Ultrasensitive optomechanical spin sensing

Research Project, 2024 – 2027

Magnetic resonance force microscopes image magnetic fields at sub-nanometer scales, potentially enabling three-dimensional mapping of biomolecules and nondestructive characterization of delicate quantum devices. Single atom resolution is a longstanding goal of the field, but the current generation of sensors are limited by the thermal force fluctuations of the mechanical resonator, and thereby prevented from sensing the magnetic field of single atoms. Recently, strained thin-film mechanical resonators have reached much higher force sensitivity, but have yet to be adapted for sensing magnetic fields. In this project, we will realize on-chip systems that are capable of single-spin readout by functionalizing coupled mechanical resonators with nanomagnets. We will couple these mechanical resonators to photonic crystal optical cavities and implement sensitive on-chip optical readout. These systems will have unprecedented force sensitivity and attain the elusive goal of sensing single proton spins, thereby unleashing the full potential of magnetic resonance force microscopy for atom-by-atom imaging of complex molecules. We will probe the classical and quantum limits to force sensitivity of the system and develop new methods for increased sensitivity. The project will be conducted by a PhD student and I at Chalmers University of Technology. The PhD student will be primarily responsible for nanofabrication of the devices in the Chalmers Nanofabrication Laboratory.