Photonic crystal slot nanobeam slow light waveguides for refractive index sensing

We present the design, fabrication, and photoluminescence experiment of InGaAsP photonic crystal slot nanobeam slow light waveguides with embedded InAs quantum dots. The strong confinement of electric field in the slot region is confirmed by the measured record high sensitivity of 7×102 nm per refractive index unit (RIU) to the refractive index change of the environment. A cavity, formed by locally deflecting the two beams toward each other, gives an even higher sensitivity of about 9×102 nm/RIU