coupled into an optical cavity formed by two highly reflective mirrors. The light leaked from the cavity is then dispersed through a spectrometer and is detected by a photomultiplier tube. The concentration level of gases can then be determined by the optical absorption that occurs within the gas cell.

Tamer Y. Cosgun, Dr William N. MacPherson, Dr Simon Brooks (AWE)

Hollow-core anti-resonant negative curvature optical fibres exhibit extraordinary transmission capability and flexibility for delivering high peak power ultrashort laser pulses. This project aims to find and break the limits of these fibres, and to explore their great potential in high peak power applications.

When light propagates through the quasi-vacuum environment in hollow core optical fibres instead of silica in conventional fibres, transmission is no longer limited by solid materials. The anti-resonant glass layer with a “negative curvature” structure surrounding the core can confine 99% of the mode energy in the air core, providing an ultralow attenuation. The combination of these features enables ultrashort pulses to propagate through the fibre with ultralow loss and ultrahigh damage threshold. The goal of this project is to investigate and expand the capability of hollow core anti-resonant guiding fibres (HC-ARF) (provided by the University of Bath) to transmit ultrashort laser pulses in all wavelength ranges, including the characterization and improvement of their important transmission properties such as transmission loss, bending loss, dispersion, nonlinearity, polarization maintaining, mode quality, coupling efficiency, and maximum transmittable power. High-power laser applications such as laser precision manufacturing and laser medical treatment can benefit from the result of this project. In cooperation with our industrial partners, the practical applications of ultrafast laser delivered by HC-ARF is becoming more reliable, flexible and convenient by all means.

This project was supported by projects EP/M025888/1, EP/I01246X/1, EP/M025381/1, and EP/I011315 financed by Engineering and Physical Sciences Research Council, UK.

Shouyue Wu, Bartlomiej Siwicki, Richard M. Carter, Jonathan D. Shephard, Duncan P. Hand, EPSRC, Coherent, M-Solv, Litron Lasers, University of Bath, Powerlase

Distributed fibre optic sensors show great promise in applications requiring monitoring over long distances (kilometers). By taking advantage of different forms of backscattering in the fibre, a range of sensors can be produced. Rayleigh, Raman and Brillouin scattering are three mechanisms of backscatter which can occur in an optical fibre under light excitation.

Due to the fundamental mechanisms behind them, the temperature, strain (or shape, depending on the configuration) can be detected at any point along the fibre by measuring the backscatter as a function of time. Demand in a number of industries including aerospace, land transportation and offshore energy is increasing for fully distributed and accurate measurements of these quantities at both hundreds of kilometres and over shorter ranges (metres) for component monitoring. The goal of this research is to determine how accurately this demand can be met and over what distances. James Jackson, Bill MacPherson, Henry Bookey

The world's population is rapidly growing and, most importantly, at the same time is ageing. This provides a driving force for the increase in cancer, which is predicted to grow from 18.5M in 2018 to 29.5M in 2040. One of the most effective strategies to combat cancer has been the introduction of screening programmes, which enable the disease to be detected at an earlier stage when it is curable. Earlier stage disease also lends itself to minimally invasive and endoluminal surgery, with advantages in terms of reduced morbidity and better preservation of normal function.

There is an acceptance that the use of minimally invasive and endoluminal surgery will continue to grow, perhaps in conjunction with robotic-assistance. But, to deliver this ambition, appropriate surgical tools need to be developed. This includes tools for real-time diagnosis of cancer that can be coupled with ablative and excisional modalities to eradicate the disease. Combined diagnostic and ablative tools will enable microscopic disease to be detected, particularly at cancer margins where infiltrative growth is difficult to distinguish from normal tissue. Failure to eradicate such microscopic disease is usually the cause for treatment failure and cancer recurrence.

Our multidisciplinary team of physical scientists, engineers, laser specialists, and clinicians have begun to address this shortfall in surgical hardware precision by investigating a new laser-based approach ideally suited for minimally invasive and endoluminal cancer surgery. By employing "ultrashort" picosecond lasers, that deliver energy in a series of pulses only a few picoseconds long, we have demonstrated the ability to remove (ablate) tumours on a precision 2 orders of magnitude smaller than existing tools. Importantly, because the laser pulses are so short, there is no time for heat to diffuse into surrounding tissue, as is the case for existing surgical tools. Therefore, we have shown that damage to tissue around the surgical zone can be restricted to less than the width of a human hair - almost on the scale of individual cells.

