Coherent detection and manipulation of terahertz quantum cascade lasers

Lead Research Organisation: University of Leeds
Department Name: Electronic and Electrical Engineering

Abstract

The terahertz (THz) region of the electromagnetic spectrum spans the frequency range between microwaves and the mid-infrared. Historically, this is the most illusive and least-explored region of the spectrum, predominantly owing to the lack of suitable laboratory sources of THz frequency radiation, particularly high-power, compact, room-temperature solid-state devices. Nevertheless, over the past decade, THz frequency radiation has attracted much interest for the development of new imaging and spectroscopy technologies, owing to its ability to discriminate samples chemically, to identify changes in crystalline structure, and to penetrate dry materials enabling sub-surface or concealed sample investigation.

One of the most significant recent developments within the field of THz photonics has been the THz quantum cascade laser (TQCL). These high-power compact semiconductor sources have opened up a host of new opportunities in the field of THz photonics and have attracted significant research interest world-wide. However, there is the need to develop techniques for measurement of the phase of the radiation field emitted from TQCLs, thereby providing a complementary technology to currently established incoherent detection schemes. Furthermore, there is a need to explore fully the advances that can be made through control and manipulation of the phase of the THz field emitted by TQCLs.
My vision is to initiate a range of research programmes with the aim of probing, manipulating and utilising the coherent nature of TQCL radiation. This will lay the foundations for a wealth of research opportunities in THz photonics, as well as facilitating the exploitation of THz technology for fundamental science and also for real-world applications.

I will develop both optical and electronic techniques for coherent detection/measurement of the field emitted by TQCLs. One means of achieving optical coherent detection is through the up-conversion of the phase and amplitude of the THz field into the near-infrared band with an electro-optic (EO) crystal. This approach will also allow the large field amplitudes and narrow line-widths of TQCLs to be exploited, enabling QCL radiation to be sampled using a broad-area EO crystal and a standard optical CCD. This will open up a significant range of opportunities for exploiting well developed visible/near infrared detector and CCD technologies within THz science. In parallel, I will develop coherent detection techniques by down-conversion of the THz field to radio frequencies. I will accomplish this through heterodyne phase-locking the fields from two TQCLs using a Schottky diode.

I will investigate coherent detection using self-mixing in TQCLs. This method relies on sensing junction voltage perturbations induced by feedback of the radiation field into the TQCL cavity, enabling coherent detection of the field using a single TQCL device as both source and detector. Using this approach, linewidth narrowing in TQCLs will be investigated, as well as techniques for three-dimensional 'detector-less' imaging and tomography.

I will also establish a programme concentrating on the radio-frequency control and manipulation of the THz field through the use of dynamic and static gratings, generated and controlled via the interaction of surface acoustic waves (SAWs) with TQCL devices. This approach will be used to provide a non-contact means to apply a potential modulation to TQCL devices, thereby providing a distributed feedback mechanism for the THz wave. As part of this I will develop TQCLs with reduced active regions thicknesses and TQCL mesa structures.

The combination of all these technologies will be combined to demonstrate the first 2D phase-sensitive THz tomography system using QCLs, the first full-field imaging system combining TQCLs and commercial CCD technology, and high-resolution THz gas spectroscopy.

Planned Impact

The potential impact of the proposed programme is far-reaching and would encompass academic, economic and societal aspects.

Academics, both in the UK and internationally, will benefit in the short-medium term (1-5 years) through the scientific advancements and technological developments accomplished by the proposed research. Specifically, these include: Achieving greater understanding of semiconductor lasers and detectors, the development of terahertz (THz) quantum cascade laser (TQCL) technology, the development of THz systems applicable to a wide range of research areas across the physical, chemical and biological sciences, the development of novel coherent detection and measurement techniques for TQCLs, as well as facilitating the exploitation of well-developed visible/near-infrared technologies in THz science. In addition, this programme will lead to longer-term economic impacts through the training of PhD researchers and undergraduate students in semiconductor fabrication techniques, laser photonics, and system development skills that will be directly transferable to careers in high-technology industries including telecommunications. This programme will also enhance the reputation of the University of Leeds as an international research institute, thereby improving the UK's competitiveness.

However, the impact of this programme goes far beyond this. Owing to the unique properties of THz radiation, THz systems have many potential application areas outside of academia including pharmaceutical process monitoring, airport security screening, chemical sensing, industrial inspection, non-destructive testing, and medical imaging. As such, high-technology engineering companies in the UK will benefit in the medium-long term (5-10 years) through the development of THz imaging, tomography and spectroscopy systems based on TQCL technology within this proposed programme of work. An example of such a company is Teraview, who supply Ti:sapphire-based spectroscopy systems to the pharmaceutical sector, where they are used to characterise polymorphs of drugs during development and production cycles. The technological developments from my programme would therefore have a positive impact on the UK economy through the creation and growth of such companies, and the associated creation of wealth, and also by attracting R&D investment into the UK.

