A Compact Device of Optical Fiber Taper Coupled Monolayer Silver Nanoparticles for Raman Enhancement

A compact surface-enhanced Raman scattering (SERS) device has been developed, which comprises a monolayer silver nanoparticle substrate and an optical fiber taper. The analysis of cavity modes in both plasmonic and dielectric resonators offers valuable insights into the light-matter interactions. To rigorously determine field enhancement factors, Purcell factors, effective mode volumes, and quality factors, we employed classical and quasi-normal mode (QNM) calculations. By using a simplified silver spherical dimer as an example, we were able to establish connections between simulation, theoretical calculation, and experimental results. Furthermore, we investigated the directional antenna (DA) effect of the fiber taper. Our research lays the foundation for further exploration of "resonance," "leaky nature," "quasimode," and "antenna radiation" phenomena in realistic situations.