On clinically relevant tissue models we have demonstrated in the laboratory that this picosecond laser ablation could provide a step change in precision resection of the bowel and hence transform endoluminal colorectal cancer surgery. Additionally, we have shown that ps laser pulses can be flexibly delivered via novel hollow core optical fibres giving confidence that endoscopic deployment can be realised and opening up new areas of minimally invasive procedures.

We now need to capitalise on this foundation and have therefore expanded our network of clinical expertise and identified new areas where our technology could be truly transformative. Neurosurgery is the ultimate test of precision, even microscopic loss of healthy tissue can have a huge impact on quality of life. In head and neck surgery, minimising resection of normal tissue allows functional preservation of speech and swallowing, positively influencing quality of life outcomes. In parallel, we aim to build on our successful results in colorectal cancer by developing novel strategies for incorporating real-time diagnostic imaging aiming towards clinical application. The proposal will take our understanding of lasers in colorectal cancer surgery towards clinical application, whilst simultaneously exploring new areas of application (Head & neck and brain cancer) where the technology is also thought to have huge potential benefit.

This is a 3 year EPSRC funded project with researchers affiliated with the AOP group in collaboration with University of Leeds and Leeds Teaching Hospitals NHS trust (EP/V006185/1, £1,231,581)

Jonathan Shephard, Robert Thomson, Duncan Hand, Rainer Beck
David Jayne, Ryan Matthew, James Moor, (University of Leeds)
Renishaw Plc, Coherent Scotland Ltd

Intra-operational tissue assessment is a key enabling technology for minimally invasive surgery. Surgeons operating along a "keyhole" or similar means of access for minimally invasive surgery need to identify different structures or diseased areas, even when these all may look similar. This work is aimed at identifying the resection margin in cancer surgery, to allow the removal of a tumour together with a margin which is just enough to ensure complete cancer excision, but without unnecessary excess tissue removal. Currently, such a surgical margin is identified using a combination of the surgeon's experience, images of various kinds taken prior to the operation coupled with any visual observations, or tactile 'feel' in the scenario of open surgery, that the surgeon can make during the operation.

Ultimate confirmation of the surgical margin relies on post-operative histopathology, where the removed tissue is assessed microscopically. Only then, will it be known if the removal has been successful or if further surgery and/or more aggressive post-operative treatment is required. These challenges are particularly acute in surgical removal of tumours from within the body.

The development of minimally invasive techniques (such as laparoscopy or operations along body ducts, such as in the rectum or colon) have removed surgical 'feel' for tissue characteristics, including assessment of surgical margin. This highlights an unmet clinical need for a quantitative, robust, reliable and evidence-based method of determining the optimal surgical margin and providing feedback to the surgeon in a way that it can be used to make decisions during the operation.

Robot-Assisted Surgery (RAS) is the next development in minimally invasive surgery and has seen rapid development in treatment of a wide variety of conditions. It offers improved clinical accuracy by giving surgeons better control of instruments and providing features such as 3D visualisation. So far, RAS has found limited application in oncological surgery, mostly because current RAS systems rely almost entirely on visual feedback, and do not provide support for clinical decision making. This work aims to provide a novel function in RAS to enhance intra-operative clinical decision making. This technology would accelerate development of RAS in many types of visceral and solid-organ surgery where visual feedback is limited or inadequate to determine surgical margins reliably.

This partnership brings together engineering researchers with two clinical specialisms and is supported by two industries, an SME in the medical sensors area and a manufacturer of surgical robots. The group will focus on two principal aims:
1. to devise a microfabricated probe deployable via a standard minimally invasive surgery instrument capable of making intra-operative mechanical measurements on the tissue surface.
2. to establish data modelling methods in order to process the real-time measurement data to produce quantitative assessment of surgical margin as intra-operative feedback to the surgeon.

This is a 3-year EPSRC funded project with researcher affiliated with: The AOP group and the Institute of Mechanical, Process and Energy Engineering (Heriot-Watt University), Edinburgh Cancer Research Centre and College of Medicine & Vet Medicine (University of Edinburgh). (EP/V047612/1 £1.2 M)

Dr Yuhang Chen (PI), Mr Hugh Paterson (UoE), Prof. Duncan Hand, Professor Bob Reuben, Mr Daniel Good (UoE), Dr Bill MacPherson, CMR Surgical, and IntelliPalp DX.