The THz systems developed within this fellowship will also have potential long-term impact (>10 years) both to the public sector as well as society as a whole. For example, development of airport security screening systems (both for detection of concealed weapons and sensing of chemical substances including explosives) would have significant positive implications to national security, thereby also improving public well-being. In this respect, benefactors would also include UK governmental agencies (e.g. Home Office, HMGCC). Likewise, improved production cycles of pharmaceuticals would both improve the effectiveness of public services (the NHS) and also general quality of life and health/well-being through improved drug treatments. Other potential impacts to society, in the long-term, include the development of non-invasive medical imaging techniques as well as environmental monitoring systems, the latter of which could also have profound implications to the long-term protection of the global environment.

Through examples such as these, where societal benefits are immediately tangible, the public awareness, appreciation and understanding of science/technology will also benefit.
 
Description The aim of this grant was to initiate a range of research packages with the aim of probing, manipulating and utilising the coherent (phase-stable) nature of terahertz (THz)-frequency quantum cascade laser (QCL) radiation, for the first time. As part of this programme I developed novel phase-sensitive detection and control techniques that will lay the foundations for a wealth of research opportunities in THz photonics, as well as facilitating the exploitation of THz technology for both fundamental science and real-world applications.
Several key developments have emerged from this grant that have attracted significant interest internationally (see specific outcomes). Amongst these is the development of novel THz imaging and materials analysis approaches that exploit the self-mixing effect in QCLs. This exciting new technique enables coherent detection of THz fields using a single QCL device acting as both source and detector. As such, this approach is extremely simple and compact, and provides a fast and sensitive alternative technology to the cryogenically-cooled detectors used to date by the international community. I have exploited this coherent detection scheme to demonstrate:
1) The first two-dimensional and three-dimensional 'detectorless' terahertz imaging systems enabling, for example, imaging of concealed objects and the reconstruction of three-dimensional semiconductor structures with sub-micron resolution and fast sampling times.
2) The first apertureless scattering-type near-field microscope based on a THz QCL source. This system has achieved the highest imaging resolution (1 micron) achieved with a THz QCL to date.
3) New schemes for materials-analysis at THz frequencies based on a swept-frequency imaging approach. This approach has been applied to the identification of plastic explosives RDX, SX2 and Metabel, as well as for high-resolution imaging of biological samples including human skin. In particular, this work has shown how our technique can distinguish different tissue types and detect sub-surface features of skin tissues, to a penetration depth exceeding 100 microns, which are not visible optically.
Overall this work has resulted in numerous publications, several invited talks at key international conferences, and offers enormous potential for future industrial up-take, for example for non-invasive inspection applications. The further development and commercial opportunities of this technology are currently being explored through an EPSRC Impact Acceleration Account award (EP/K503836/1), a European Commission Proof-of-Concept grant award (ERC-PoC-2016; 727541) and in collaboration with two industrial partners: L3 Micreo and Teraview Ltd. In particular this patented technology opens a pathway towards automatic techniques for the discrimination of healthy tissue types for the study of normal physiology and possible therapeutic approaches. The application of this technology for screening of skin melanoma is currently being explored through a Medical Research Council Confidence in Concept grant (MC_PC_14109).
Several key breakthroughs have also been made concerning the technological development of THz QCL devices. These include:
4) The development of the world's first THz QCL emitting more than 1 Watt of power. This milestone in the field of THz science has attracted media interest from around the world, and has been reported in more than a dozen news outlets world-wide including the BBC website, BBC Radio Leeds, and The Times of India.
5) In collaboration with Rutherford Appleton Laboratory, the integration of THz QCL devices with mechanically robust waveguide technology suitable for applications in atmospheric science. This work is currently being developed further through funding from the European Space Agency.
6) The development of a novel frequency-tuneable QCL source exploiting the Vernier tuning effect in a coupled cavity geometry. This technology is readily applicable to multiple-frequency spectroscopic sensing approaches, including the remote identification of explosives and illicit drugs-of-abuse
7) The development of high-performance broadband InGaAs and InGaAsP-based THz sources exploiting commercially-mature laser diode technologies, in collaboration with University College London (UCL) and The London Centre for Nanotechnology. This work led to the first demonstration of injection-locking of a THz QCL using 1550nm laser technology.
8) The first measurement of the gain recovery time in a THz QCL using time-domain THz-pump-THz-probe techniques. This work has enabled the ultrafast dynamics of THz QCLs to be explored, of great relevance for the development of modelocked THz sources.
All of these innovations represent significant improvements to THz QCL device performance and, as such, are translatable to a wide range of applications across the physical sciences and industry.
Exploitation Route Overall, the wide range of developments and outcomes emerging from this grant represent a significant advancement in THz QCL-based technologies and systems, which could have far-reaching implications across a range of academic and industrial areas. Potential application areas suited to industrial exploitation include pharmaceutical process monitoring, airport security screening, chemical sensing, non-destructive testing, industrial inspection, and medical imaging. As such, these technologies are well-suited for up-take by a range of high-technology engineering companies, as well as military and government agencies. Developments will be brought to the attention of such end-users through their on-going involvement in parallel programmes at Leeds. Further development and commercial opportunities of this technology are currently being explored through an EPSRC Impact Acceleration Account award (EP/K503836/1) and a European Commission Proof-of-Concept grant award (ERC-PoC-2016; 727541). As part of this work, we are currently working with two industrial partners (L3 Micreo and Teraview Ltd) to further develop this patented technology (PCT/AU2014/000828) and explore routes to market.
Avenues for further development and translation of biomedical imaging approaches based on THz QCLs are already being pursued, in collaboration with The University of Queensland, through a Cancer Research UK Development Fund (C37059/A16369), a Medical Research Council Confidence in Concept grant (MC_PC_14109), and also through my management committee role in BMBS COST Action BM1205 'European Network for Skin Cancer Detection using Laser Imaging', a collaborative framework involving >20 international partners.
Coherent detection and phase-locking approaches for THz QCLs using compact and commercially-mature laser diode technologies will continue to be pursued through on-going collaborations with Ruhr-Universität Bochum and University College London. In particular, our recently awarded The latter is coordinating the EPSRC Programme Grant 'HyperTHz' will provide a route with which to disseminate further outcomes to industrial end-users as well as academic researchers from across the UK.
Overall, the developments in THz QCL device technology arising from this grant (high-power devices, waveguide-integrated QCLs, frequency-tuneable devices) will be taken forward over the coming years through a number of funded research programmes. These include programmes in collaboration with Rutherford Appleton Laboratory ('Integrated THz Mission for Atmospheric Sounding,' European Space Agency grant; 'Supra-terahertz technology for atmospheric and lower thermosphere,' NERC grant; 'LOCUS Critical Payload Development For Future In Orbit Demonstration,' Seventh CEOI Technology Call grant), with the aim to exploit the current state-of-the-art QCL technology for a low-cost upper-atmosphere sounder in-orbit-demonstrator mission.
The further development of THz frequency QCL sources, including novel mode-locked sources, will also be explored through a funded Horizons 2020 FET-OPEN grant (665158), in collaboration with Centre National de la Recherche Scientifique, University of Bari, University Paris Sud, and University of Regensburg.
Sectors Aerospace, Defence and Marine,Electronics,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy

