Fibre-Based Fast T-ray Tomography
Lead Research Organisation:
University of Southampton
Department Name: Optoelectronics Research Ctr (closed)
Abstract
The aim of this project is to demonstrate THz tomography, operating at millisecond image frame rates. We propose to design, build and characterise a fast multi-channel THz tomography system without moving parts, utilising a new THz source based on short-pulse fibre lasers driven by high-power laser-diodes. The output of the fibre lasers will be combined to produce THz emission by difference-frequency generation. The character of the THz emission from the proposed source allows inexpensive pyroelectric detector arrays to be used. A large number of THz measurement channels will be realised as a parallel and re-configurable data acquisition and processing electronic system. The breakthrough in speed and facility of THz tomography will be achieved via novel solutions in: fibre lasers; THz optical train (difference-frequency generation, beam conditioning, detector geometry); signal acquisition and processing; methods for image reconstruction. The proposed technology will also open the way to fast benchtop THz tomographs with applications in a wide area of science and engineering.We propose a demonstrator experiment which will employ this novel THz tomography system to map major species' concentrations and temperature field distributions in high-pressure flames. These flames are opaque to the usual IR analysis techniques because of scattering from the soot particles, but have been shown by the applicants to be transparent to THz radiation. In addition, many of the species in these flames exhibit absorption resonances in the THz region. THz tomography therefore promises to be the only way to study high pressure flames. This has important implications in our understanding of the combustion processes in, for example, aero engines with the possibility of improving efficiency and reducing emissions of greenhouse gases. We'll demonstrate at least the following performance in the case of high-pressure flames in the presence of soot: image frame acquisition period <1ms; maps of the cross-sectional distribution of major species with spatial resolution (in area) of D2/64; maps of distribution of temperature (T~1000K) of water molecules. This project is a direct consequence of the THz Basic Technology work funded by RCUK and combines established expertise in tomography (Manchester), THz technology (Leeds) and novel laser sources (Southampton). The synergy between the currently running Basic Technology THz work and this project will allow the identification of the spectral behaviour of the chemical species in the flame under realistic conditions and indicate the best choice of spectral lines for temperature mapping. The project is a crucial step towards THz tomography for imaging of gas mixture systems and a variety of other objects, with expected strong impact on the future utility and affordability of the THz technology.
Publications
Shen Y
(2009)
PPMgLN-Based High-Power Optical Parametric Oscillator Pumped by Yb $^{ {\bm 3}{\bm +}}$-Doped Fiber Amplifier Incorporates Active Pulse Shaping
in IEEE Journal of Selected Topics in Quantum Electronics
Richardson D
(2010)
High power fiber lasers: current status and future perspectives [Invited]
in Journal of the Optical Society of America B
Malinowski A
(2012)
Fiber MOPA based tunable source for terahertz spectroscopy
in Laser Physics Letters
Malinowski A
(2009)
High power pulsed fiber MOPA system incorporating electro-optic modulator based adaptive pulse shaping
in Optics Express
ANDREW MALINOWSKI
(2009)
THz Spectroscopy to Tomography
A MALINOWSKI
(2011)
Fiber MOPA Based Tunable Source for Terahertz Spectroscopy
Description | During this project we developed a compact source of THz radiation based on the frequency mixing of the output of a two wavelength fibre laser source. We achieved high power narrow linewidth output in the approximate range 1-3THz with ~1 GHz linewidth. We developed a spectrometer based on this source and illustrated high resolution spectroscopy of water vapour in air. |
Exploitation Route | We undertook a project with an industrial sponsor (Samsung) on a medical application of the spectrometer developed. Unfortunately the results were inconclusive and we suffered source reliability issues that hindered further detailed study. We have parked this research for the present. |
Sectors | Aerospace Defence and Marine Healthcare Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology Security and Diplomacy |
Description | The work we undertook on this project stimulated the interest of Samsung, who placed a contract with us to explore the possibility of using narrow-linewidth THz radiation to manipulate proteins. The studies proved inconclusive in the end and the project was ultimately put on hold. |
First Year Of Impact | 2012 |
Sector | Healthcare,Manufacturing, including Industrial Biotechology |
Impact Types | Societal |
Description | SAMSUNG Global Research Outreach Scheme |
Amount | £100,000 (GBP) |
Organisation | Samsung |
Sector | Private |
Country | Korea, Republic of |
Start | 12/2012 |
End | 11/2013 |
Description | SPI Lasers UK Ltd |
Amount | £80,000 (GBP) |
Funding ID | UOS08888 |
Organisation | SPI Lasers UK |
Sector | Private |
Country | United Kingdom |
Start | 01/2013 |
End | 09/2013 |
Description | TSB - Laser Based Manufacturing |
Amount | £320,000 (GBP) |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 09/2009 |
End | 10/2012 |
Description | Collaboration on THZ source development and testing |
Organisation | University of Leeds |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Development of fibre based THZ source. |
Collaborator Contribution | Test of source and associated spectrometry trials on water vapour. |
Impact | Technical papers (see publication list). |
Start Year | 2009 |
Description | Collaboration on THZ source development and testing |
Organisation | University of Manchester |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Development of fibre based THZ source. |
Collaborator Contribution | Test of source and associated spectrometry trials on water vapour. |
Impact | Technical papers (see publication list). |
Start Year | 2009 |
Description | Royal Society Summer Exhibition 2008 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Demonstrated the impact of optical fibre technology in the internet and laser based manufacturing. Large amount of PR Press interviews School children visits etc |
Year(s) Of Engagement Activity | 2008 |
URL | https://royalsociety.org/summer-science/2008/ |