Infrared ultrashort pulsed lasers show great promise towards surgical applications, offering high precision and compatibility with minimally invasive techniques. The objective of this project is to further improve the precision and efficiency of ultrashort pulsed laser ablation of soft biological tissues, which would in turn develop current endoscopic procedures.

This project aims to further develop the application of infrared ultrashort pusled picosecond lasers within surgical environments. Laser surgery using ultrafast picosecond/femtosecond lasers can greatly enhance both the precision and effectiveness of treatment for a wide range of diseases. Highly flexible anti-resonant microstructured fibres will be used to deliver these high energy pulses as they offer both high damage thresholds and flexible, low-loss transmission, enabling high-powered endoscopic delivery within the complex structures of the body. Novel beam steering and manipulation solutions will be investigated and combined with optical monitoring technologies, ideally for implementation in a clinical environment.

Bessel beams have shown numerous advantages over more conventional focused Gaussian beams in industrial material processing applications, including less sensitivity to focal position and possessing self-healing/diffraction resistant behavior (albeit over a limited range experimentally). These traits have the potential to be of significance in minimally invasive surgical procedures, where inhomogeneity and scattering are both important considerations.

Donald Risbridger, Dr. Jonathan Shephard, Dr. Rainer Beck, Mr. Syam Mohan

The project involves fabrication of sub-mm scale Shape Memory Alloy components using a high-precision LIFT (laser-induced forward transfer) process. The fabricated actuators will be then used as a part of medical devices for precise in-vivo motion.

Shape memory alloys (SMAs) are currently manufactured either in very thin films by vapour deposition or in bulk by casting or powder metallurgy techniques. None of these processes provides the spatially controlled functionalisation required for novel medical applications. Our approach is based on an enhancement of the high precision laser LIFT (Laser Induced Forward Transfer) process – that can build components from sub-micron layers of different materials – in combination with highly localised thermal tailoring of SMA material parameters. We will use laser pulses to sequentially “print” thin “sub-voxels” of metal films onto a substrate, in order to construct voxels each consisting of a number of sub-voxel layers of different metals. Key to our concept is the use of a multi-track substrate reel-to-reel donor tape, with each ‘track’ consisting of a coating of a thin film of a different component material for an SMA alloy. By altering the laser parameters, subsequent thermal treatment will be used to provide control of interdiffusion within and between voxels providing very tight localised control of composition. 3D microstructures will hence be constructed by continuing to add additional voxels. Example applications include precise incision, tissue identification, tactile sensing for disease and tweezing, as well as more ambitious shape transformations for “unpacking” structures in situ and “intelligent” stents and patches.

Bartłomiej Siwicki (HWU), Logaheswari Muniraj (HUW), Robert L. Reuben (HWU), and Duncan P. Hand (HWU), Riccardo Geremia (Oxford Lasers Ltd.), Nick Weston (Renishaw)

We develop procedures based on ultrashort laser pulses for the successful colonic epithelial laser ablation. This is a potential alternative to overcome limitations of conventional diathermic techniques in terms of precision and thermal damage.

In the UK 40,000 people are diagnosed every year with colorectal cancer. Existing procedures for surgical treatment use relatively cumbersome electrical cutting devices to apply heat to the tissue are challenging to perform due to restricted access and a lack of fine control for the surgeon.

Infrared lasers are attractive for surgery because the water in human tissue strongly absorbs this radiation. Additionally, "ultrafast" i.e. picosecond pulsed lasers deliver energy in such short pulses that thermal effects are minimal and tissue can be ablated with the resulting crater restricted only to the area on which the pulse was incident. Therefore, by precisely and flexibly delivering the energy to specific tumorous areas they can be cleanly removed minimising both damage to surrounding tissue and the risk of bowel perforation.

Through our collaboration we will realise the full potential of novel hollow-core fibres and create a novel steerable surgical tool guided by the fluorescent marker. Our partnership consists of experts in high power laser applications and biophotonics at Heriot-Watt University and clinical expertise at the University of Leeds. Together we will exploit this technology to develop a life-saving colorectal surgical procedure transferable to other life-threatening conditions.