 
Description Several aspects of the research funded through this grant have featured in National and International news and magazine articles. These reports have created impact, through greater understand and appreciation of science by the general public. Examples include: 1) An article featuring my self-mixing imaging technology, published in Physics World Magazine, June 2016 2) The development of the world's first terahertz quantum cascade laser emitting more than 1W of power was reported in more than a dozen news outlets world-wide including the BBC website, BBC Radio Leeds, The Times of India (national newspaper) and websites including www.phys.org.
First Year Of Impact 2014
Sector Education,Other
Impact Types Societal

 
Description Australian Research Council Discovery Project
Amount $32,000 (AUD)
Funding ID DP120103703 
Organisation Australian Research Council 
Sector Public
Country Australia
Start 01/2012 
End 01/2014
 
Description Australian Research Council Discovery Project
Amount $390,000 (AUD)
Funding ID DP160103910 
Organisation Australian Research Council 
Sector Public
Country Australia
Start 01/2016 
End 12/2018
 
Description Cancer Research UK Leeds Centre Development Fund
Amount £10,000 (GBP)
Funding ID C37059/A16369 
Organisation University of Leeds 
Department Cancer Research UK Leeds Centre
Sector Academic/University
Country United Kingdom
Start 10/2013 
 
Description EPSRC (UK) Programme Grant award; HyperTerahertz - High precision terahertz spectroscopy and microscopy
Amount £6,517,861 (GBP)
Funding ID EP/P021859/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 06/2017 
End 05/2022
 
Description EPSRC Capital Equipment grant
Amount £450,000 (GBP)
Funding ID EP/P001394/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2017 
 
Description EPSRC Impact Acceleration Account award
Amount £44,000 (GBP)
Funding ID EP/K503836/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2015 
 
Description EPSRC Responsice Mode grant
Amount £406,000 (GBP)
Funding ID EP/M01598X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2015 
End 05/2018
 
Description European Commission Horizon 2020 Marie Sklodowska-Curie Fellowship programme H2020-MSCA-IF-2015
Amount € 195,000 (EUR)
Funding ID 703912 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 03/2016 
End 03/2018
 
Description European Commission Horizons 2020 FET-OPEN, MIR-Bose
Amount € 3,786,000 (EUR)
Funding ID 737017 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 01/2016 
End 12/2019
 
Description European Commission Proof-of-Concept grant award ERC-PoC-2016
Amount € 150,000 (EUR)
Funding ID 727541 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 10/2016 
End 10/2017
 
