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HMG

Government of the United Kingdom
Country: United Kingdom
16 Projects, page 1 of 4
  • Funder: UKRI Project Code: EP/E028209/1
    Funder Contribution: 79,578 GBP
    Partners: HMG, Lancaster University

    We are trying to make semiconductor lasers for the mid-infrared (2-5 um) spectral range for a variety of practical applications including; chemical process control, environmental monitoring of atmospheric pollution and free space optical communications. At present it is impossible to obtain laser emission at room temperature due to low internal efficiency within the active region of the device. One way of minimising the unwanted processes that compete with the light generation is to arrange for this to take place inside a very small volume of material which is called a quantum dot . Recently at Lancaster we have successfully produced some quantum dot structures which emit light, but to be effective for use in a laser we need to make a sheet containing a large number of small quantum dots. The proposed fellowship seeks to build on our recent successful results and to obtain expert assistance from Dr. Solov'ev from the Ioffe Institute in Russia who is a world-leading authority in this area. Dr. Solov'ev's group has produced a dense array of self-assembled InSb quantum dots having a mean diameter of ~ 2.5 nm and a sheet density of ~ 10^12 cm-2 using a special technique to produce the InSb quantum dot nanostructures in the sub-monolayer thickness range. Dr. Solov'ev has developed a strong international lead by demonstrating room temperature light emission from his InSb quantum dot nanostructures and is enthusiastic to collaborate with us to develop a room temperature mid-infrared laser which contains these quantum dots in the active region.

  • Funder: UKRI Project Code: EP/G000190/1
    Funder Contribution: 73,530 GBP
    Partners: Kidde PLC, Lancaster University, HMG, NTUA

    We are interested in the incorporation of nitrogen into semiconductors such as GaAs, InAs and GaSb. This is important because the band gap of the parent III/V semiconductor is substantially reduced by the incorporation of very small amounts of nitrogen. These so-called dilute nitrides show promise for use in tailoring the wavelength and efficiency of novel semiconductor lasers and other optoelectronic devices. Although GaAsN and InGaAsN are currently being studied mainly for their applications in photodetectors and lasers in the 1.3 to 1.55 um telecomms wavelength range there is far less research into dilute nitride compounds for the mid-infrared (2-5 um) spectral range which is rich in applications. However, there are problems associated with incorporation of N and degradation of the crystalline quality and especially as nitrogen content in the material is increased beyond 1%. This project seeks to investigate the growth of dilute nitrides for the mid-infrared spectral range using growth from the liquid phase rather than from the gas phase.One key advantage of this approach is that we do not need any N plasma to introduce the nitrogen atoms and so we can avoid all the damage from the energetic N ion species generated as a by-product from the plasma source normally used in vapour phase growth. Liquid phase epitaxy (LPE) is well known to produce material of excellent crystalline perfection. The proposed project seeks to build on our existing expertise in LPE growth and mid-infrared optoelectronics at Lancaster and study the resulting material properties of GaAsN, InAsN, GaSbN with a view towards evaluating their potential for use in mid-infrared optoelectronic devices. We aim to investigate both bulk materials and also corresponding dilute N nanostructures. The preparation of dilute N III-V alloys with high quantum efficiency would be a real breakthrough, particularly for use within mid-infrared light sources and detectors for which there are many practical applications. Moreover, if the approach proves successful it can be readily extended to other technologically important alloys such as InGaAsN and GaAsPN.

  • Funder: UKRI Project Code: EP/D50225X/1
    Funder Contribution: 260,889 GBP
    Partners: HMG, University of Leeds, NPL, Teraview Ltd

    This work is aimed at creating new types of portable sources and detectors of radiation. These will be handheld, about the size of a normal torch, and will run off batteries. They work in the terahertz (THz) range, this can be thought of either as very high frequency radio waves or as light which is invisible to the human eye. For a long time it has been quite difficult to generate and detect THz, but over recent years people have used large powerful lasers to create pulses of THz radiation. This has proved very useful in medical applications to build up pictures of body tissue, rather like an x-ray, which can show up abnormalities. Other interesting areas being studied include using THz in fossil imaging, analysing chemicals and gases, in security and in astronomy.The work in the project aims to make a new generation of THz 'torches' and 'cameras' which can be carried in the pocket. Making the devices, small, low power and portable, will allow people to use THz radiation in applications like airport security to screen for explosive chemicals or drugs, to look for pollution in the local environment, and even to be used in pharmacies or GPs for helping with diagnosis. Moreover the radiation they use will be very 'pure' and that will help to make very sensitive detection.A feature of the work is to build upon the optoelectronic technologies developed for optical communications systems which provides a good foundation of advanced fabrication techniques leading to high reliability components capable of low power and efficient room temperature operation. UCL, Bath and Essex will work together with the Centre for Integrated Photonics (CIP), to design, fabricate and characterise novel components for THz operation. Leeds will focus on users and applications issues undertaking a detailed comparison between the performances of old and new systems.

