Everybody knows that diamonds are beautiful and ever-lasting jewels symbolising purity and commitment. What might surprise you is that the heavenly purity of diamonds can be used in quantum technology devices with unprecedentedly high performance. DIADEMS, a FP7 FET project working with ultrapure diamonds developed high tech multi-functional measuring devices that will be used in medicine and computer science.

Quantum technology builds on quantum theory, which describes the behaviour of microscopic objects such as atoms and photons, which is different from that of objects that we observe in our daily life. Over the years, quantum technology has led to amazing innovations (computers, the internet and much more) that to a large extent shape today’s society. It is now attempting to develop methods for measuring and controlling individual atoms and photons: no wonder that work in this area won the 2012 Nobel Prize in Physics! Nowadays quantum research is raising the prospect of medical sensors that diagnose disease with nothing more than a breath sample, or extremely sensitive MRI scanners the size of smartphones – the focus of the research of DIADEMS.  The project is making use of the special properties of doped ultra-pure diamonds in quantum technology to develop extremely sensitive measuring and detection devices.

We interviewed the scientific coordinator of DIADEMS, Thierry DEBUISSCHERT from Thales Research & Technology-France.

Thierry, how exactly are you using diamonds in your research?

For our research we are using ultrapure artificial diamonds that include a special defect called a nitrogen vacancy (NV) centre. The unique physical properties of such centres allow us to build uniquely sensitive sensors and probing devices for magnetic field measurement. An example of such devices could be scanning probe magnetometers - devices that detect and map magnetic fields with very high sensitivity and at an extremely high resolution, and can tell us how a field spreads around its source and how strong it is. Magnetic field distribution mapping is a practice commonly used, for example, when one needs to know why an electronic circuit is malfunctioning. Another example of a magnetic field measurement-based device could be a wide-field magnetic imager (a powerful tool for probing biological and physical systems).

What do you think are the greatest scientific challenges in this project?

Our quantum technology devices have unprecedented sensitivity, being able to measure magnetic fields a thousand times smaller than the earth's field. These measurements can be made at a minute scale - the technique enables readings to be taken over remarkable distances less than a thousand times smaller than the width of a human hair.

Was there a challenge the FET programme helped you to overcome?

A great challenge many researchers face is transferring their technology from the research lab to a pre-development stage. We achieved that by establishing a close collaboration between academia and industry. To do this we had to bring together the main European actors in the field.

The structure of the FET programme gave us a unique framework for intra-European collaboration in this research. The financial support from the Commission helped a lot in developing the technology and also the transfer to industry. It allowed the project to achieve results beyond what was planned at the beginning.

What are the key achievements of DIADEMS, the ones you are most proud of?

DIADEMS has produced tools which measure magnetic fields for several applications. The fact is, in several fields of physics there is no other tool with such a high performance available at the moment. The devices we developed are mainly usable in two fields.

First, they enable new and more in-depth research in physics and biology that was not possible before. For physics, diamond scanning tips make possible the investigation of new kinds of magnetic materials at scales hardly accessible before. Highly sensitive detectors designed to measure very tiny magnetic fields have been developed. The technology was used to make new photonic devices (tools using light), which improved the sensor's ability to detect fluorescence emitted by the NV centres. The project also developed improved Nuclear Magnetic Resonance (NMR) techniques for biological research which has enabled, for instance, the study of individual atoms within a protein molecule. Mastering this technique would open up a range of biomedical applications, including nanomedicine platforms for the delivery of drugs, genes or proteins, and multifunctional intracellular sensing. In addition, the project developed special microscopes such as a combined atomic force microscope and confocal microscope which can "see" at an atomic scale in ways that were impossible before, working at unusually low temperatures.

Second, besides research, specialised diamond sensors have also been used for measuring the performance of read/write heads for high density hard disks in computers. We also developed a device for producing images of the magnetic field over large areas, which enables us to localize imperfections in electronic circuits. This tool works at room temperature and in normal atmospheric conditions, which is a significant advance compared to present solutions using scanning sensors working in vacuum and at cryogenic (extremely low) temperatures. We also came up with innovations that were not planned or predicted by our project. They will allow for more compact devices based on electrical detection of the signal produced by the NV centre, monitoring of the signal used in WiFi communications, and lower consumption electronic memories based on new magnetic materials for lower cost and better performance.

It is important to say that our experimental work has been enriched by close collaboration with theoretical teams, which provided new protocols for using NV centres, in particular based on quantum information techniques.

How will DIADEMS change the life of European citizens?

First of all, our technology can be used to improve MRI machines used for scanning patients and diagnosing diseases, which can then be reduced in size and use lower magnetic fields and smaller magnets. Such improvements will make those machines more affordable and thus more accessible for European citizens, improving their healthcare. Similarly, our technology will enable more sensitive Nuclear Magnetic Resonance with higher resolution capacity for application in drug design. In the field of computer science, our technology can be used to build high density storage disks with higher capacity than we have now. Applying our research to spintronics-based logic devices (logic devices working with electron spin instead of electron charge), which are nowadays being heavily studied, will contribute to more energy-efficient, higher performance computers.

European scientists are recognised as world leaders in quantum technologies, but commercial exploitation of this knowledge has not always taken place in Europe. How easy has it been for the DIADEMS partners to put the project's results into action?

Several of the results of the DIADEMS project are being deployed in Europe. An Atomic Force Microscope combined with a confocal microscope using a single NV centre sensor has been developed for commercial use by the partner Attocube.  Four start-ups have been launched as direct spin-offs of several project partners:  NVision, SQUTEC, QNAMI, and QZABRE. As a result of its participation in the project, partner Element 6 has now an increased portfolio of advanced materials based on NV centres in diamonds. The strong collaboration between the academic and industrial partners during the project played a key role in facilitating this transfer of knowledge.

How do you see the results from DIADEMS contributing to the future FET Flagship on quantum technologies?

The DIADEMS project has helped to structure the research community working in quantum sensing through collaboration with other FET projects and national projects (e.g. initiating collaborations as part of the QUANTERA ERA-NET scheme). It has made a strong contribution to the definition of the Quantum Technology Flagship.  

What advice would you have for young researchers or students interested in a career in research?

Be open to new developments in research. Do not neglect applications of your work.  Be concerned both by theory and experimental research – both are deeply intertwined!

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