Exceptional Point Enhances Sensitivity of Optomechanical Mass Sensors

Mass sensors are actively used to detect biomolecules, viruses, and other nano-objects, and improved sensitivity is always sought. Owing to progress in nanofabrication technology, mechanically coupled optomechanical cavities featuring exceptional points (EPs) can be engineered. The authors propose an efficient optomechanical mass sensor operating at an EP, where any perturbation induces a frequency splitting that scales as the square root of the perturbation strength, resulting in giant sensitivity enhancement. These refined optomechanical sensors could see applications in many fields, including nanoparticle detection, precision measurement, and quantum metrology.