Towards mass sensing using cavity optomechanics readout

The minute size of nanoelectromechanical systems (NEMS), combined with their large quality factors, has provided a large class of sensors capable of measuring the properties of single molecules. In particular, NEMS have allowed the mass of individual adsorbed molecules, such as protein complexes, to be measured. I will present results showing NEMS based mass spectrometry of individual proteins and explain how the mass resolution is governed by the phase noise of the system, with contributions from the resonator itself, readout circuitry and thermomechanical noise. I will outline our new approach based on a superconducting cavity optomechanics readout scheme for improved sensor performance. The transduction by cavity optomechanics is expected to greatly reduce system phase noise as readout-self heating is minimal. This will directly yield improved resolution in detecting the spatial mass distribution of individual analytes.