Open AccessEffects of the cone angle on the SERS detection sensitivity of tapered fiber probes
Author(s) -
Yanyan Qin,
RuiDong Huang,
Fengya Lu,
Haibin Tang,
Bo Yao,
Qinghe Mao
Publication year - 2022
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.471597
Subject(s) - materials science , optics , ligand cone angle , fiber , optical fiber , sensitivity (control systems) , refractive index , fiber laser , acceptance angle , laser , scattering , raman scattering , optoelectronics , raman spectroscopy , physics , conical surface , electronic engineering , composite material , engineering
In this paper, we investigate the effects of taper angle on the SERS detection sensitivity using tapered fiber probes with single-layer uniform gold spherical nanoparticles (GSNs). We show that the photothermal damage caused by excessive excitation laser power is the main factor that restricts the improvement of detection sensitivity of tapered fiber probes. Only when the cone angle is appropriate can a balance be achieved between increasing the excitation laser power and suppression of the transmission and scattering losses of the nanoparticles on the tapered fiber surface, thereby obtaining the best SERS detection sensitivity. Furthermore, the optimal cone angle depends on the complex refractive index of the equivalent composite dielectric (ECD) layer containing GSNs. For three SERS fiber probes with different ECD layers, the optimal cone angles measured are between 11-13°.