A Dual-Parameter Interrogation Fano Resonance Sensor Based on All-Oxide Multilayer Film for Biomolecule Detection

We present an innovative Fano resonance sensor based on an all-oxide multilayer film for biomolecule detection. The sensor, consisting of a rutile prism, indium tin oxide (ITO), SiO2, and TiO2 layers, employs a Kretschmann configuration to induce Fano resonance. The sensor features a straightforward structure, economical cost, strong stability, compatibility with CMOS processes, and excellent biological affinity. The sensor is produced by a multitarget magnetron sputtering technique in one go, which streamlines the process, minimizes material and energy waste, and is appropriate for large-scale industrial manufacturing. The sensor functioning in the near-infrared spectrum exhibits less photodamage and phototoxicity to living biological materials, rendering it optimal for real-time monitoring of the dynamic processes within living cells in biological and medical applications. The sensor provides dual-parameter measuring capabilities, encompassing wavelength and phase interrogation, attaining high sensitivity (656 nm/RIU and $2.6\times 10^{{5}}~^{\circ }$ /RIU) and a figure of merit (FOM) of 1093. Experimental results indicate the sensor’s effectiveness in identifying biomolecules with exceptional real-time detection capability and superior selectivity. This work advances Fano resonance sensors from theory to practical applications, serves as a reference for designing high-sensitivity sensors, and expands their potential application in chemical analysis, medical diagnostics, and environmental monitoring.