Confined Gaussian-distributed electromagnetic field of tin(II) chloride-sensitized surface-enhanced Raman scattering (SERS) optical fiber probe: From localized surface plasmon resonance (LSPR) to waveguide propagation.

Surface-enhanced Raman scattering (SERS) induced by largely enhanced electromagnetic (EM) field provides a solid and promising avenue for ultrasensitive molecular detection. Here, a confined Gaussian-distributed EM field for SERS fiber probe with two influencing factors (localized surface plasmon resonance (LSPR) of silver and waveguide propagation of optical fiber) are proposed for the first time. SERS fiber probes with high sensitivity and good reproducibility were synthesized via a novel SnCl sensitization aided solvothermal method.

Investigation on single taper-based all-solid photonic bandgap fiber modal interferometers.

We demonstrate a single taper-based all-solid photonic bandgap (AS-PBG) fiber modal interferometer that consists of a central tapered fiber region connected to the untapered via two abrupt transitions. Modal interference is given by superimposing the bandgap-guided fundamental core mode with a lower effective index and a specific index-guided cladding supermode with a higher effective index. A series of interferometers with taper diameter of 50μm ~60μm and device length of ~3mm are fabricated and studied in contrast to the conventional counterparts.