COherent Terahertz Systems (COTS)-opening up the terahertz spectrum for widespread application
Lead Research Organisation:
University College London
Department Name: Electronic and Electrical Engineering
Abstract
The terahertz (THz) frequency region within the electromagnetic spectrum, covers a frequency range of about one hundred times that currently occupied by all radio, television, cellular radio, Wi-Fi, radar and other users and has proven and potential applications ranging from molecular spectroscopy through to communications, high resolution imaging (e.g. in the medical and pharmaceutical sectors) and security screening. Yet, the underpinning technology for the generation and detection of radiation in this spectral range remains severely limited, being based principally on Ti:sapphire (femtosecond) pulsed laser and photoconductive detector technology, the THz equivalent of the spark transmitter and coherer receiver for radio signals. The THz frequency range therefore does not benefit from the coherent techniques routinely used at microwave/optical frequencies. Our programme grant will address this. We have recently demonstrated optical communications technology-based techniques for the generation of high spectral purity continuous wave THz signals at UCL, together with state-of-the-art THz quantum cascade laser (QCL) technology at Cambridge/Leeds. We will bring together these internationally-leading researchers to create coherent systems across the entire THz spectrum. These will be exploited both for fundamental science (e.g. the study of nanostructured and mesoscopic electron systems) and for applications including short-range high-data-rate wireless communications, information processing, materials detection and high resolution imaging in three dimensions.
Planned Impact
The proposed work is focused on the goal of enabling the THz part of the electromagnetic spectrum to be accessed with the same precision that can be achieved at radio and, increasingly, optical frequencies. We envisage that this will enable important scientific, commercial and societal benefits.
Considering scientific benefits, the development of coherent THz spectroscopy using simple source/detector modules will have great impact in many areas of research. For example, many more 'labels', including low lying vibrational states as well as spin states split by larger fields, will be useable for determining the structural and dynamical parameters of proteins. On the physical sciences side, using coherent THz radiation will allow measurement and manipulation, including the creation of coherent superpositions, of quantum states (in e.g. single electron transistors) separated by energies of order tens of Kelvin, implying much less stringent cooling requirements than demanded currently for microwave-based state manipulation. This capability would be valuable for quantum information processing research. We are already involved in collaborations with museums and galleries, where the capability of THz imaging to study underlying layer structure in paintings and glazes has revealed details of considerable historical interest.
Concerning commercial benefits, the work on ultra-wideband wireless would enable the creation of wireless devices having similar information transfer rates to those available from direct fibre connections. This represents a significant (> $1b based on conventional system sales) [Infonetics] market opportunity. The work on spectroscopy and sensing will enable the production of small footprint (lab bench-based) CW microwave-->THz spectrometers for routine analysis needs in clinical labs and in pharmaceutical production, as well as stand-off detection sytems for use in security applications. Finally, the new coherent imaging capabilities envisaged will be of value in areas from security scanning to clinical imaging of cancerous tissue to determine surgical margins. These are again expected to be large (> $0.5b, with 37% annual growth rate by 2018 [BCC Research]) markets.
Concerning societal benefits, we anticipate that the population will welcome the availability of much increased data rates from their wireless devices and the increasing interactivity that will result. There has been considerable concern about radiation exposure from whole body X-ray security scanners and the use of THz scanners with their benefit of non-ionizing radiation will, we consider, be welcomed. Societal benefits through better security and crime detection using THz sensing and spectroscopy, will also accrue. Improvements to healthcare through compact tools for clinical imaging and pharmaceutical testing will constitute further societal benefits. Finally, we see cultural benefits through work using THz imaging to learn more about the creation of works of art.
In order to ensure that these benefits will be realised we have set up a range of partnerships with key industries and users, to contribute their knowledge of applications requirements and to provide exploitation routes for the technologies developed. As well as traditional knowledge transfer routes, such as demonstrators, publication, spin-outs and IP licensing we expect that transfer through the provision of highly trained researchers from the Programme to beneficiaries will be a major feature of our work.
We anticipate that the benefits outlined above will be achieved within five years of the completion of this grant.
In addition to the beneficiaries identified above, the knowledge gained through the project is likely to enable us to engage with businesses operating in related areas through collaboration or consultancy. Here, the role of project partner BNC is of special importance.
Considering scientific benefits, the development of coherent THz spectroscopy using simple source/detector modules will have great impact in many areas of research. For example, many more 'labels', including low lying vibrational states as well as spin states split by larger fields, will be useable for determining the structural and dynamical parameters of proteins. On the physical sciences side, using coherent THz radiation will allow measurement and manipulation, including the creation of coherent superpositions, of quantum states (in e.g. single electron transistors) separated by energies of order tens of Kelvin, implying much less stringent cooling requirements than demanded currently for microwave-based state manipulation. This capability would be valuable for quantum information processing research. We are already involved in collaborations with museums and galleries, where the capability of THz imaging to study underlying layer structure in paintings and glazes has revealed details of considerable historical interest.
