Multi-target detection and sizing of single nanoparticles using an optical star polygon microcavity

Abstract

We present a miniaturized single nanoparticle detector that utilizes an optical star polygon microcavity with a 3 µm-radius. The microcavity supports high-quality factor resonant modes, with light localized at the corners of the star-shaped polygon, where the air region is situated. When nanoparticles are positioned at the corners of the microcavity, the light-matter interactions are enhanced. Notably, increasing the number of particles has little effect on the quality factor of the cavity, making it ideal for the simultaneous detection of multiple targets. Our numerical simulations demonstrate the high precision detection of polystyrene nanoparticles with a radius of 3 nm using this method. Furthermore, the size and number of nanoparticles can be determined by utilizing the triangular corners of the cavity as rulers. These findings represent a significant advancement in miniaturized and multi-target simultaneous nanoparticle detection. The proposed detector is expected to have a wide range of applications in various fields, including biomedicine and environmental monitoring.