Description European Space Agency grant
Amount £185,000 (GBP)
Funding ID Supra-THz Receiver Front-End Development 
Organisation European Space Agency 
Sector Public
Country France
Start 05/2015 
 
Description European Space Agency grant
Amount € 10,000 (EUR)
Funding ID 'Modelling and Measurement of the THz Fingerprint Spectra of Biomolecules' 4000109286/13/NL/MV 
Organisation European Space Agency 
Sector Public
Country France
Start 12/2013 
End 05/2014
 
Description Horizons 2020 FET-OPEN, ULTRAQCL
Amount £734,000 (GBP)
Funding ID 665158 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 10/2015 
End 09/2018
 
Description MRC Confidence in Concept grant
Amount £75,000 (GBP)
Funding ID MC_PC_14109 
Organisation Medical Research Council (MRC) 
Sector Academic/University
Country United Kingdom
Start 07/2015 
 
Description PhD studentship, funded by University of Leeds DTA award
Amount £60,000 (GBP)
Organisation University of Leeds 
Sector Academic/University
Country United Kingdom
Start 10/2013 
End 04/2017
 
Description PhD studentship, funded by University of Leeds DTA award
Amount £60,000 (GBP)
Organisation University of Leeds 
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 03/2019
 
Description Collaboration with Inst. of Micro- & Nanoelectronic Syst., Karlsruhe Inst. of Technol., Germany 
Organisation Karlsruhe Institute of Technology
Country Germany 
Sector Academic/University 
PI Contribution This research collaboration made possible the study of the ultrafast dynamics and transient heating effects in terahertz quantum cascade laser sources. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Access to experimental facilities including quatum cascade laser characterisation equipment; Development, characterisation and provision of high-performance quantum cascade laser
Collaborator Contribution Contributions include: Expertise in experimental aspects of ultrafast superconducting detector technologies; Development and provision of ultrafast superconducting detectors; Intellectual input to research strategy.
Impact 10.1063/1.4818584 10.1109/TTHZ.2012.2228368
Start Year 2012
 
Description Collaboration with L3 Micreo Ltd 
Organisation L3 Micreo Ltd
Country Australia 
Sector Private 
PI Contribution Expertise in experimental and theoretical aspects of quantum cascade laser sources, imaging systems and self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems, clean-room fabrication facilities, and photomixer characterisation apparatus; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution L3 Micreo Ltd will undertake the specific construction of a compact laser head using our laser technology. This will raise the technological readiness level (TRL) of our imaging technology, and increase the opportunity for commercial uptake.
Impact EPSRC Impact Acceleration Account award EP/K503836/1 (2015) European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016
Start Year 2015
 
Description Collaboration with Laboratoire Pierre Aigrain, Ecole Normale Supérieure, Université P. et M. Curie, Université D. Diderot, Paris, France 
Organisation École Normale Supérieure, Paris
Country France 
Sector Academic/University 
PI Contribution This research collaboration has made possible the study of injection-seeding and the sampling-coherence of terahertz quantum cascade laser sources. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Development, characterisation and provision of high-performance quantum cascade laser sources including dual-cavity lasers essential for these experiments; Intellectual input to research
Collaborator Contribution Contributions include: Expertise in injection-seeding of quantum cascade laser sources; Development of and access to terahertz time-domain spectroscopy apparatus enabling injection-seeding of quantum cascade laser sources; Training of visiting research staff in experimental techniques for injection-seeding of quantum cascade laser sources; Intellectual input to research strategy.
Impact 10.1109/IRMMW-THz.2012.6380209 10.1364/CLEO_SI.2012.CTu2B.5 10.1364/OE.20.016662 10.1364/OL.37.000731 Horizons 2020 FET-OPEN grant 665158
Start Year 2011
 
Description Collaboration with Leeds NHS Teaching Hospital 
Organisation Leeds Teaching Hospitals NHS Trust
Country United Kingdom 
Sector Public 
PI Contribution Development of terahertz imaging system for skin diagnostics
Collaborator Contribution Provision of excised melanoma samples Histological analysis
Impact MRC Confidence in Concept grant MC_PC_14109
Start Year 2015
 
Description Collaboration with Ruhr-Universität Bochum 
Organisation Ruhr University Bochum
Country Germany 
Sector Academic/University 
PI Contribution This collaboration has made possible the study of injection-seeding of terahertz quantum cascade laser sources, and development of quantum cascade laser sources with hybrid-mode-section waveguides for improved outcoupling. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Expertise in experimental injection-seeding and coherent detection techniques; Access to experimental facilities including quantum cascade laser characterisation apparatus and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources; Intellectual input to research strategy.
Collaborator Contribution Contributions include: Expertise in injection-seeding of quantum cascade laser sources; Development of and access to high-resolution Fourier transform spectrometer and apparatus enabling cw injection-seeding of quantum cascade laser sources; Training of visiting research staff in experimental techniques for injection-seeding of quantum cascade laser sources; Intellectual input to research strategy.
Impact 10.1007/s10762-015-0239-4 10.1063/1.4896032
Start Year 2013
 
