A commercial THz imaging system using Lumped Element Kinetic Inductance Detectors

Lead Research Organisation: Cardiff University
Department Name: School of Physics and Astronomy

Abstract

Detector arrays are used in many familiar technologies for forming images of the world we live in. The most common detector array known as the charged coupled device (CCD) array forms the basis of many digital and phone cameras. Such detector arrays are sensitive to light in the optical region of the electromagnetic spectrum (the colours of the rainbow - red through to blue). However there is a wealth of information contained in the regions of the electromagnetic spectrum outside of the range of the human eye. For example you may have seen infrared images taken from police or rescue helicopters using special cameras searching at night. Infrared light is no different to optical light and in most cases is generated by the same mechanism - heat. If one were to heat a piece of metal to a few hundred degrees centigrade we would notice it glowing red. Heat it further and it would glow yellow then white. If we let it cool again we would see the white glow fade to yellow which would fade to red and then to no glowing at all. In fact this is not the case. The metal is now glowing in a region of the electromagnetic spectrum known as the infrared. The only reason we do not observe this is because our eyes are insensitive to this light. We can however sense infrared light and it is what we more commonly refer to as heat. If one moved their hand near a warm piece of metal (such as a household radiator) without touching it we would feel that it was hot from the infrared radiation warming our skin. If the metal were to cool back down to room temperature it would still be glowing in the infrared but now much less intensely. The infrared region of the spectrum lies just beyond the red region of the visible spectrum but as we move further past the infrared from the visible spectrum we enter what is known as the THz region of the electromagnetic spectrum. The THz region of the spectrum is of great interest to research and industry alike. For example many materials that are opaque to visible light are transparent to THz light. In this example if one had an array of THz detectors one could image objects beneath a surface that would otherwise be invisible. You may have experienced such systems in some airports where they are used for security purposes to detect concealed objects on passengers. Beyond security, the imaging of THz light has many applications ranging from quality control (imaging the invisible circuitry of an encased computer chip for example) to looking at the THz light emitted from biological samples used to deduce their chemical composition. However to date developing detectors that can sense THz light has proven complex and expensive hence THz imaging arrays are not commonplace in the world of research or industry.
The proposed research will develop a new type of detector called the Lumped Element Kinetic Inductance Detector (LEKID). The LEKID is sensitive not only to optical, THz and infrared light but also ultra-violet light and X-rays. The LEKID is also very simple to fabricate into large imaging arrays making it a viable option for the commercial and industrial applications. The one drawback of the LEKID is that it must be cooled to very low temperatures. Known as cryogenic temperatures the temperature the LEKID operates at is of order -273 degrees centigrade and is close to the lowest temperature physically possible referred to as absolute zero. However, recent development in cryogenic technology has made achieving these low temperatures relatively simple. Detectors operating at these low temperatures have significant advantage over their room temperature rivals, being of order 10,000 times more sensitive and generally much faster. This property allows for the first time THz imaging at video frame rates. The idea of a THz video has excited many research scientists as they would now have the ability to watch how a system emitting THz light evolves in real time which has never before been possible.

Publications

10 25 50
 
Description The award set out to develop a a camera capable of imaging at THz frequencies using a new type of detector known as a Kinetic Inductance Detector. The aim was to develop a camera that could be used for commercial purposes and focused on making a system that could be transferred to the commercial market. The project focused on security applications as there was a clear need for this technology in this area. Importantly, the system developed for working in the area of air passenger screening, proved the technology provides superior imaging when compared to the current technology used in airports around the world today.
Exploitation Route The clear outcomes of this project being used by others are the use of the technology and techniques developed being used by a spin out company Sequestim. Sequestim have already secured a licence agreement with Cardiff University and are directly leveraging on the outputs of this project to develop a revolutionary new technology to replace existing mm-wave security imaging systems in airports. The work carried out in this project has also contributed to the ongoing detector development program at Cardiff by supporting research in this area and accelerating the development of fabrication capabilities of superconducting detector arrays at Cardiff. Such fabrication techniques are currently being shared and transferred to the Institute of Compound Semiconductors (ICS) based at Cardiff.
Sectors Aerospace, Defence and Marine,Manufacturing, including Industrial Biotechology,Security and Diplomacy,Transport

URL https://sequestim.com
 
Description The work carried out during this award proved the capability of the technology developed directly leading to new start up company - Sequestim being formed. This company currently has two employees and is seeking rapid expansion to develop new security imaging systems spanning a range of sectors. The work completed has given the company confidence that it can attract investment funding to acquired the appropriates regulatory certification to enable such systems to be deployed in airports across Europe and the United States.
First Year Of Impact 2019
Sector Security and Diplomacy,Transport
Impact Types Economic

