197 / 2024-07-10 15:13:41

Controlling Periodic Fano Resonances in a Violet Phosphorus-Based Plasmonic Waveguide

Periodic Fano Resonances, Violet Phosphorus, Resonance Periods, Energy Level Splitting

Nanoscale Fano resonances usually oberved in a host of plasmonic waveguides, have great promising in designing various optoelectronic devices. Unlike other two allotropes of phosphorus (black/blue phosphrous, BP/Blue-P), violet phosphorus (VP) has shown a high refractive index (RI) and low loss in the visble–NIR regime, indicating it is a potential candidate for creating novel Fano resonance waveguides. In this work, we theoretically proposed a novel periodic Fano resonance waveguide by controlling the thickness of VP film. The plasmonic waveguide was designed by simply stacking VP film onto a SiO₂-Ag hybrid configuration. Interestingly, the periodic Fano Resonances can be produced by varying the thickness of VP films. Typically, it have two stable Fano Resonance periods including a smaller period (110-120 nm) and a larger period (1150-1250 nm). In a smaller period, the periodic Fano Resonance signals can be reappeared by introducing every VP nanossheets with a thickness of 117 nm. However, in a larger period, the energy level splitting can be generated by adding every VP nanossheets with a thickness of 1200 nm. In addition, the coupling mechanism between VP film and SiO₂-Ag hybrid configuration was systematically calculted. More importantly, the optimized VP-based plasmonic device can provide an ultra-high detection sensitivity of 3.61234×10⁵ μm/RIU for monitoring the local RI variations. It can be expected that, our proposed VP-based plasmonic waveguide has great potential in performing ultrasensitive biosensing applications.