All-Dielectric Metasurface Refractive Index Sensor with Microfluidics

Magnetic resonance and electrical resonance can be excited simultaneously by the incident light source in high refractive index all-dielectric metasurfaces. They can manipulate light waves to a certain extent and can be used in many fields. Silicon is widely used in all-dielectric metasurfaces due to its high refractive index and low loss in near infrared range. In this paper, we use silicon nanodisk structure as refractive index sensor and PDMS microfluidic channels as detection channels to realize liquid refractive index sensing. The magnetic resonance peak of the nanodisk structure is selected for sensing. The position of the magnetic resonance is shifted in the transmission spectrum with the change of the refractive index of the surrounding environment. When the refractive index increases, the resonance peak moves towards the long-wave direction, resulting in red shift, and vice versa. In this paper, the shift of resonance peak reaches 230 nm RIU⁻¹. (paper)