This work was funded through Healthcare Impact Partnership by EPSRC (grant number EP/N02494X/1).

Jon Shephard, Duncan Hand, Robert Thomson, Rainer Beck (IPaQS), David Jayne, Nick West (University of Leeds)

The ultimate aim of the work is to prove concepts for practically deployable optical elements for the endoscopic delivery of ps laser light via novel hollow core fibres. We address existing technological barriers that need to be overcome in order to move towards practical deployment in a clinical environment.

The ultimate aim of the work is to prove concepts for practically deployable optical elements for the endoscopic delivery of ps laser light via novel hollow core fibres. This follows directly on from our EPSRC project aimed at developing new laser surgical techniques for early stage colorectal tumour surgery. The overall concept that ps laser light can be used to precisely resect tumours tissue with virtually no collateral damage to surrounding healthy tissue was well proven. This project will build on these excellent results and aim to address existing technological barriers in miniaturisation and integration that need to be overcome in order to move towards practical deployment in a clinical environment.

This work is funded through Multi-modal Manufacturing of Medical Devices (4MD) by EPSRC (EP/P027415/1).

Jon Shephard, Robert Thomson, Rainer Beck, Donald Risbridger (IPaQS), David Jayne, Nick West (University of Leeds)

This project supported by Renishaw and EPSRC, is developing a laser polishing technique working to improve the surface finish of additively manufactured metal parts. This method offers advantages over currently used processing methods by allowing greater selectivity of the localised surface finish and simpler process automation for bespoke parts.

Additively manufactured components have a high surface roughness in their as-built state rendering them unsuitable for most applications without some degree of post-processing. Commonly used methods include mechanical polishing which for bespoke parts is a time-consuming semi-manual process requiring a skilled worker. Another common method is electro-chemical polishing that uses hazardous substances and is non-selective in processing area. Laser polishing addresses these challenges by using a high power laser spot to create a localised melt pool on the surface of the material. The surface tension drives the molten metal reducing the surface roughness once re-solidified. The small laser spot allows for selectivity in the processing area allowing multiple surface finishes. The dimensions of the components are defined from the build stage allowing for automation of the process increasing repeatability over other techniques.

The project has identified optimal parameters for laser polishing of titanium alloy and cobalt chrome and has progressed to polishing cranial and dental implants with a variety of sizes using a 100 W SPI fibre laser and a more cost effective fibre delivered laser diode array. We have also investigated methods of delivering beam onto internal surfaces using a prism. The tensile stresses produced in the polishing process have been relieved using standard heat treatment procedures.

Mark W. McDonald, Wojciech S. Gora, Yingtao Tian (Lancaster), David Lunt (Manchester), Stuart G. Stevenson (Renishaw), Philip B. Prangnell (Manchester), Nick J. Weston (Renishaw), Duncan P. Hand

High average power nanosecond lasers offer high throughput at the expense of process quality. This project, funded by SPI Lasers and the University, investigates laser-material interaction and processing strategies in the high power regime in order to propose an ideal system for high throughput and quality laser applications such as engraving.

Engraving of metals using moderate average power (~20W) nanosecond (ns) pulsed fibre lasers is well established. Examples of very high-quality 3D engraving are available, for instance in the creation of dies for coin manufacture, where very low surface roughness is required together with high dimensional accuracy. Although process rates are reasonable (a few cubic mm/second) there is a demand for higher productivity and hence higher average power nanosecond pulsed fibre lasers have been developed for this and other applications (100 – 200W). However, simply using similar but scaled up process parameters for these higher power lasers do not yield similar surface quality, nor even the expected process rate. This project therefore seeks to understand and overcome these issues. The work is undertaken using the current pulsed laser product range of SPI Lasers together with laser products in development. We are examining the range of physical effects that occur when using high power nanosecond pulses with different temporal shapes and peak powers, as well investigating different scanning strategies and parametric combinations that will produce fast and high-quality results.

