Long-Lived Mechanically Detected Molecular Spins for Quantum Sensing
Sahand Tabatabaei
Location: QNC 1201
Abstract
Quantum sensors based on individual spins provide access to local magnetic fields in condensed matter, chemistry, and biology, with solid-state defect spins emerging as a leading platform. Their application to molecular sensing, however, is constrained by confinement to a host lattice, which limits how closely the sensor can be positioned relative to a target molecule. Molecular spins offer an alternative, providing chemical tunability and flexible positioning relative to the system of interest.
In this talk, I will present SQUINT (Spin-based QUantum Integrated Nanomechanical Transduction), a nanoscale sensing platform combining molecular electron spins, ultrasensitive mechanical readout, and Hamiltonian engineering. Using a modified XYXY dipolar-decoupling sequence, we suppress electron-electron dipolar interactions across a broad distribution of control fields and extend coherence times to approximately 400 μs in an attoliter-scale sample containing approximately 100 trityl-OX063 radicals. We then use these long-lived spins for frequency-selective detection of nanotesla-scale AC magnetic fields and for sensing and spectroscopy of small, local nuclear-spin ensembles. These results establish SQUINT as a framework for quantum sensing that provides molecular-level control over sensor properties and allows direct integration with complex molecular targets.