Concerning commercial benefits, the work on ultra-wideband wireless would enable the creation of wireless devices having similar information transfer rates to those available from direct fibre connections. This represents a significant (> $1b based on conventional system sales) [Infonetics] market opportunity. The work on spectroscopy and sensing will enable the production of small footprint (lab bench-based) CW microwave-->THz spectrometers for routine analysis needs in clinical labs and in pharmaceutical production, as well as stand-off detection sytems for use in security applications. Finally, the new coherent imaging capabilities envisaged will be of value in areas from security scanning to clinical imaging of cancerous tissue to determine surgical margins. These are again expected to be large (> $0.5b, with 37% annual growth rate by 2018 [BCC Research]) markets.
Concerning societal benefits, we anticipate that the population will welcome the availability of much increased data rates from their wireless devices and the increasing interactivity that will result. There has been considerable concern about radiation exposure from whole body X-ray security scanners and the use of THz scanners with their benefit of non-ionizing radiation will, we consider, be welcomed. Societal benefits through better security and crime detection using THz sensing and spectroscopy, will also accrue. Improvements to healthcare through compact tools for clinical imaging and pharmaceutical testing will constitute further societal benefits. Finally, we see cultural benefits through work using THz imaging to learn more about the creation of works of art.
In order to ensure that these benefits will be realised we have set up a range of partnerships with key industries and users, to contribute their knowledge of applications requirements and to provide exploitation routes for the technologies developed. As well as traditional knowledge transfer routes, such as demonstrators, publication, spin-outs and IP licensing we expect that transfer through the provision of highly trained researchers from the Programme to beneficiaries will be a major feature of our work.
We anticipate that the benefits outlined above will be achieved within five years of the completion of this grant.
In addition to the beneficiaries identified above, the knowledge gained through the project is likely to enable us to engage with businesses operating in related areas through collaboration or consultancy. Here, the role of project partner BNC is of special importance.
Organisations
- University College London (Lead Research Organisation)
- National Physical Laboratory (Collaboration)
- Rutherford Appleton Laboratory (Collaboration)
- European Space Agency (Collaboration)
- City University of Hong Kong (Collaboration)
- Home Office (Project Partner)
- TeraView (United Kingdom) (Project Partner)
- L3Harris (United Kingdom) (Project Partner)
- Aerospace and Defence KTN (Project Partner)
- University of Cambridge (Project Partner)
- Airbus (United Kingdom) (Project Partner)
- National Institute of Information and Communications Technology (Project Partner)
- Chemring Technology Solutions (United Kingdom) (Project Partner)
- Rutgers, The State University of New Jersey (Project Partner)
- Agilent Technologies (United States) (Project Partner)
- Bio Nano Consulting (Project Partner)
- Smiths Group (United Kingdom) (Project Partner)
- IBM Research - Almaden (Project Partner)
- University of Kassel (Project Partner)
- III V Lab (Project Partner)
Publications
Carpintero G.
(2014)
Fully monolithic photonic integrated circuits for microwave and millimeter wave signal generation
in Progress in Electromagnetics Research Symposium
Carpintero Guillermo
(2015)
Semiconductor TeraHertz Technology: Devices and Systems at Room Temperature Operation
Castellano F
(2015)
Distributed feedback terahertz frequency quantum cascade lasers with dual periodicity gratings
in Applied Physics Letters
Castellano F
(2015)
THz waveguide adapters for efficient radiation out-coupling from double metal THz QCLs.
in Optics express
Cavalié P
(2013)
High order sideband generation in terahertz quantum cascade lasers
in Applied Physics Letters
Chakraborty S
(2012)
Discrete mode tuning in terahertz quantum cascade lasers.
in Optics express
Chakraborty S
(2012)
Digital phase control in a Y-coupled plasmonic terahertz laser system
Description | We have demonstrated that THz frequencies are suitable for high data rate, short range wireless communications. In particular, we have shown by systems analysis and confirmed experimentally that atmospheric attenuation levels are acceptable for indoor wireless coverage systems. We have made a proof of principle demonstration of THz spectroscopy with unprecedented resolution and frequency accuracy. At the start of the COTS Programme Grant, highly coherent (Hz linewidth) continuous wave THz sources did not exist. We started from heterodyning of phase-locked communications wavelength lasers in ultra-fast photodiodes to access the frequency range up to 2 THz. Higher frequencies were addressed using quantum cascade laser (QCL) technology. A selection of achievements of the COTS Programme Grant include: • Development of QCL self-mixing with the University of Queensland [1] [2] leading to new IP filings. • Successful demonstration of photonically generated THz wireless signals at up to 100 Gb/s [3] [4], leading to an invited tutorial presentation at the 2014 IEEE/OSA Optical Fibre Communications Conference and an invited review in Nature Photonics [5]. • Successful demonstration of the first monolithically integrated dual DFB laser source and UTC device, with up to 100 µW generated at 120 GHz (through an international collaboration with III-V Laboratories) [6]. • Successful demonstration of the first locking of a THz QCL operating at 1.997 THz to a fibre-based comb source [Optics Letters, in