 
Description Future of Airport Security Solution
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Maritime border security - influence on Government upgrades to security screening techniques.
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description FASS 1
Amount £40,000 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 04/2017 
End 09/2017
 
Description FASS-2
Amount £400,000 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 02/2018 
End 01/2019
 
Description QuantIC Partnership Resource Phase 1
Amount £54,876 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2016 
End 04/2018
 
Description QuantIC Partnership Resource Phase 2
Amount £229,974 (GBP)
Organisation University of Glasgow 
Department QuantIC
Sector Academic/University
Country United Kingdom
Start 04/2018 
End 09/2019
 
Description Rapid Airport Security Screening Using Superconducting Technology - RASSUST
Amount £438,793 (GBP)
Funding ID ST/T003359/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 04/2020 
End 03/2023
 
Description QMCI Industrial Partner 
Organisation QMC Instruments Ltd
Country United Kingdom 
Sector Private 
PI Contribution My research team have developed a generic passive THz imaging system for use in industrial applications.
Collaborator Contribution Our industrial partner QMCI has provided cryogenic hardware and optical filters to make the final instrument build possible. QMCI has also made possible the formation of a new company dedicated to developing this technology for security applications.
Impact This collaboration has seen further funding being awarded from the UK Government for a phase 1 study funded by Innovate UK (Detection of Clandestines awarded to QMCI Ltd). Furthermore we have recently received phase 1 study funding under the Future Aviation Security Solutions (FASS) programme (awarded to Sequestim Ltd with funds expected to be passed to the research group at Cardiff). The partnership has also received funding for detector material development under the EPSRC Quantic hub programme.
Start Year 2015
 
Description SEQUESTIM 
Organisation Sequestim Ltd
Country United Kingdom 
Sector Private 
PI Contribution Scientific support for instrument development
Collaborator Contribution Provided man-power, project management and commercial expertise to move research ideas towards a commercially viable product.
Impact Acquired further funding to build and airport security demonstrator based upon output of existing grant. Acquired further funding for material development in collaboration with Glagow University.
Start Year 2016
 
Title Camera design including Kinetic Inductance Detectors and Metal Mesh Filters 
Description Our development involves the production of sub-mm wave cameras using Cardiff invented Detector and Filter technology. This technology is specialised and cannot be replicated by other groups. It has been licensed to SEQUESTIM ltd only for use in security applications. 
IP Reference  
Protection Protection not required
Year Protection Granted
Licensed Yes
Impact This unique combination of these two Cardiff technologies has enabled the effective realisation of passive THz imagers for security applications. This offers a versatile and robust security screening solution with high passenger throughput for application in all mass-transport hubs. Sequestim will aim to deploy demonstrator units within the next three years in partnership with major manufacturers.
 
Company Name Sequestim Ltd 
Description Sequester is a company specialising in the use of passive cryogenic detector technology working at mm-THz wavelength (100-1000 GHz) for security applications . 
Year Established 2016 
Impact This recently formed company received funding from he UK government under the Future of Aviation Security Solutions (FASS) programme to develop walk through passenger screening instrumentation.
 
Description FASS-2 Cardiff airport demonstration 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The camera developed as a result of this project was installed at Cardiff airport (land side, non-public location) to demonstrate its capabilities in a security imaging capacity to a number of representatives from the UK government, border force and industry. Attendees included:

Liverpool, Lydd, and Cardiff airports, the Glasgow Quantic Hub, DSTL, CPNI, Chester University, South Wales Police and ICST (consultancy company for Amazon)
Year(s) Of Engagement Activity 2018
 
Description FASS-2 Media coverage 
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 Media (as a channel to the public)
Results and Impact The camera resulting from this project was demonstrated in a security imaging capacity to a number of national journalists. Press releases were also issued to international journalists. Interviews were conducted for:

ITV (shown on national Ten o'clock news, December 4th)
BBC Wales (Multiple airings)
Heart FM

The syndicated press release was reviewed by more than 100 journals including UK national press, international hard copy and on-line trade magazines.
A special piece was published in the UK national news paper - The Times.
Year(s) Of Engagement Activity 2019
URL https://www.bbc.co.uk/news/technology-46906935
 
Description HM Government 
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 Several demonstrations of the capabilities of our developed technology to HM government officials (Centre of Applied Science and Technology and UK Borderforce).
Year(s) Of Engagement Activity 2015,2016
 
Description The London FASS Demonstration Event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The camera resulting from this project was demonstrated in a security imaging capacity to the Future Aviation Security Sector (FASS) project to more than 100 stakeholder organisation representatives.
Year(s) Of Engagement Activity 2019