Description Collaboration with Rutheford Appleton Laboratory 
Organisation Rutherford Appleton Laboratory
Country United Kingdom 
Sector Public 
PI Contribution This research collaboration has enabled the development of Low Cost Upper Atmospheric Sounder (LOCUS) technology for future in-orbit demonstration. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources and coherent detection schemes; Access to experimental facilities including MBE growth facility and quantum cascade laser characterisation apparatus; Development, characterisation and provision of high-performance quantum cascade laser sources; Intellectual input to research strategy.
Collaborator Contribution Contributions include: Expertise in the development and fabrication of Schottky mixer and high-frequency waveguide technologies; Access to precision micromachining technology; Intellectual input to research strategy.
Impact 10.1049/el.2015.1137 European Space Agency grant 'Supra-THz Receiver Front-End Development' European Space Agency grant 'Modelling and Measurement of the THz Fingerprint Spectra of Biomolecules' 4000109286/13/NL/MV
Start Year 2013
 
Description Collaboration with School of Information Technology and Electrical Engineering, The University of Queensland, Australia 
Organisation University of Queensland
Country Australia 
Sector Academic/University 
PI Contribution This collaboration has been central to the on-going development of coherent sensing approaches based on the self-mixing effect in terahertz frequency quantum cascade lasers. My contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources, imaging systems and self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources; Training of visiting research staff in the experimental operation of terahertz quantum cascade laser sources and imaging systems; Intellectual input to research strategy.
Collaborator Contribution Contributions include: Expertise in experimental and theoretical aspects of self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems and mechanical fabrication facilities; Development and provision of custom-designed electronics components; Development of data analysis algorithms and software; Intellectual input to research strategy.
Impact Further funding: Cancer Research UK Leeds Centre Development Fund C37059/A16369 Australian Research Council Discovery Project DP120103703 Australian Research Council Discovery Project DP160103910 PhD studentship, funded by University of Leeds DTA award MRC Confidence in Concept grant MC_PC_14109 EPSRC Impact Acceleration Account award EP/K503836/1 European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016 Publications: 10.1109/JSEN.2012.2218594 10.1364/OE.21.022194 10.1063/1.4827886 10.1063/1.4839535 10.1364/OL.39.002629 10.1364/OE.22.018633 10.1088/0022-3727/47/37/374008 10.1364/BOE.5.003981 10.1364/OL.40.000994 10.1063/1.4918993 10.1364/OL.40.000950 10.1049/el.2015.2878 10.1364/OE.24.021948 10.3390/s16030352 10.1364/OE.24.020554 10.1109/JSEN.2015.2507184 10.1109/JSTQE.2016.2638539 Organisation of, and participation in, The Training School in Terahertz, Infrared and Millimetre Wave technology and its Application to Sensing and Imaging Invited talk at Photonics West 2016 Invited talk at International Quantum Cascade Laser School and Workshop 2016
Start Year 2011
 
Description Collaboration with Teraview Ltd (UK) 
Organisation Teraview Ltd
Country United Kingdom 
Sector Private 
PI Contribution Expertise in experimental and theoretical aspects of quantum cascade laser sources, imaging systems and self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems, clean-room fabrication facilities and molecular beam epitaxial growth facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution TeraView Ltd (http://www.teraview.com), core business is focused on selling systems to the non-destructive testing, pharmaceutical, materials characterization and electronics markets. Trials are under way to assess the application of our laser based technology to industrial inspection of silicon wafers, of relevance to the semiconductor manufacturing industry.
Impact European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016
Start Year 2016
 
Description Collaboration with Univ. of Texas at Austin, USA 
Organisation University of Texas at Austin
Country United States 
Sector Academic/University 
PI Contribution This collaboration has made possible the development of photo-expansion nanospectroscopy techniques using terahertz quantum cascade laser sources. My contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution Contributions include: Expertise in photo-expansion nanospectroscopy techniques; Access to experimental facilities including photo-expansion nanospectroscopy system; Intellectual input to research strategy.
Impact 10.1117/12.2000743
Start Year 2011
 
Description Collaboration with University of Nottingham 
Organisation University of Nottingham
Country United Kingdom 
Sector Academic/University 
PI Contribution Expertise in pulsed terahertz generation and detection; Access to experimental facilities including terahertz spectroscopy systems, clean-room fabrication facilities, and MBE growth facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution Expertise in acoustic wave generation
Impact EPSRC grant EP/M01598X/1
Start Year 2015
 