preparation]. • Successful demonstration of coupled cavity Vernier effect tuned QCL [7]. • First demonstration of efficient out-coupling of QCL mode using hollow waveguide technology [8] [9]. A full publication list (> 250 papers and other information can be found on the COTS website www.terahertzsystems.org. Added Value and use of Programme Grant Flexibility Collaboration between the COTS consortium has enabled unique technologies to be developed, which could not have been developed otherwise. For example, the locked QCL capability was achieved using University of Leeds QCL with UCL photonic locking technology. The same technology was used to demonstrate ultra narrow linewidth spectroscopy capability using baseline FTIR measurements from University of Leeds and London Centre for Nanotechnology. Achieving these results required deployment of personnel and equipment resources between the consortium universities in a flexible manner. A further example is the use of UCL low-loss THz waveguide designs fabricated at the University of Cambridge and by international project partner Rutgers University to achieve coupling to samples in cryostatic environments. The COTS Programme Grant has also played a key role in the formulation of the successful UK THz Network proposal TeraNet (PI: Professor J. E. Cunningham) funded by EPSRC, and has led engagement with industrial and other end users through such activities as the successful THz Day, held at Cambridge University. Further, we have developed a set of outreach activities from exhibition at the science museum (Dr C. Renaud and Dr M. Fice) on the 19th of June 2014 in collaboration with the Photonics KTN and the Institute of Physics or a BBC radio broadcast explaining the use of QCL for THz techonology given by Professors E. Linfield and G Davies. COTS (Dr Fice) also presented an exhibition at the Big Bang Science Fair at Alexandra Palace. Finally in order to disseminate even further the importance of the THz part of the spectrum and developing technologies to access it a video was edited and published on youtube (https://www.youtube.com/watch?v=7FY5kbvBbic) [1] P. Dean and al., Applied Physics Letters, vol. 103, p. 181112, 2013. [2] A. Rakic and al., Optics Express, vol. 21, pp. 22194-22205, 2013. [3] H. Shams and al., IEEE Photonics Journal, vol. 7, 2015. [4] H. Shams and al., Optics Express, vol. 22, pp. 23465-123472, 2014. [5] T. Nagatsuma, G. Ducournau and C. C. Renaud, Nature Photonics, vol. 10, pp. 371-379, 2016. [6] F. Van Dijk and al., IEEE Photonics Technology Letters, vol. 26, pp. 965-968, 2014. [7] I. Kundu and al., Optics Express, vol. 22, p. 16595-16605, 2014. [8] F. Castellano and al., Optics Express, vol. 23, p. 5190-5200, 2015. [9] R. Wallis and al., Optics Express, vol. 23, p. 26276-87, 2015. |
Exploitation Route | Short range wireless systems could be developed for high capacity connections between personal devices, such as smart-phones, tablets and lap-top computers and the fixed communications infrastructure. Precision THz spectroscopy can be used for the analysis of molecular structure in substances of commercial interest. A new Programme Grant HyperTHz commenced in 2017 to develop THz instrumentation based upon COTS technologies. |
Sectors | Aerospace Defence and Marine Chemicals Digital/Communication/Information Technologies (including Software) Electronics Healthcare Government Democracy and Justice Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology Security and Diplomacy |
URL | http://www.terahertzsystems.org |
Description | Demonstrations of high data rate wireless transmission carried out under this grant have increased interest in the use of THz frequencies for future wireless systems. The technology is now under active investigation by companies worldwide for use in 5G+ communications systems for low-latency data-centre interconnects and for intersatellite links. The research led to a European collaborative project TERAPOD in which UCL and Dell demonstrated a THz data-centre interconnect. The THz generation materials developed within the programme are supplied commercially to a major manufacturer of THz products. A patent, granted in 2015, relating to a high speed switch based on materials developed in the programme, has been assigned to a major international electronics company. A patent on THz bandwidth photodiodes using the technologies developed in the programme has been granted in the US and Japan. The technology developed is now being used by two manufacturers. A joint patent with the University of Queensland on a laser system for imaging and materials analysis has now been granted in numerous territories including America, Europe, China and Australia. Our collaborators at Queensland are working with clinical partners at Princess Alexandra Hospital with the aim of establishing a clinical trial to investigate the use of the technology for screening of skin cancers. THz communications now features in international standardisation discussions, eg IEEE 802.15 and this frequency range is now the subject of international frequency allocation discussions at World Administrative Radio Conferences. |
First Year Of Impact | 2018 |
Sector | Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy |
Impact Types | Societal Economic Policy & public services |
Description | (TERAOPTICS) - Terahertz Photonics for Communications, Space, Security, Radio-Astronomy, and Material Science |
Amount | € 3,974,527 (EUR) |
Funding ID | 956857 |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 08/2020 |
End | 08/2024 |
Description | CDT Studentship |
Amount | £75,000 (GBP) |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2017 |
End | 09/2020 |
Description | Collaborative Inpact studentship with National Physical Laboratory |
Amount | £100,000 (GBP) |
Organisation | University College London |
Sector | Academic/University |
Country | United Kingdom |
Start | 11/2014 |
End | 10/2018 |
