Angularly stable terahertz multiband LiNbO3-polymer hybrid metamaterial for microfluidic refractive index sensing

Abstract

A terahertz (THz) LiNbO3-polymer hybrid metamaterial (LPHM) consisting of three-layer Au patterns and two medium interval layers is demonstrated, and the bulk refractive index (RI) sensing performance is also studied. The parameter optimizations and sensing performances of the LPHM are simulated by the finite-element method (FEM). The results show that the reflection or absorption spectrum of the LPHM has four peaks in the 1–10 THz band, and the peaks move toward the lower frequency when the period (P) of the LPHM or the side length (a) of the notched square frame increases but shift to the higher frequency when w1 or w2 increases. Moreover, the LPHM has a wide angular stability and good structural stability. The sensing performance shows that the LPHM can achieve an RI sensitivity of 11.5 µm/RIU with a detection limit (DL) of 2.9×10−4RIU. The LPHM has potential applications in pharmacological biodevices, THz immunosensing, modern medical and clinical practices, and detection of thin films and biochemical substances, and it can be expected to realize multiphysical parameter measurements.