Design of a trap-assisted exceptional-surface-enhanced silicon-on-insulator particle sensor

Due to the recent interest in nanoparticles for both new functionalities and health-and-environment risks-related particle emissions of vehicles and industries, integrated-photonic single-particle sensors are urgently required. Exceptional surfaces (ESs) have been demonstrated to enhance the sensitivity of optical sensors and particle sensing is one of the most promising applications of ESs. The aim of this work is to show an ES-based architecture suitable for sensing the presence of nanoparticles with the aid of particle trapping allowed by optical forces. The solution proposed here enables the particle sensing with a passive architecture on an SOI chip. In this work it is shown that an SOI slot-waveguide-based ring-resonator architecture can be used for sub-50 nm single-particle sensing. Moreover, with a thermo-optic modulator we demonstrate that it is possible to measure the size of the particle, independently of its position along the ring resonator, with robustness to parameter fluctuations and noise.