International exchange award: Advancing Quantum Magnetometry
Posted on 3rd April 2025 in News
Charlie at dinner with the extended quantum photonics group at MIT, including PhD hosts, Sikder Bejoy (2nd from left), and Hanfeng Wang (5th from left) in honour of visiting Caltech Professor, Andrei Faraon. Charlie Patrickson a postgraduate researcher at the University of Exeter was awarded an M4QN international exchange award to visit Dr Matt Trusheim at MIT. During his visit Charlie also visited Sohini Sarkahr at Nokia Bell Labs and Carlos Meriles at City University of New York. The visits took place from 28th February to 7th March 2025.
Advancing Quantum Magnetometry
Charlie is based in Isaac Luxmoore’s group at the University of Exeter, where they develop quantum sensors using spin ensembles in two dimensional materials. Typically, they readout spin ensembles optically. In contrast, Dr Matt Trusheim’s group at MIT have pioneered using microwave fields to detect spin ensembles at room temperature. The technique has led to a significant enhancement in magnetometry performance. The visit allowed knowledge exchange between the two groups.
Charlie writes “To provide a benefit in sensing performance, microwave detection demands strong room temperature coupling between the spin ensemble and a microwave cavity. This is a recent development and Dr Trusheim’s group have overcome a spate of technical challenges to demonstrate the work. Visiting in person has allowed me to understand these requirements in detail; the group shared several experimental systems, after which I shadowed Postdoc Ethan Arnault and PhD student Bejoy Sikder. They also shared some recent unpublished results and invited me to present my research.
We hope to use this expertise in a collaboration with Nokia Bell labs, where I completed a quantum sensing internship in Cambridge last summer. In support, Nokia generously funded a visit to their New Jersey site during the same trip. This really helped me to understand their US capabilities and expertise, whilst expanding connections for future collaboration. The New Jersey Bell Labs site is steeped in academic history too, having hosted several Nobel laureates – it was a very cool place to see.”
Benefits to the UK materials and quantum community
These types of highly sensitive quantum magnetometers have been identified for applications in healthcare (e.g. magnetocardiography and magnetoencephalography), communications (e.g. fast, wideband spectrum analysers) and as navigation or rotation sensors. While the academic field is mature, there is an increasing drive from startups and established industrial partners to develop these technologies into viable commercial products. The trip supported this transition by imparting expertise to the UK quantum knowledge base whilst also laying the foundations for academic-industrial collaborations.
Charlie writes “By engaging with Dr. Matt Trusheim’s group—who have pioneered the development of these devices – I was able to gain insight into several critical aspects of their setup, including the performance and characteristics of microwave transmission lines and components, and their homodyne readout system. These elements have a critical bearing on magnetic field sensitivity. Potential applications would require size, weight and power optimisation and researchers at Nokia are interested in understanding trade-offs vs. performance. For example, can benchtop components be implemented on a printed circuit board, and if so, what are the critical components and how would this impact their function? I’ve started sharing this information with collaborators at Nokia, ensuring that this knowledge extends beyond my own research to benefit the broader UK quantum ecosystem.”
Visit Outcomes
Charlie writes “Dr Trusheim’s group are considering alternative spin systems for their microwave cavity setup. Performance depends on a relationship between the number of defects in a material and the inhomogeneous linewidth of the spin system. Although bulk crystals are small for two-dimensional materials there are some potential benefits. In hexagonal boron nitride for example, which has been the focus of my research, the spin density can be relatively high, and all defects share a common quantization axis. We will share these properties with Dr Trusheim’s group so they can assess potential performance, with material to follow if results are positive.
Regarding collaborations with Nokia, we are in the final stages of signing an NDA. This will allow us to discuss size, weight and power optimisation with scope for patent applications. I have also begun to share my learning with my internship programme managers to help inform their research and development programme. Following successful progress here we hope to apply for upcoming innovateUK calls.
Whilst visiting Nokia I also took the opportunity to visit and present my research to Professor Carlos Meriles’ group at City University of New York, where they use spin defects for electric field sensing, and analysis of microfluidics. Follow up discussions have proved fruitful, with both groups sharing a detailed comparison of experimental techniques and hardware. I would also highlight the benefit of building these connections in person – everyone I spoke to was knowledgeable and approachable, facilitating open discussions and establishing a strong foundation for ongoing collaboration.”