Description | ESA Call on Millimeter wave high power source |
Amount | € 385,000 (EUR) |
Funding ID | 4000117914/16/NL/GLC |
Organisation | European Space Agency |
Department | European Space Research and Technology Centre (ESTEC) |
Sector | Public |
Country | Netherlands |
Start | 01/2017 |
End | 12/2019 |
Description | FP7-ICT IPHOBAC-NG |
Amount | € 480,000 (EUR) |
Funding ID | 619870 |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 11/2013 |
End | 10/2016 |
Description | Horizon 2020 |
Amount | € 3,704,800 (EUR) |
Funding ID | 761579 |
Organisation | European Commission H2020 |
Sector | Public |
Country | Belgium |
Start | 08/2017 |
End | 08/2020 |
Description | Optically controlled THz phased array antennas |
Amount | £1,178,040 (GBP) |
Funding ID | EP/R042578/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 08/2018 |
End | 06/2022 |
Description | PATTERN: Next generation ultra-high-speed microwave Photonic integrATed circuiTs using advancE hybRid iNtegration |
Amount | £589,667 (GBP) |
Funding ID | 10044974 |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 08/2022 |
End | 08/2026 |
Description | Programme Grant |
Amount | £6,517,861 (GBP) |
Funding ID | EP/P021859/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 05/2017 |
End | 05/2022 |
Title | Data associated with 'Frequency tunability and spectral control in terahertz quantum cascade lasers with phase-adjusted finite-defect-site photonic lattices' |
Description | This dataset contains experimental data presented in the paper titled 'Frequency tunability and spectral control in terahertz quantum cascade lasers with phase-adjusted finite-defect-site photonic lattices'. The effect of finite-defect-site photonic lattices (PLs) on the spectral emission of terahertz (THz) frequency quantum cascade lasers (QCLs), is studied both theoretically and experimentally. A central p-phase adjusted defect is incorporated into the PL to slectively favor emission within the photonic bandgap. The effect of the PL duty cycle and the longitudinal position of such PLs relative the QCL cavity is also investigated, and is used to demonstrate three distinct spectral behaviors: single mode emission from QCLs in the range 2.2-5 THz, with a side-mode suppression ratio of 40 dB and exhibiting continuous frequency tuning over >8 GHz; discrete tuning between two engineered emission modes separated by ~40 GHz; and multiple-mode emission with an engineered logitudinal frequency spacing between the emission lines. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
URL | http://archive.researchdata.leeds.ac.uk/157/ |
Title | Data associated with 'Gas spectroscopy through multimode self-mixing in a double-metal terahertz quantum cascade laser' |
Description | We demonstrate a broadband terahertz gas spectroscopy through multimode self-mixing in a quantum cascade laser. The transmission spectra of methanol were simultaneously obtained within two distinct frequency ranges from 3.359 THz to 3.369 THz and from 3.426 THz to 3.433 THz. This approach has increased the total measurement bandwidth of self-mixing spectroscopy to 17GHz, by a factor of ~7, and underpins future work to develop the first broadband "detector-free" multi-gas QCL spectroscopy systems. Figure 1 shows schematic illustration of the configuration of the gas spectroscopy system. Figure 2 and figure 3 are the characterisation of emission spectra and the frequency tuning range of the QCL. Figures 4 and figure 5 shows the spectra of the methanol, obtained simultaneously from the two modes of the QCL. Figure 6 shows the absorption coefficients of the methanol at different pressure. |
Type Of Material | Database/Collection of data |
Year Produced | 2018 |
Provided To Others? | Yes |
Title | Dataset associated with 'Broadband heterogeneous THz quantum cascade laser based on LO-phonon-assisted interminiband transitions' |
Description | This archive contains the dataset associated with the publication entitled ' Broadband heterogeneous THz quantum cascade laser based on LO-phonon-assisted interminiband transitions'. We demonstrate broadband heterogeneous THz quantum cascade laser by exploiting an active region design employing longitudinal optical (LO)-phonon-assisted interminiband transitions. Continuous wave laser emission with a threshold current density of ~120 A/cm2, a dynamic range of ~3.1, and a spectrum emission spanning from 2.4 to 3.4 THz at 15 K is demonstrated. |
Type Of Material | Database/Collection of data |
Year Produced | 2018 |
Provided To Others? | Yes |
Title | Dataset associated with 'Ultrafast switch-on dynamics of frequency tuneable semiconductor lasers' |
Description | This dataset contains experimental data presented in the paper titled 'Ultrafast switch-on dynamics of frequency tuneable semiconductor lasers'. Single-mode frequency-tuneable semiconductor lasers based on monolithic integration of multiple cavity sections are important components, widely used in optical communications, photonic integrated circuits, and other optical technologies. To date, investigations of the ultrafast switching processes in such lasers, essential to reduce frequency cross-talk, have been restricted to the observation of intensity switching over nanosecond-timescales. Here, we report coherent measurements of the ultrafast switch-on dynamics, mode competition and frequency selection in a monolithic frequency-tuneable laser using coherent time-domain sampling of the laser emission. This approach allows us to observe hopping between lasing modes on picosecond-timescales and the temporal evolution of transient multi-mode emission into steady-state single mode emission. The underlying physics is explained through a full multi-mode, temperature dependent carrier and photon transport model. Our results show that the fundamental limit on the timescales of frequency-switching between competing modes varies with the underlying Vernier alignment of the laser cavity. |
