Sensor sensitivity and synchronization induced by exceptional point in optomechanical systems

We propose an efficient optomechanical mass sensor operating at exceptional points (EPs), non-Hermitian degeneracies where eigenvalues of a system and their corresponding eigenvectors simultaneously coalesce. It consists of two optomechanical cavities that are coupled mechanically. The cavity is driving by a blue-detuned (red-detuned) laser to control the gain loss. At the gain and loss balance, an EP is observed where any perturbation induces a frequency splitting resulting in a giant sensitivity-factor enhancement compared with conventional optomechanical sensors. This work paves the way toward new levels of sensitivity for optomechanical sensors, which could find applications in many other fields, including nanoparticle detection, precision measurement, and quantum metrology.