Stephen D. Dondieu, Krystian L. Wlodarczyk, Robert L. Reuben, Duncan P. Hand, Paul Harrison (SPI Lasers), Adam Rosowski (SPI lasers), Jack Gabzdyl (SPI Lasers)

Bonding optical materials (glasses, crystals) to other optical or structural materials (metals, ceramics) is a key manufacturing challenge for many optical devices, as clearly articulated by our industrial partners. Our solution is to use an ultra-short pulsed laser welding process that has shown great promise but currently requires many months or even years of detailed experiments for each new material combination and geometry. Hence applications are currently limited to components made from borosilicate glasses or quartz welded to aluminium alloys and stainless steel, of typical dimension 10 mm.

In this project our drive is to extend the process to new combinations of materials (including important IR materials) and shapes. To achieve this, the project will take a multi-pronged approach: (i) to create the modelling and sensing tools essential for rapid process optimisation; (ii) to engineer a new optimised laser source based on emerging 2 micron wavelength technologies, pioneering the welding process for IR optical materials; (iii) to research concepts for engineering the interface and weld/joint geometry to reduce the impact of differential thermal properties of the two materials; and (iv) to investigate scaleable welding approaches for larger parts e.g. continuous meander patterns and dynamic clamping. Finally, we will undertake a series of proof-of-principle experiments to determine the suitability of the process with a wide range of material combinations, directed towards our industrial partners' applications.

Our programme of manufacturing research is aligned with the interests of our industrial collaborators, together with the academic drivers of laser material interaction knowledge, process understanding and process control. Our ultimate goal is to develop this welding process into a truly flexible and generic solution for joining optical to structural materials at a range of scales.

This is a 3 year EPSRC funded project with researchers affiliated with: The AOP Group and The Laser Device Physics and Engineering Group (EP/V01269X/1 £974k)

Duncan P. Hand, R. M. Carter, M. J. Daniel Esser, Adrian Dzipalski, Leonardo MW, Luxinar, GTS, NSG Group (UK), Oxford Lasers, The Manufacturing Technology Centre (MTC)

Manufacturing with lasers has advanced from the purely science fiction ideas of the 1950's and 60's to be a real world, critical step, in the manufacture of an enormous range of products. Over the years a range of new techniques and processes have been developed in research labs and companies across the world. One of the more important of these has been the development of beam-shaping technology.

Laser processing of material is driven by transfer of energy from the laser beam into the material, and can be a mixture of thermal, photo-chemical and optical non-linear effects. By changing the shape of a laser beam where it impacts a material it is possible to mould how and where energy is transferred. This then allows for more precise control of the laser-material interaction and hence of the manufacturing process itself.

This has led to improvements in the way cutting, welding and similar processes work with improvements in quality and efficiency. However these beam-shaping technologies are limited. They only shape in two dimensions, i.e. in a single focal plane. This is not a big problem for "surface processes" as the plane at which the laser beam is formed into the right shape can be made, with some care in focussing the beam, to be the surface of the material. However for materials with an irregular shape, imprecise thicknesses, or that are at least partially transparent to the laser, this is a challenge. It is also a challenge when trying to take advantage of the range of exciting new technologies based on non-linear phenomena.

Non-linear laser processes typically limit the laser material interaction to only those regions of the laser beam where there is an extremely high intensity i.e. at the focus. By moving the focus inside the material it then possible to manufacture from the inside out. However, because the light interacts with the material not just on the surface but throughout the focal volume two dimensional beam shaping is insufficient; full 3D control is instead required.

Within this research project we will take advantage of the wave-nature of light. Through careful shaping of a glass optic it is possible to bend different parts of a laser beam to overlap in a controlled manner. As the beams overlap they will interfere creating regions of high and low energy. Though careful calculation it is possible to manipulate this with each optic designed to give a precise interference pattern which results in a specific energy distribution; to shape the beam in three dimensions.

By shaping the laser beam throughout the focal region it will be possible to open entirely new methods of manufacture from more effective means to cut toughened glass (like mobile phones or iPads), dice and drill semiconductors (for computer chips), make precision medical devices, and create new and much more effective surgical procedures. The potential applications are truly enormous, transformative and will change how and what we can manufacture.

This is a 3 year EPSRC funded project with researchers affiliated with the AOP group, (EP/V006312/1 £586k).

Richard M. Carter, Duncan P. Hand, Jon S. Shephard, Gooch & Housego, Oxford Lasers, PowerPhotonic Ltd, St James’ University Hospital

This ERC-funded project is focused on the investigation and understanding of fluid flow and transport processes in porous rocks, for carbon capture and storage applications. Our role in this project is to manufacture physical 3D models of porous rocks out of transparent materials, that can be used to verify theoretical models.