Type Of Material | Database/Collection of data |
Year Produced | 2018 |
Provided To Others? | Yes |
Title | Dataset associated with Injection locking of a terahertz quantum cascade laser to a telecommunications wavelength frequency comb. |
Description | This archive contains the dataset associated with the publication entitled Injection locking of a terahertz quantum cascade laser to a telecommunications wavelength frequency comb. In this work we injection lock a QCL operating at 2 THz to a compact fibre-based telecommunications wavelength frequency comb, where the comb line spacing is referenced to a microwave frequency reference. This results in the QCL frequency locking to an integer harmonic of the microwave reference, and the QCL linewidth reducing to the multiplied linewidth of the microwave reference, < 100 Hz. Furthermore, we perform phase-resolved detection of the locked QCL and measure the phase noise of the locked system to be -75 dBc/Hz at 10 kHz offset from 2 THz carrier. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
URL | http://archive.researchdata.leeds.ac.uk/232/ |
Title | Dataset for Gas spectroscopy with integrated frequency monitoring through self-mixing in a terahertz quantum-cascade laser. |
Description | This archive contains the dataset associated with the publication entitled 'Gas spectroscopy with integrated frequency-monitoring through self-mixing in a terahertz quantum-cascade laser';. In this work, we demonstrate a gas spectroscopy technique based on self-mixing interferometry in a 3.4-THz quantum-cascade laser (QCL). All previous QCL spectroscopy techniques have required additional THz instrumentation (detectors, mixers or spectrometers) for system-precalibration or in situ spectral analysis. By contrast, our system self-calibrates the laser frequency to a precision of 630 MHz (0.02%) by analyzing voltage perturbations across the QCL, in response to optical feedback from a mirror mounted on a 0-800-mm round-trip delayline. We demonstrate spectroscopy of methanol by introducing a gas cell into the feedback path, and show that a limiting absorption coefficient of ~0.0001 /cm is resolvable. This dataset includes the raw data used to generate all figures within the publication. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
Title | Research data supporting "Efficient coupling of double-metal terahertz quantum cascade lasers to flexible dielectric-lined hollow metallic waveguides" |
Description | Supporting data for paper "Efficient coupling of double-metal terahertz quantum cascade lasers to flexible dielectric-lined hollow metallic waveguides", available at: http://dx.doi.org/10.1364/OE.23.026276. Data were taken between May 2014 and June 2015. |
Type Of Material | Database/Collection of data |
Year Produced | 2015 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/249004 |
Title | Research data supporting "Fast modulation of terahertz quantum cascade lasers using graphene loaded plasmonic antennas" |
Description | This research data supports "Fast modulation of terahertz quantum cascade lasers using graphene loaded plasmonic antennas" which has been published in "ACS Photonics". |
Type Of Material | Database/Collection of data |
Year Produced | 2016 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/253983 |
Title | Research data supporting "Fast room temperature detection of terahertz quantum cascade lasers with graphene loaded bow-tie plasmonic antenna arrays" |
Description | Imaging folder: it contains all the pictures and datasets of two leaves acquired in the terahertz frequency range and in the visible. In the Leaf1 subfolder are reported the text files (.dat), the matlab files (.fig), and figures (.jpg) for different backgate voltages of the detector. The NEP*.*.opj are origin files containing the data set relatives to the Noise-equivalent-power in different biasing configuration of the detector; positive forward bias (forward3mv,forward5mv), zero bias(0mV) and negative bias (reverse3mv). The detection.opj file contains the detection measurements obtained by blocking and unblocking the THz light onto the detector, at different back-gate voltages; this set of measurements was acquired on 12/2015. The correct_incorrect_polarization.opj and the forward_reverse_bias.opj are origin files containing the data sets relative to the detection experiments with the correct incident light polarization and incorrect one and in the forward and reverse biasing conditions, respectively. This data set has been acquired on 4/2016. The S11Data.txt are the text set data of the simulated reflectivity from the bow-tie arrays obtained by the Comsol simulations for different graphene conductivity values. These data set are also reported in the S11_data.opj origin file. TDS_resonance.opj and TDS_Map.fig are the origin file containing the measured terahertz reflectivity with a broadband frequency source of the detecting array used for the imaging at different back-gate voltages, and the matlab figure reflectivity map for all the arrays, respectively. The Electrical_sd_characterization.opj contains the electrical characterization of the device; it reports the resistance between source and drain contacts by varying the back-gate voltage and at different forward/reverse biases. These data are also reported in the matlab figure file Electrical_SD.fig. Dirac_point.opj is the origin file containg the source-drain resistance at different back-gate voltages needed in order to identify the graphene Dirac point. |
Type Of Material | Database/Collection of data |
Year Produced | 2016 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/260277 |
Title | Research data supporting "Fast terahertz imaging using a quantum cascade amplifier" |
Description | Supplementary data for figure 2, 3, and 4 supporting 'Fast terahertz imaging using a quantum cascade laser' publication in Applied Physics Letters. |