Description Participation in BMBS COST Action BM1205, European Network for Skin Cancer Detection using Laser Imaging 
Organisation European Cooperation in Science and Technology (COST)
Department European Network for Skin Cancer Detection using Laser Imaging
Country United Kingdom 
Sector Public 
PI Contribution This network provides an interdisciplinary framework to enhance interaction activities within the field of optical biosensing, between world-class academic groups, labs and system integrators from industry. It exploits novel laser sources and innovative feedback interferometry in specific biomedical applications. This group provides an ideal platform for interaction activities with international academic and industrial partners relevant to the development of coherent imaging systems at The University of Leeds. My contributions include: Hosting Short-term Scientific Missions (STSMs) aimed at early-career researchers from across Europe; Management Committee role; Leader of 'Terahertz imaging' work group. Organisation of 'Training School in Terahertz, Infrared and Millimetre Wave technology and its Application to Sensing and Imaging', hosted at Leeds (2014).
Collaborator Contribution This network provides an interdisciplinary framework to enhance interaction activities within the field of optical biosensing, between world-class academic groups, labs and system integrators from industry. It exploits novel laser sources and innovative feedback interferometry in specific biomedical applications. This group provides an ideal platform for interaction activities with international academic and industrial partners relevant to the development of coherent imaging systems at University of Leeds.
Impact This network is multi-disciplinary, involving academics and industrial partners from across the physical sciences (Physics, Engineering) as well as medical researchers and practicioners. Outcomes include: Invited talk at 'The International Conference on THz and Mid Infrared Radiation and Applications to Cancer Detection Using Laser Imaging', 2013; Organisation of 'Training School in Terahertz, Infrared and Millimetre Wave technology and its Application on Sensing and Imaging' 2014; Participation in 'Interdisciplinary workshop on Laser Imaging for Skin Cancer detection'; Participation in various multi-disciplinary Working Groups. Publications: 10.1364/BOE.5.003981 Further funding: Australian Research Council (ARC): DP160103910 - Australian Research Council Discovery Project (A$ 390000; 2016 - 2018) Medical Research Council (MRC): MC_PC_14109 - MRC Confidence in Concept grant (£ 75000; 2015) Cancer Research UK Leeds Centre: C37059/A16369 - Cancer Research UK Leeds Centre Development Fund (£ 10000; 2013)
Start Year 2012
 
Description Participation in Coherent Terahertz Systems (COTS) EPSRC Programme Grant 
Organisation University College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Among the aims of this partnership are: The creation of the integrated phase-locked optical synthesis technologies that underpin coherent signal generation across the THz spectrum; The development of phase-locked electronically tuneable quantum cascade laser (QCL) technology; The development of InGaAs/InP photoconductive mixers using iron doping or novel ion implantation processes; The development of systems exploiting the THz spectrum for applications areas including coherent imaging and sensing systems. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources, imaging systems and self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems, clean-room fabrication facilities, and photomixer characterisation apparatus; Development, characterisation and provision of high-performance quantum cascade laser sources; Expertise in experimental aspects of InGaAs/InP photoconductive mixer technology; Development of coherent systems based on photomixer technology; Development of phase-locked electronically tuneable quantum cascade laser (QCL) technology.
Collaborator Contribution ...
Impact Publications: 10.1364/OE.22.016595 10.1364/OE.21.022988 10.1063/1.4942452 10.1063/1.4943088 10.1063/1.4946845 10.1364/OE.25.000486 Invited talk at Photonics West 2016 Invited talk at International Quantum Cascade Laser School and Workshop 2016 Further funding: European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016
Start Year 2012
 
Description Participation in Coherent Terahertz Systems (COTS) EPSRC Programme Grant 
Organisation University of Cambridge
Country United Kingdom 
Sector Academic/University 
PI Contribution Among the aims of this partnership are: The creation of the integrated phase-locked optical synthesis technologies that underpin coherent signal generation across the THz spectrum; The development of phase-locked electronically tuneable quantum cascade laser (QCL) technology; The development of InGaAs/InP photoconductive mixers using iron doping or novel ion implantation processes; The development of systems exploiting the THz spectrum for applications areas including coherent imaging and sensing systems. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources, imaging systems and self-mixing sensing approaches; Access to experimental facilities including terahertz imaging systems, clean-room fabrication facilities, and photomixer characterisation apparatus; Development, characterisation and provision of high-performance quantum cascade laser sources; Expertise in experimental aspects of InGaAs/InP photoconductive mixer technology; Development of coherent systems based on photomixer technology; Development of phase-locked electronically tuneable quantum cascade laser (QCL) technology.
Collaborator Contribution ...
Impact Publications: 10.1364/OE.22.016595 10.1364/OE.21.022988 10.1063/1.4942452 10.1063/1.4943088 10.1063/1.4946845 10.1364/OE.25.000486 Invited talk at Photonics West 2016 Invited talk at International Quantum Cascade Laser School and Workshop 2016 Further funding: European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016
Start Year 2012
 
