High-performance double-layer phase SPR sensor based on film thickness optimization

With an emphasis on phase interrogation, the study demonstrated a Ag-Au bilayer film surface plasmon resonance (SPR) sensor. Initially, the bimetallic sensor's silver and gold layer thicknesses were changed to maximize the phase difference at the resonance angle. The scientists then used ideal silver-gold thicknesses to investigate the sensitivity of SPR sensors. The SPR sensor's sensitivity decreases with a larger Ag layer in the bilayer film, indicating that bimetallic sensors may be more sensitive than single-layer ones. Additionally, by studying the electric field inside the bimetallic sensor, we investigated the basic physics underlying its improved performance.