Type Of Material | Database/Collection of data |
Year Produced | 2015 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/248771 |
Title | Research data supporting "Investigation of hollow cylindrical metal terahertz waveguides suitable for cryogenic environments" |
Description | Data supporting the figures from the paper. |
Type Of Material | Database/Collection of data |
Year Produced | 2016 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/260999 |
Title | Research data supporting "On Chip Andreev Devices: hard Superconducting Gap and Quantum Transport in Ballistic Nb-In0.75Ga0.25As quantum well-Nb Josephson junctions" |
Description | Onchip Andreev devices and Ballistic Josephson junctions fabricated, and measured by the authors at the Cavendish Laboratory, University of Cambridge UK, in the period Jan 2016 to April 2017. The measurements were done at low temperature (50 to 800 mK). The experimental methods are described in the associated publication. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/266821 |
Title | Research data supporting "On-chip hybrid Superconducting-Semiconducting Circuit for Scalable Quantum Computing" |
Description | In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting (S-Sm) circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. |
Type Of Material | Database/Collection of data |
Year Produced | 2019 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/298779 |
Title | Research data supporting "Proximity induced superconductivity in indium gallium arsenide quantum wells" |
Description | The hybrid Josephson junctions fabricated, and measured by the authors at the Cavendish Laboratory, University of Cambridge UK, in the period Jan 2016 to April 2017. The measurements were done at low temperature (50 to 800 mK). The experimental methods are described in the associated publication. |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/332625 |
Title | Research data supporting "THz nanoscopy of plasmonic resonances with a quantum cascade laser" |
Description | The dataset contains all the experimental data required to reproduce the Figures. The profiles can be extracted from the original files. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
Title | Research data supporting Bolometric detection of terahertz quantum cascade laser radiation with graphene-plasmonic antenna arrays |
Description | This dataset is of support of the publication Bolometric detection of terahertz quantum cascade laser radiation with graphene-plasmonic antenna arrays |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
Title | Research data supporting [External amplitude and frequency modulation of a terahertz quantum cascade laser using metamaterial/graphene devices] |
Description | This directory contains the data relating to the figures in "External amplitude and frequency modulation of a terahertz quantum cascade laser using metamaterial/graphene devices". Each xlsx file name describes which figure it is referring to. In each xlsx file the x and y axis of the figures are described. For any clarification or support, contact Stephen Kindness at sjk80@cam.ac.uk or stephenk530@gmail.com. |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
Title | Research data supporting [Probing the topological surface state in Bi2Se3 thin films using temperature-dependent terahertz spectroscopy] |
Description | Strong spin-momentum coupling in topological insulators give rise to topological surface states, protected against disorder scattering by time reversal symmetry. The study of these exotic quantum states not only provides an opportunity to explore fundamental phenomenon in condensed matter physics such as the spin hall effect, but also lays the foundation for applications in quantum computing to spintronics. Conventional electrical measurements suffer from substantial bulk interference, making it difficult to clearly identify topological surface state from the bulk. We use terahertz time-domain spectroscopy to study the temperature-dependent optical behavior of a 23-quintuple-thick film of bismuth selenide (Bi2Se3) allowing the deconvolution of the surface state response from the bulk. The signatures of the topological surface state at low temperatures (< 30 K) with the optical conductance of Bi2Se3 exhibiting a metallic behavior are observed. Measurement of carrier dynamics, obtain an optical mobility, exceeding 2000 cm2/V•s at 4 K, indicative of a surface-dominated response. A scattering lifetime of ~0.18 ps and a carrier density of 6×1012 cm-2 at 4 K were obtained from the terahertz time-domain spectroscopy measurement. The terahertz conductance spectra reveal characteristic features at ~1.9 THz, attributed to the optical phonon mode, which becomes less prominent with temperature. The electrical transport measurements reveal weak antilocalization behavior in our Bi2Se3 sample. We obtain the number of surface state modes, a as 0.5, and the coherence length, Lf, as 380 nm at low temperatures < 10 K, further confirming the presence of a single topological surface state mode. |
Type Of Material | Database/Collection of data |
Year Produced | 2018 |
Provided To Others? | Yes |
URL | https://www.repository.cam.ac.uk/handle/1810/273233 |
Title | Terahertz photonic integrated circuit for frequency tuning and power modulation - dataset |
Description | |
Type Of Material | Database/Collection of data |
Year Produced | 2020 |
Provided To Others? | Yes |
URL | http://archive.researchdata.leeds.ac.uk/636/ |
Description | Collaboration with CityU Hong Kong on THz spectroscopic sensors |
Organisation | City University of Hong Kong |
Country | Hong Kong |
Sector | Academic/University |
PI Contribution | Developoment of sensing techniques based on uni travelling carrier photodetectros based at UCL |
Collaborator Contribution | Development of an integrated spectroscopic tool for gas sensing |
Impact | The partnership is just starting so no outcome yet |
