It all started with a request from network operator Alliander, which wanted to be able to locate underground infrastructure to prevent damage caused by excavation work. We were already working on quantum magnetosensors in Amsterdam, and in a project we demonstrated that these can be used to map underground infrastructure quite effectively. Subsequently, Rijkswaterstaat expressed an interest in detecting ‘dark vessels’ – ships that deliberately sail without an AIS (Automatic Identification System) signal. This was with a view to securing the North Sea, which is heavily trafficked and home to a great deal of critical infrastructure (wind farms, gas pipelines, and power and data cables). It has since become an extremely topical issue, given the threat of sabotage of this infrastructure by foreign powers. This led to the Stella Maris project, which was launched in 2025.
Marten Teitsma, Professor of Applied Quantum Computing, Amsterdam University of Applied Sciences:
“My ambition is to carry out compelling research that has a positive impact on society. In this project, we aim to develop a robust and seaworthy detection system for dark vessels, which will ultimately help make the Netherlands a safer place.”
Results
Quantum magnetic sensors can detect extremely small (changes in) magnetic fields based on quantum mechanical effects. Live cables naturally generate an (electro)magnetic field and can therefore be detected using these sensors. Even when no current is flowing through the cables, their magnetic properties mean they still have a small effect on the Earth’s magnetic field in which they are situated. In principle, this too can be measured using these sensors. The same applies to ships made largely of steel; their influence on the Earth’s magnetic field can also be detected using quantum magnetosensors.
At the heart of such a sensor is a tiny diamond containing NV centres; these occur naturally but can also be introduced using ion implantation techniques. NV centres (nitrogen-vacancy centres) are impurities consisting of a nitrogen atom and a ‘hole’ in the crystal lattice of diamond, which in principle contains only carbon atoms. These NV centres exhibit fluorescence: when green light is shone on them, red light is emitted. If the surrounding magnetic field changes, this affects the fluorescence: the emitted light takes on a slightly different wavelength, and that change can be measured.
Building on our research for Alliander, we have developed a measurement system based on a highly sensitive quantum magnetosensor. In doing so, we paid particular attention to suppressing noise (for example, from the photodiode used to measure the fluorescence signal) and other environmental disturbances (such as scattered light). We have successfully got the system up and running in the lab.
We then put a great deal of effort into making the system smaller for field deployment, by switching from laboratory equipment electronics to a PCB, and into making it more robust. This takes you from TRL (technology readiness level) 4 to TRL 6, which is a significant step, with conditions becoming much more challenging. This became apparent during the first field tests along the Amsterdam-Rhine Canal. The noise level was suddenly too high again; we are still working on reducing it. Once that has been achieved, we will continue with testing, so that we can detect, distinguish and categorise multiple ships simultaneously. The next step will then be testing in a port, and ultimately we want to deploy the system on a buoy in the open sea to prove that the principle works there.
In practical terms, this could involve using a line or even a grid of these systems to enable more accurate measurements and positioning. For maritime applications, there is no need to make the electronics any smaller, but this may be necessary for other applications. There is still scope for further development, as we have not yet prioritised compactness when selecting components.
In the meantime, we have also set up the entire information chain for this detection system. Starting with the sensor system, which may consist of several units each containing a laser, a diamond and a photodiode. The analogue signals produced by this are amplified and digitised, stored in a database and then processed by algorithms to produce a detection signal with location data for a dark vessel. The final result is displayed on a screen (GUI, graphical user interface).
Marcel van der Horst, Senior Lecturer and Researcher, Faculty of Technology and Amsterdam Sensor Lab, Amsterdam University of Applied Sciences:
"We have already involved many students in the research through sub-projects. For example, in the software, the power management of the sensor system and the sensor readout. Students find quantum sensors an interesting topic and they recognise the social impact. That’s really nice. Here at the university of applied sciences, we have no trouble at all getting students interested in projects in the sensor lab. My ambition now is to further miniaturise the electronics, ensure that the sensors can measure even more sensitively – partly by improving the readout – and make them even more energy-efficient. I currently have a final-year student working on that.”
Next steps
The next step is to expand the research by collaborating with partners who can contribute new expertise. These include universities of applied sciences specialising in electronics and software engineering, photonics companies for the further development of the light module, and semiconductor companies for the miniaturisation of the electronics module. A prerequisite for the latter, however, is that conventional electronics must first demonstrate that the concept works reliably and that there is a market for it; IC manufacturers will not invest until this has been established.
Furthermore, other applications could be explored, such as in medical technology (measuring the brain’s magnetic field, for example) or for GPS-free navigation (guided by the Earth’s magnetic field). A key focus here will be reducing costs by using as many off-the-shelf components as possible. This will make it commercially viable to produce and use the systems in larger numbers, perhaps also in Internet of Things-style applications.
Ari Ortiz Moreno, lecturer and researcher at the Applied Nanotechnology research group, Saxion University of Applied Sciences:
"My ambition is to find more applications. I’m a university graduate myself and did my PhD there; now I’m part of a research group at a university of applied sciences. It’s no longer about whether something is revolutionary, but whether it’s feasible to implement. With that focus in mind, I am looking for new use cases and companies we can involve in this. Not only for the development of new quantum sensors, which we can integrate with photonics, for example, but also for new electronics for quantum technology in a broader sense."
Partners
The project is being carried out on behalf of the North Sea Infrastructure Protection Programme (PBNI) of the Ministry of Infrastructure and Water Management, with Rijkswaterstaat acting as project manager. The research partners are Amsterdam University of Applied Sciences, Saxion University of Applied Sciences, Rotterdam University of Applied Sciences and High Tech Alliance, an SME based in Valkenswaard that specialises in custom machine building, high-tech product development and innovation consultancy.