  • Funder: UKRI Project Code: EP/D502225/1
    Funder Contribution: 1,182,840 GBP
    Partners: University of Essex, HMG, Teraview Ltd, NPL

    This work is aimed at creating new types of portable sources and detectors of radiation. These will be handheld, about the size of a normal torch, and will run off batteries. They work in the terahertz (THz) range, this can be thought of either as very high frequency radio waves or as light which is invisible to the human eye. For a long time it has been quite difficult to generate and detect THz, but over recent years people have used large powerful lasers to create pulses of THz radiation. This has proved very useful in medical applications to build up pictures of body tissue, rather like an x-ray, which can show up abnormalities. Other interesting areas being studied include using THz in fossil imaging, analysing chemicals and gases, in security and in astronomy.The work in the project aims to make a new generation of THz 'torches' and 'cameras' which can be carried in the pocket. Making the devices, small, low power and portable, will allow people to use THz radiation in applications like airport security to screen for explosive chemicals or drugs, to look for pollution in the local environment, and even to be used in pharmacies or GPs for helping with diagnosis. Moreover the radiation they use will be very 'pure' and that will help to make very sensitive detection.A feature of the work is to build upon the optoelectronic technologies developed for optical communications systems which provides a good foundation of advanced fabrication techniques leading to high reliability components capable of low power and efficient room temperature operation. UCL, Bath and Essex will work together with the Centre for Integrated Photonics (CIP), to design, fabricate and characterise novel components for THz operation. Leeds will focus on users and applications issues undertaking a detailed comparison between the performances of old and new systems.

  • Funder: UKRI Project Code: EP/T02612X/1
    Funder Contribution: 415,416 GBP
    Partners: Moogsoft, TREL, HMG, University of Oxford

    Large-scale wireless networks are expected to become prevalent in various Internet-of-Things (IoT) applications involving environment sensing and monitoring, communications, and computing. It is a fundamental task of many networks to deduce the network topology, both during the establishment of the network and periodically as the network state evolves. The availability of network topology and performance information is crucial for the operation and management of large wireless systems comprising low-power devices that are required to provide low-latency, high-reliability services. For example, state-of-the-art smart meter networks require this information to carry out routing and resource scheduling tasks, and the estimation of the number of devices in a network is useful for finding out how many sensors are still active or for detecting failures of some subnetworks. Inferring topology information even possess great importance in matters of national security in which one may have to learn the structure of a target network passively from external observables, such as the spectral activity of devices, without having access to the network devices and protocols. Many network characteristics can be inferred by observing end-to-end data, which often takes the form of packet probes. The general field of study concentrating on such techniques is known as "network tomography". Over the past twenty years, this field has been developed to include the inference of link loss statistics (loss tomography), internal queuing delays (delay tomography), and structural characteristics (topology tomography). Much of the work to date has focused on the formulation of optimal and efficient estimation methods that are primarily geared toward computer networks that exhibit certain constraints on their topologies. Some more recent studies of network tomography have considered wireless systems. However, investigations have largely been limited by the lack of available statistical models that incorporate spatial and physical characteristics inherent to wireless networks. For example, spatial (wireless) networks exhibit distinctive features (e.g., transitivity, clustering), which have not been fully exploited in topology inference tasks. This project is concerned with developing improved active methods (topology discovery) and passive techniques (topology inference) of obtaining the topology of a wireless communications network or a portion thereof. The underlying hypothesis is that probabilistic knowledge of structural properties of wireless networks can be used as prior information to improve network inference tasks, particularly topology tomography, in practical systems. The project will begin with fundamental research into the correct modelling and statistical characterisation of wireless networks designed for particular applications, such as smart meter infrastructure and tactical systems. The results of this research will be exploited to develop new topology tomography algorithms that are optimised for use in the chosen applications. The technical contributions of the project will be accompanied and supported by a number of activities aimed at delivering impact through dissemination and technology transfer. The project is supported by three hands-on partners (Toshiba, Moogsoft, and HMGCC), each of which is at the leading edge of its respective field.