Start Year | 2016 |
Description | Collaboration with NPL on metrology for THz communication |
Organisation | National Physical Laboratory |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Co-funded a PhD student, who was collocated on both side. A particular interest in measurement and impact of phase noise on wireless THz links. This has led to important contribution to the field and developments in coherent digital THz wireless link fully transparent to optical networks. |
Collaborator Contribution | NPL funded half of the PhD fees and stipend, gave access to their laboratory for measurements of spectrum and lend an interferometer to UCL. Further, NPL co-supervised the PhD student and gave advise on measurements, metrology and traceability. |
Impact | Luis Gonzalez-Guerrero, Haymen Shams, Irshaad Fatadin, Member, IEEE, Martyn J. Fice, Member, IEEE, Mira Naftaly, Alwyn J. Seeds, Fellow, IEEE, and Cyril C. Renaud, "Single sideband signals for phase noise mitigation in wireless THz-over-fibre systems," Journal of Lightwave Technology, Vol. 35, 2018 Luis Gonzalez-Guerrero, Haymen Shams, Irshaad Fatadin, Martyn Fice, Mira Naftaly, Alwyn Seeds, Cyril Renaud, "Spectrally Efficient SSB signals for W-band Links Enabled by Kramers-Kronig Receiver," Optical Fiber Communication Conference, San Diego, 2018 L. Gonzalez-Guerrero, H. Shams, M. J. Fice, A. J. Seeds, I. Fatadin, M. Naftaly, F. Van Dijk, C. C. Renaud, "Experimental Investigation of Phase Noise Tolerance of SSB THz Signals," IEEE Topical meeting on Microwave Photonics, MWP 2017, Beijing, China, 2017 L. Gonzales-Guerrero, H. Sjams, M. J. Fice, A. J. Seeds, M. Naftaly, C. C. Renaud, "Experimental investigation for laser linewidth tolerance on photonic THz wireless systems using PE algorithms," Optical Terahertz Science and Technology, OTST 2017, London 2017 L. Gonzalez-Guerrero, H. Shams, M. J. Fice, A. J. Seeds, F. van Dijk, C. C. Renaud, "Linewidth Tolerance for THz Communication Systems Using Phase Estimation Algorithm," IEEE Topical meeting on Microwave Photonics, MWP 2016, Long Beach, US, 2016. |
Start Year | 2015 |
Description | Collaboration with Rutherford Appleton Laboratory and European Space Agency |
Organisation | European Space Agency |
Country | France |
Sector | Public |
PI Contribution | Development and design of high power high speed photodetectors, to be used as millimetre wave optically pumped oscillators |
Collaborator Contribution | ESA is funding the work while STFC-RAL is developing the packaging and modelling heat management. |
Impact | So far we have demonstrated a lower bias high performance high speed photodetector. |
Start Year | 2016 |
Description | Collaboration with Rutherford Appleton Laboratory and European Space Agency |
Organisation | Rutherford Appleton Laboratory |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Development and design of high power high speed photodetectors, to be used as millimetre wave optically pumped oscillators |
Collaborator Contribution | ESA is funding the work while STFC-RAL is developing the packaging and modelling heat management. |
Impact | So far we have demonstrated a lower bias high performance high speed photodetector. |
Start Year | 2016 |
Title | NITROGEN IMPLANTED ULTRAFAST SAMPLING SWITCH |
Description | A method of manufacturing a semiconductor device suitable for optoelectronic switching in response to light of wavelengths in the range 1200 nm to 1600 nm, comprising forming an undoped InGaAs layer on an insulative semiconductor substrate and bonded on opposed sides to a pair of electrical contact layers adapted to constitute the electrodes of a switch, comprising forming the bulk point defects by irradiating the InGaAs layer with Nitrogen ions. |
IP Reference | US2013029453 |
Protection | Patent application published |
Year Protection Granted | 2013 |
Licensed | Yes |
Impact | Commercially confidential. |
Title | Photodetector |
Description | High performance high frequency photodiodes. |
IP Reference | US20090184383 |
Protection | Patent granted |
Year Protection Granted | |
Licensed | Commercial In Confidence |
Impact | Has enabled the realisation of a range of microwave photonic systems and the technique is used in photodiodes manufactured by several companies. |
Title | SEMICONDUCTOR DEVICE FOR OPTOELECTRONIC SWITCHING |
Description | A method of manufacturing a semiconductor device suitable for optoelectronic switching in response to light of wavelengths in the range 1200 nm to 1600nm, comprising forming an undoped InGaAs layer on an insulative semiconductor substrate and bonded on opposed sides to a pair of electrical contact layers adapted to constitute the electrodes of a switch, comprising forming bulk point defects by irradiating the InGaAs layer with Nitrogen ions. |
IP Reference | EP2551920 |
Protection | Patent granted |
Year Protection Granted | 2013 |
Licensed | Yes |
Impact | Commercially confidential. |
Title | Semiconducting optoelectronic switch for THz operation using undoped InGaAs with defects created by N-ion implantation. |
Description | A semiconductor device suitable for optoelectronic switching in response to light of wavelengths in the range 1200 nm to 1600nm, may include an undoped InGaAs layer 7 on an semi-insulating semiconductor substrate, 4, such as InP, and bonded on opposed sides to a pair of electrical contact layers 6a, 6b adapted to constitute the electrodes of a switch. The InGaAs layer has bulk point defects formed by irradiating the InGaAs layer with Nitrogen ions preferably using an implantation energy of 1-10 MeV. This causes displaced Ga or As sites to form carrier traps for SRH recombination of photo-carriers, with a concentration of traps between 10^16 and 1^19 cm^3. The N-ions preferably penetrate the InGaAs layer and come to rest in the underlying InP layer (see figure 6) . The device may be formed as meas-structure with interdigitated electrodes (2a,2b with 2c,2d in fig 2a; or 3a,3b with just 3c in fig 2c). Waveguide structure may be provided for the electrodes as figures 3a-3b show with the device mesa marked as 1. The device may have a switch-off time of less that 10ps to less than 1ps and may be used to generate or detect sub-pico-second pulses in applications operating in 100 Ghz to 10 Thz. |
