International exchange award: Widefield microscopy for quantum sensing using Nitrogen Vacancy (NV) centres in diamonds

Prof. Chu and PhD students (Jiahua, Michael and Xinhao) with Julien Roth at the University of Hong Kong.

Julien Roth, PhD student at the University of Cambridge was awarded an M4QN international exchange grant to visit Prof. Zhiqin Chu at the University of Hong Kong (HKU). The visit took place from 19th-30th January 2025.

Widefield microscopy for quantum sensing using Nitrogen Vacancy (NV) centres in diamonds

The aim of the exchange was to learn from the groups expertise in building widefield microscopy setup for quantum sensing using Nitrogen Vacancy (NV) centres in diamonds. Currently the most widely used microscopy technique for NV centres is confocal microscopy. This technique allows for great spatial resolution but has the drawback of being very localised and only provides very little wide scale information. Widefield microscopy is an alternative approach which sacrifices some of the spatial resolution for a much larger field of view.
Prof. Chu’s group has built more than one widefield setup, including one incorporated on a confocal setup, allowing to switch between the two microscopy techniques. The group members shared knowledge of each setup, detailing the choices they made and hardware chosen. The exchange allowed Julien time to study in detail the optical setup in place and become familiar with the principles and limitations involved, leading towards the construction of one in the UK.

Benefits to the UK materials and quantum community

Julien says “Building our own widefield imaging setup will enable us to measure and spatially map physiochemical properties on the nanoscale for in vitro and in vivo systems. Measurement such as mapping the concentration of reactive oxygen species will further our understanding of emergent phenomena in complex biological systems at these scales. Furthermore, the experience gained from this exchange will contribute significantly to collaborative efforts within the network. By sharing the knowledge and expertise acquired during the visit, I hope to accelerate our collective progress towards building large scale quantum biosensing capabilities.”

New collaboration

The exchange is expected to start a longer lasting collaboration between the two groups who are interested in studying similar processes, and can benefit from each others expertise. Julien has discussed the possibility of future visits for extended stays. The visits would build on some of the discussions held during the exchange, and on the work that is being done in the coming months. The group at HKU have also developed a technique that allows them to have brighter nanodiamonds than the ones commercially available which they can share, enabling new experiments and privileged access to state of the art resources for new experiments.