InGaAsP photonic crystal slot nanobeam waveguides for refractive index sensing

Abstract

Results are presented on the use of InGaAsP photonic crystal nanobeam slot waveguides for refractive index sensing. These sensors are read remote-optically through photoluminescence, which is generated by built-in InGaAs quantum dots. The nanobeams are designed to maximize the electromagnetic field intensity in the slot region, which resulted in record-high sensitivities in the order of 700 nm/RIU (refractive index unit). A cavity, created by locally deflecting the two beams towards each other through overetching, is shown to improve the sensitivity by about 20%.