IP Reference | GB2493193 |
Protection | Patent granted |
Year Protection Granted | 2013 |
Licensed | Yes |
Impact | Commercially confidential |
Description | Big Bang schools event - Alexandra Palace |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Presented research-inspired interactive exhibits as part of the BIg Bang schools event aimed at increasing the interest and engagement of (mainly) secondary school children in science and engineering. Held at Alexandra Palace, London. |
Year(s) Of Engagement Activity | 2014 |
Description | Big Bang schools event - Newham College |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Presented research-inspired interactive exhibits as part of the BIg Bang schools event aimed at increasing the interest and engagement of (mainly) secondary school children in science and engineering. Held at Newham College, London, 30 June 2015. |
Year(s) Of Engagement Activity | 2015 |
Description | Big Bang schools event - Westminster Kingsway College |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Presented research-inspired interactive exhibits as part of the BIg Bang schools event aimed at increasing the interest and engagement of (mainly) secondary school children in science and engineering. Held at Westminster Kingsway College, London on 1 July 2015. |
Year(s) Of Engagement Activity | 2015 |
Description | KTN Photonics group book launch at Science Museum |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Interactive tabletop display related to photonic THz systems to help illustrate the range of photonics applications being investigated in the UK. Part of the launch of the Photonics - Revolutionising Our World publication by the Photonics group of the Knowledge Transfer Network on behalf of the UK photonics community and the Photonics Leadership Group. Evening event held at the London Science Museum on 19 June 2015, reaching over 200 people from postgraduate students to policymakers. |
Year(s) Of Engagement Activity | 2014 |
Description | Photonics Open Day 2015 |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | UCL hosted a Photonics Open Day to coincide with the International Year of Light. Over 70 school children (6th form students from across the region) visited the London Centre for Nanotechnology and the Electronic and Electrical Engineering Department where they heard talks about photonics and terahertz. This coincided with the International Year of Light 2015. |
Year(s) Of Engagement Activity | 2015 |
Description | Physics at work |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Physics at work takes place every year at the Cavendish Laboratory. A total of 2000 school students visit to listern to talks and demonstrations. My research group gives around 20 presentations to 25 students each year about semiconductor physics. Heightened interest in science and particular physics amongst local school students. Physics undergraduates are currently at record numbers in Cambridge. |
Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014 |
URL | http://www-outreach.phy.cam.ac.uk/physics_at_work/ |
Description | Royal Society's 'Quantum of Spin' Summer Science Exhibition |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | High profile exhibition about quantum technologies with links to photonics and terahertz research at UCL particularly highlighted. |
Year(s) Of Engagement Activity | 2012 |
Description | Short Course to CityU student in Hong Kong on THz coherent photonic systems |
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 | Special lecture for all Hong Kong postgraduate students in technology and Physics as part of a workshop on advanced technology at CityU. expected attendance is 80 |
Year(s) Of Engagement Activity | 2016 |
Description | Short course on THz photonics |
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 was the first day of a summer school on THz photonic technologies which was advertised across the world to the scientific community and graduate/doctoral schools. This first day was an introduction to THz photonics technologies and their impact on application, before the participants could engage with more focus subjects in the next few days. |
Year(s) Of Engagement Activity | 2021 |
Description | UK Terahertz Day - Lobbying for the formation of a UK THz Network funded by the EPSRC |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | 80 academic and industry guests attended the UK's first Terahertz Day workshop/conference event at Cambridge. There were keynote talks on terahertz activity from companies such as Teraview and then each of the major THz research labs in the UK highlighted their work with a view to set up new collaborations and lobby for the creation of a THz Network group funded by the EPSRC. This was successfully set up and is lead by Professor John Cunningham (Leeds). |
Year(s) Of Engagement Activity | 2013 |
URL | http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/M00306X/ |
Description | Video for schools: "Exploring the Last Frontier of the Electromagnetic Spectrum" |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Schools |
Results and Impact | We produced a video with involvement from Investigators and RAs on COTS aimed at educating school children about the importance of THz, photonics and engineering more generally, particularly in the International Year of Light 2015. The video is available at: https://youtu.be/7FY5kbvBbic. To date, the video has had over 300 Youtube views. |
Year(s) Of Engagement Activity | 2015 |
URL | https://youtu.be/7FY5kbvBbic |