Liquid Metal-Based Continuously Tunable Surface Plasmon Resonator for Lab-on-Chip Sensor Applications

Metamaterials have been extensively utilized in diverse applications, including invisibility cloaks, superlenses, highly efficient environmental sensors, and others. However, for resonant metamaterial structures based on traditional solid metallic materials, the resonance property is usually nonadjustable once the structure is manufactured. To improve the flexibility and enhance the electromagnetic response of metamaterial, we propose and demonstrate a low-cost, continuously tunable surface plasmon resonator (CTSPR) based on liquid metal and lab-on-chip technology. By appropriately tailoring the number of laps and peripheral radius of the spiral arms in constructing the CTSPR, the tuning range of resonance frequency reaches 1.8 GHz (from 0.36 GHz to 2.16 GHz). The potential application of the resonator in biosensing and temperature-sensing has been experimentally examined. Furthermore, the CTSPR is feasibly employed in flexible sensors, enabling its utilization in a diverse range of detection scenarios. Due to the separable design of the CTSPR sensor and its biocompatibility, the CTSPR is envisioned to be implanted
in vivo
, with the excitation source positioned externally.