Description Participation in Horizons2020 FET-OPEN project 'ULTRAQCL' 
Organisation National Center for Scientific Research (Centre National de la Recherche Scientifique CNRS)
Country France 
Sector Public 
PI Contribution Among the aims of this partnership are the development of mode-locked terahertz quantum cascade laser (QCL) technology for short pulse generation, wideband frequency comb generation, frequency comb spectroscopy, and quantum control experiments. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Expertise in experimental and theoretical aspects of mode-locking of quantum cascade lasers, and self-induced transparency effects. Access to experimental facilities including terahertz quantum cascade laser characterisation apparatus, injection seeding apparatus, MBE wafer growth, and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution ...
Impact Further funding: European Commission (EC): 703912 - European Commission Horizon 2020 Marie Sklodowska-Curie Fellowship programme H2020-MSCA-IF-2015
Start Year 2015
 
Description Participation in Horizons2020 FET-OPEN project 'ULTRAQCL' 
Organisation University Paris Sud
Country France 
Sector Academic/University 
PI Contribution Among the aims of this partnership are the development of mode-locked terahertz quantum cascade laser (QCL) technology for short pulse generation, wideband frequency comb generation, frequency comb spectroscopy, and quantum control experiments. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Expertise in experimental and theoretical aspects of mode-locking of quantum cascade lasers, and self-induced transparency effects. Access to experimental facilities including terahertz quantum cascade laser characterisation apparatus, injection seeding apparatus, MBE wafer growth, and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution ...
Impact Further funding: European Commission (EC): 703912 - European Commission Horizon 2020 Marie Sklodowska-Curie Fellowship programme H2020-MSCA-IF-2015
Start Year 2015
 
Description Participation in Horizons2020 FET-OPEN project 'ULTRAQCL' 
Organisation University of Bari
Country Italy 
Sector Academic/University 
PI Contribution Among the aims of this partnership are the development of mode-locked terahertz quantum cascade laser (QCL) technology for short pulse generation, wideband frequency comb generation, frequency comb spectroscopy, and quantum control experiments. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Expertise in experimental and theoretical aspects of mode-locking of quantum cascade lasers, and self-induced transparency effects. Access to experimental facilities including terahertz quantum cascade laser characterisation apparatus, injection seeding apparatus, MBE wafer growth, and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution ...
Impact Further funding: European Commission (EC): 703912 - European Commission Horizon 2020 Marie Sklodowska-Curie Fellowship programme H2020-MSCA-IF-2015
Start Year 2015
 
Description Participation in Horizons2020 FET-OPEN project 'ULTRAQCL' 
Organisation University of Regensburg
Country Germany 
Sector Academic/University 
PI Contribution Among the aims of this partnership are the development of mode-locked terahertz quantum cascade laser (QCL) technology for short pulse generation, wideband frequency comb generation, frequency comb spectroscopy, and quantum control experiments. Specific contributions include: Expertise in experimental and theoretical aspects of quantum cascade laser sources; Expertise in experimental and theoretical aspects of mode-locking of quantum cascade lasers, and self-induced transparency effects. Access to experimental facilities including terahertz quantum cascade laser characterisation apparatus, injection seeding apparatus, MBE wafer growth, and clean-room fabrication facilities; Development, characterisation and provision of high-performance quantum cascade laser sources;
Collaborator Contribution ...
Impact Further funding: European Commission (EC): 703912 - European Commission Horizon 2020 Marie Sklodowska-Curie Fellowship programme H2020-MSCA-IF-2015
Start Year 2015
 
Title A Laser System for Imaging and Materials Analysis 
Description This patent covers the novel technology developed within this grant for non-invasive materials analysis using the self-mixing effect in lasers. 
IP Reference WO2015024058 
Protection Patent granted
Year Protection Granted 2013
Licensed No
Impact This patent led to further funding to explore commercialisation of this technology: 1) EPSRC Impact Acceleration Account award EP/K503836/1 (2015) 2) European Commission (EC): 727541 - European Commission Proof-of-Concept grant award ERC-PoC-2016 (€ 150000; 2016 - 2017) This patent has also led directly to 2 industrial collaborations: 1) 'L3 Micreo Ltd', who will undertake the specific construction of a compact laser head using our THz QCL technology. This will raise the technological readiness level (TRL) of our imaging technology, and increase the opportunity for commercial uptake. A Memorandum of Understanding has been agreed between the University of Leeds, UniQuest and Micreo reflecting the commercialization opportunity. 2) TeraView Ltd (http://www.teraview.com), whose core business is focused on selling systems to the non-destructive testing, pharmaceutical, materials characterization and electronics markets. Trials are under way to assess the application of our technology to industrial inspection of silicon wafers, of relevance to the semiconductor manufacturing industry.
 
