... in particular for sensing heart and brain activity, dosing biological molecules in body fluids. In order to be effective, sensing devices like magnetometers must be able to measure very weak magnetic fields. Such devices exist; however, they are too expensive and complex to operate to be widely adopted in medical centers.
Nitrogen vacancies in diamond are excellent candidates to measure very weak magnetic fields in an affordable way and replace the existing solutions.
What are these nitrogen vacancies? Diamond has remarkable properties, most of them coming from the fact that carbon is the lightest element to be able to form three-dimensional crystals. Most of all, it possesses a wide bandgap and can be doped with a variety of impurities, that constitute as many color centers. The most common one is substitutional nitrogen. It is typically incorporated during chemical vapor deposition (CVD). Combined with a carbon lattice vacancy, substitutional nitrogen center forms a so-called Nitrogen vacancy (NV). It possesses remarkable properties that makes it very useful to many quantum-related applications. External magnetic field interacts with the spin of these quantum states and shifts their energy levels. This shift can be measured with a combination of electromagnetic radiations, in the microwave and optical frequency ranges.
The accuracy is comparable to the best systems currently used in hospitals. The key difference is their simplicity of use, in particular the diamond-based magnetometers can be used at room temperature.
LakeDiamond collaborates with EPFL professor Christophe Galland on this promising topic and was recently granted with an EPFL Innovator project funding for this activity.