The MILEPOST project aims to investigate and fully understand the fluid flow and reactive transport mechanisms that govern the macroscopic behaviour of complex subsurface systems (porous rocks etc) at the pore level. Our part of this project is to use ultrafast lasers to manufacture transparent physical models of porous media, including up-scaled replicas of thin sections of realistic rock structures. A single picosecond laser is used to: (i) machine microstructures directly on a glass slide and (ii) enclose these microstructures by welding a second glass slide on top.

The ultimate goal of the MILEPOST project is the development of three-dimensional porous media models with integrated sensors for the in-vivo measurements of propagation fronts, such as pressure, pH change and fluid displacement. The outcome of this research will be used to better understand the subsurface fluid flow and reactive transport processes and to validate existing numerical models of subsurface systems.

The project is led by Professor Mercedes Maroto-Valer from the Research Centre for Carbon Solutions (RCCS) at Heriot-Watt University.

Krystian Wlodarczyk, Amir Jahanbakhsh (RCCS), Omid Shahrokhi (RCCS), Rumbi Nhunduru (RCCS), Shima Ghanaatian (RCCS), Robert Maier, William MacPherson, Duncan Hand, Mercedes Maroto-Valer (RCCS)

Heriot-Watt supported by Leonardo is investigating the use of Ultrashort pulse laser welding as a means of bonding laser crystals/optics to metallic support structures and heatsinks in order to fabricate a laser without the use of adhesives to bond dissimilar materials.

Adhesive bonding, used extensively within the fabrication of lasers and optical systems, has long been known to suffer from performance and reliability issues such as outgassing, accidental contamination of optical surfaces during bonding, creep and degradation with age. This project seeks to investigate the use of Ultrafast Laser Welding as an alternative to adhesives in the manufacture of lasers and other appropriate optical systems. The short pulse length of picosecond or femtosecond lasers allows for the bonding of highly dissimilar materials such as laser crystals/optics to metallic support structures and heatsinks. To assist with the evaluation of the validity of the bonds for use in optical systems, an automated circular polariscope has been developed as part of this project to measure the stress induced optical retardation of the welded components and its effect within the part.

Samuel N. Hann, Duncan P. Hand, M. J. Daniel Esser, Robert Lamb (Leonardo), Ian Elder (Leonardo), Paulina O. Morawska, Richard M. Carter.

Bonding optical materials (glasses, crystals) to other optical or structural materials (metals, ceramics) is a key manufacturing challenge for many optical devices, as clearly articulated by our industrial partners. Our solution is to use an ultra-short pulsed laser welding process that has shown great promise but currently requires many months or even years of detailed experiments for each new material combination and geometry. Hence applications are currently limited to components made from borosilicate glasses or quartz welded to aluminium alloys and stainless steel, of typical dimension 10 mm.

In this project our drive is to extend the process to new combinations of materials (including important IR materials) and shapes. To achieve this, the project will take a multi-pronged approach: (i) to create the modelling and sensing tools essential for rapid process optimisation; (ii) to engineer a new optimised laser source based on emerging 2 micron wavelength technologies, pioneering the welding process for IR optical materials; (iii) to research concepts for engineering the interface and weld/joint geometry to reduce the impact of differential thermal properties of the two materials; and (iv) to investigate scaleable welding approaches for larger parts e.g. continuous meander patterns and dynamic clamping. Finally, we will undertake a series of proof-of-principle experiments to determine the suitability of the process with a wide range of material combinations, directed towards our industrial partners' applications.

Our programme of manufacturing research is aligned with the interests of our industrial collaborators, together with the academic drivers of laser material interaction knowledge, process understanding and process control. Our ultimate goal is to develop this welding process into a truly flexible and generic solution for joining optical to structural materials at a range of scales.

This is a 3 year EPSRC funded project with researchers affiliated with: The AOP Group and The Laser Device Physics and Engineering Group (EP/V01269X/1 £974k)

Duncan P. Hand, R. M. Carter, M. J. Daniel Esser, Adrian Dzipalski, Leonardo MW, Luxinar, GTS, NSG Group (UK), Oxford Lasers, The Manufacturing Technology Centre (MTC)