Title Two Photon Emitting Terahertz QCL 
Description A Two Photon Emitting Terahertz QCL 
IP Reference GB1814766.0 
Protection Patent application published
Year Protection Granted 2018
Licensed No
Impact None
 
Description Article in Physics World Magazine, June 2016 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Article featuring my research published in Physics World Magazine, June 2016.
This has led to greater understanding of terahertz technology by the general public and other academic researchers.
Year(s) Of Engagement Activity 2016
URL http://physicsworld.com/
 
Description Early Career Researcher Engineering Showcase at The Royal Academy of Engineering Regional Lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Supporters
Results and Impact The Early Career Researcher Engineering Showcase formed part of the Royal Academy of Engineering Regional Lecture in 2012. The Regional Lecture is an annual public lecture for northern universities and takes the form of a topic of broad interest. It is an opportunity for academic staff and younger researchers to disseminate their research and discuss potential societal benefits with the public. My presentation prompted numerous questions and discussions.

The public were impressed by the breadth and applicability of research undertaken at The University of Leeds.
Year(s) Of Engagement Activity 2012
URL http://www.raeng.org.uk/events/list-of-events/2012/march/the-royal-academy-of-engineering-regional-l...
 
Description Hands-on demonstration/workshop at Royal Microscopy Meeting, RMS SPM Meeting 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This hands-on activity/workshop was organised as part of the Royal Microscopy Society RMS SPM Meeting held in Leeds, 25-26th June 2018.
12 postgraduate researchers and PhD students visited the Research Laboratories in the School of Electronic and Electrical Engineering at the University of Leeds, and were provided with a demonstration of the University's Terahertz Microscopy system. This sparked questions and discussion afterwards.
Year(s) Of Engagement Activity 2018
 
Description Interdisciplinary workshop on Laser Imaging for Skin Cancer detection 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Health professionals
Results and Impact This workshop/discussion group provided an interdisciplinary framework to enhance interaction activities within the field of optical biosensing, between world-class academic groups and medical practicioners and researchers.

This workshop resulted in lively two-way discussion between academic researchers and clinical practicioners, leading to better understanding of end-user needs and technological challenges.
Year(s) Of Engagement Activity 2014
 
Description Media interest in laser developments 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The development of the world's first terahertz quantum cascade laser emitting more than 1W of power was reported in more than a dozen news outlets world-wide including the BBC website, BBC Radio Leeds, The Times of India (national newspaper) and websites including www.phys.org.

This media interest generated publicity and interest in my research and other research taking place at The University of Leeds, as well as improving the public's understanding and appreciation of science.
Year(s) Of Engagement Activity 2014
URL http://phys.org/news/2014-02-world-powerful-terahertz-laser-chip.html
 
Description Organisation of, and participation in, The International Quantum Cascade Laser School and Workshop, 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This workshop aimed to bring together researchers from across the field of terahertz science. The workshop also served as a training school for PhD students, postdoctoral researchers and early career researchers from across Europe.
Year(s) Of Engagement Activity 2016
 
Description Organisation of, and participation in, The Training School in Terahertz, Infrared and Millimetre Wave technology and its Application to Sensing and Imaging 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation workshop facilitator
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This workshop aimed to bring together researchers from across the fields of terahertz, infrared and millimetre wave technologies in order to foster collaborations and discussion of how to open up the these fields to widespread scientific and commercial applications in imaging and sensing. The workshop also served as a training school for PhD students and early career researchers from across Europe. Part of this activity involved a laboratory demonstration session, coordinated by myself and aimed at early-career researchers, which attracted much interest and stimulated discussion and sharing of ideas.

...
Year(s) Of Engagement Activity 2014
URL http://skin-laser-imaging.org/events-2/bm1205-and-mp1204-cost-actions-training-school/
 
Description School of Electronic and Electrical Engineering Open Days, University of Leeds 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The research activity undertaken as part of this award, and its potential for societal benefit, was presented to 6th form (college) students and their parents/guardians at The School of Electronic and Electrical Engineering Open Days at The University of Leeds. This included laboratory demonstrations and prompted numerous questions and discussions afterwards.

Feedback indicated that participants gained a better understanding of the potential impact/societal benefits of my research, as well as being motivated to study engineering/physics at University.
Year(s) Of Engagement Activity 2011,2012,2013
 
Description The Innovative Research Call in Explosives and Weapons Detection Showcase, London 2011 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The aim of this showcase was to enable the further progression of research by appropriate investment or collaboration. This was an opportunity for representatives from Government, academia, investment groups and industry to come together and identify potential ways in which the outputs from research projects could be exploited and applied.
Participation in this showcase event provided the opportunity to present my research to Government, academia, investment groups and industry.

Further funding opportunities were brought to my attention.
Year(s) Of Engagement Activity 2011
URL https://www.adsgroup.org.uk/articles/26422
 
Description UK Terahertz Day, Cavendish Laboratory, Cambridge, July 2013 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation poster presentation
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Showcase poster at UK TERAHERTZ DAY.

The UK Terahertz Day was a UK THz community discussion event organised as part of The EPSRC Coherent TeraHertz Systems (COTS) Programme Grant. The event provided an opportunity to introduce my research to other academic and industrial groups.

...
Year(s) Of Engagement Activity 2013
URL http://www.ee.ucl.ac.uk/research/eventukterahertzday