An integrated hybrid waveguide coupled long range surface plasmon polaritons (LRSPPs) biosensor is
proposed and analyzed by the Finite Element Method (FEM). The influence of the structural parameters on the
coupling between the dielectric waveguide (DWG) and LRSPPs modes are numerically investigated.
Simulation results show that the resonant coupling wavelength between the DWG and LRSPPs modes is very
sensitive to small refractive index changes i.e. the estimated sensitivity is as high as 4180 nm/RIU (refractive
index unit). Furthermore, when operating in intensity interrogation, its detection of limit has been shown as
small as 3.7 x 10-7 RIU.
A novel plasmonic biosensor based on coupled metal-dielectric buffer grating is proposed and analyzed by the rigorous
coupled wave analysis (RCWA) method. The metal-dielectric buffer grating structure offers surface plasmon resonance
suitable for high sensitivity biosensing applications. The calculated FWHW (full width at half maximum) of the
transmission peak is 5 nm and the optical transmission efficiency is significantly enhanced at the resonant wavelength of
800.8 nm by introducing the dielectric buffer grating. The highly concentrated field distribution is sensitive to
surrounding refractive index changes of the metal surface providing a sensitivity of 560 nm/RIU (refractive index unit)
for optical biosensing applications.
An enhanced refractive index (RI) sensor with combination of long period fiber grating (LPG) and a small core
singlemode fiber (SCSMF) structure is proposed and developed. Since the LPG and SCSMF transmission spectra
experience a blue and red shift respectively as the surrounding RI (SRI) increases, the sensitivity is improved by
measuring the separation between the resonant wavelengths of the LPG and SCSMF structures. Experimental results
show that the sensor has a sensitivity of 1028 nm/SRI unit in the SRI range from 1.422 to 1.429, which is higher than
individual sensitivities of either structure alone used in the experiment.
In this paper, a novel T-shaped plasmonic metal-insulator-metal (MIM) splitter with one input and two outputs is
proposed, which uses simple stacked Bragg reflectors placed on both the left and right branches. Simulation results
show that the resonance wavelengths of the surface plasmon polaritons (SPPs) can be effectively controlled and
guided along the desired direction with high confinement by properly designing the parameters of the structure, such
as the refractive index of the dielectric, the period and the number of dielectric modulations N. Moreover, the splitting
ratio is found to be adjustable by tuning the value of N.