Enhanced sensitivity SOI microring resonator with integrated one-dimensional photonic crystal
We present a silicon-on-insulator microring resonator-based refractive index sensor with enhanced sensitivity and measurement range [3]. Both improvements are achieved by integrating a 1D photonic crystal inside the microring waveguide. A photonic crystal is formed by periodically patterning, partially etching the rectangular perforations. Our findings show that, while deeper perforations result in a larger bulk refractive index sensitivity, the optimal design exhibiting the smallest limit of detection can be obtained at some intermediate value, depending on the leading term in sensor resolution. In addition to theoretical analysis, we present an experimental demonstration of a fabricated microring resonator with 120 nm height perforations.


Microring resonator with photonic crystal for refractive index sensing
Experimental and numerical analysis of a microring resonator with an integrated one-dimensional photonic crystal fabricated on a silicon-on-insulator platform shows its applicability in bulk refractive index sensing [2]. The photonic crystal was formed by periodically patterned, partially etched cylindrical perforations, whose induced photonic bandgap is narrower than the range of measurable wavelengths (1520–1620 nm). The microring operates in both air and dielectric bands, and the sensitivities of the resonances on both edges of the bandgap were investigated. Higher field localization inside the perforations for the air band mode leads to an increase in sensitivity.


Nanophotonic SOI ring sensor decorated by Au nanodiscs
A refractive index sensor based on an optical silicon-on-insulator (SOI) micro-ring resonator with a periodically arranged set of gold nanodisks, is designed [1]. Periodic arrangement of nanodisks selects a single resonance from a wide set of ring resonator modes and removes the mode splitting. Extraction of the electromagnetic energy into evanescent plasmonic modes enhances the light–analyte interaction and increases device sensitivity to variation of refractive index up to 176 nm∕RIU.

