Label-free detection of ambient refractive index based on plasmonic Bragg gratings embedded resonator cavity sensor

In this work, we incorporated Bragg gratings in the standard ring resonator design in order to enhance the sensitivity of the refractive index sensor. The transmission spectrum and electric field distribution of the device are simulated using the finite element method (FEM). The numerical simulation results obtained from the transmission spectrum are used to examine the sensing characteristics of the structure. The size of the grating teeth has a significant effect on the intensification of surface plasmons which in turns enhances the interaction between the ambient medium and the light. Bragg grating embedded resonator cavity design has the best sensitivity, FOM and Q-factor of 1680 nm/RIU, 48 and 48.4, respectively which is much higher than several previously reported values.