CoolBlue2 is a highly innovative project with a goal to develop next generation laser technology for use in the emerging field of quantum sensing. CoolBlue2's disruptive technology has the potential to transform conventional quantum sensing systems making them cheaper and more compact. We will make use of compound semiconductors, advanced materials that can be made to emit light over a wide range of wavelengths, and process them into laser chips using specialised manufacturing techniques. Our chips will emit high quality blue light, displacing current commercially available solutions due to superior performance and lower cost. The devices produced during the project will be packaged and used to verify their efficacy in existing laser cooled systems. The project will be led by CSTG Ltd in partnership with Helia Photonics, National Physical Laboratories, the University of Glasgow and Aston University.

Given the unprecedented demand for mobile capacity beyond that available from the RF spectrum, it is natural to consider the infrared and visible light spectrum for future terrestrial wireless systems. Wireless systems using these parts of the electromagnetic spectrum could be classified as nmWave wireless communications system in relation to mmWave radio systems and both are being standardised in current 5G systems. TOWS, therefore, will provide a technically logical pathway to ensure that wireless systems are future-proof and that they can deliver the capacities that future data intensive services such as high definition (HD) video streaming, augmented reality, virtual reality and mixed reality will demand. Light based wireless communication systems will not be in competition with RF communications, but instead these systems follow a trend that has been witnessed in cellular communications over the last 30 years. Light based wireless communications simply adds new capacity - the available spectrum is 2600 times the RF spectrum. 6G and beyond promise increased wireless capacity to accommodate this growth in traffic in an increasingly congested spectrum, however action is required now to ensure UK leadership of the fast moving 6G field. Optical wireless (OW) opens new spectral bands with a bandwidth exceeding 540 THz using simple sources and detectors and can be simpler than cellular and WiFi with a significantly larger spectrum. It is the best choice of spectrum beyond millimetre waves, where unlike the THz spectrum (the other possible choice), OW avoids complex sources and detectors and has good indoor channel conditions. Optical signals, when used indoors, are confined to the environment in which they originate, which offers added security at the physical layer and the ability to re-use wavelengths in adjacent rooms, thus radically increasing capacity. Our vision is to develop and experimentally demonstrate multiuser Terabit/s optical wireless systems that offer capacities at least two orders of magnitude higher than the current planned 5G optical and radio wireless systems, with a roadmap to wireless systems that can offer up to four orders of magnitude higher capacity. There are four features of the proposed system which make possible such unprecedented capacities to enable this disruptive advance. Firstly, unlike visible light communications (VLC), we will exploit the infrared spectrum, this providing a solution to the light dimming problem associated with VLC, eliminating uplink VLC glare and thus supporting bidirectional communications. Secondly, to make possible much greater transmission capacities and multi-user, multi-cell operation, we will introduce a new type of LED-like steerable laser diode array, which does not suffer from the speckle impairments of conventional laser diodes while ensuring ultrahigh speed performance. Thirdly, with the added capacity, we will develop native OW multi-user systems to share the resources, these being adaptively directional to allow full coverage with reduced user and inter-cell interference and finally incorporate RF systems to allow seamless transition and facilitate overall network control, in essence to introduce software defined radio to optical wireless. This means that OW multi-user systems can readily be designed to allow very high aggregate capacities as beams can be controlled in a compact manner. We will develop advanced inter-cell coding and handover for our optical multi-user systems, this also allowing seamless handover with radio systems when required such as for resilience. We believe that this work, though challenging, is feasible as it will leverage existing skills and research within the consortium, which includes excellence in OW link design, advanced coding and modulation, optimised algorithms for front-haul and back-haul networking, expertise in surface emitting laser design and single photon avalanche detectors for ultra-sensitive detection.

The public description for this project has been requested but has not yet been received.

Awaiting Public Project Summary

The last fifty years have seen spectacular progress in the ability to assemble materials with a precision of nanometers (a few atoms across). This nanofabrication ability is built upon the twin pillars of lithography and pattern transfer. A whole range of tools are used for pattern transfer. Lithography is a photographic process for the production of small structures in which structures are "drawn" in a thin radiation sensitive film. Then comes the pattern transfer step in which the shapes are transferred into a useful material, such as that of an active semiconductor device or a metal wire. Lithography is the key process used to make silicon integrated circuits, such as a microprocessor with eight billion working transistors, or a camera chip which is over two inches across. The manufacture of microprocessors is accomplished in large, dedicated factories which are limited to making one type of device. Also, normal lithography tools require the production of large, perfect and extremely expensive "negatives" so that it is only economical to use this technology to make huge numbers of identical devices. The applications of lithography are far broader than just making silicon chips, however. For example, large areas of small dots of material can be used to make cells grow in particular directions or to become certain cell types for use in regenerative medicine; The definition of an exquisitely precise diffraction grating on a laser allows it to produce the perfectly controlled wavelengths of light needed to make portable atomic clocks or to measure the tiny magnetic fields associated with the functioning of the brain; Lithography enables the direct manipulation of quantum states needed to refine the international standards of time and electrical current and may one day revolutionise computation; By controlling the size and shape of a material we can give it new properties, enabling the replacement of scarce strategic materials such as tellurium in the harvesting of waste thermal energy. This grant will enable the installation of an "electron-beam lithography" system in an advanced general-purpose fabrication laboratory. Electron beam lithography uses an electron beam rather than light to expose the resist and has the same advantages of resolution that an electron microscope has over a light microscope. This system will allow the production of the tiniest structures over large samples but does not need an expensive "negative" to be made. Instead, like a laser printer, the pattern to be written is defined in software, so that there is no cost associated with changing the shape if only one object of a particular shape is to be made. The electron beam lithography system is therefore perfect for making small things for scientific research or for making small numbers of a specialized device for a small company. The tool will be housed in a laboratory which allows the processing of the widest possible range of materials, from precious gem diamonds a few millimetres across to disks of exotic semiconductor the size of dinner plates. The tool will be used by about 200 people from all over the UK and the world. By running continuously the tool will be very inexpensive to use, allowing the power of leading-edge lithography to be used by anyone, from students to small businesses. The tool will be supported and operated by a large dedicated team of extremely experienced staff, so that the learning curve to applying the most advanced incarnation of the most powerful technology of the age will be reduced to a matter of a few weeks.