Ring grating-nanoprism structure for efficient focusing of surface plasmon polaritons

Abstract : This work aims to study light-matter interaction at the nanoscale by integrating emitters with plasmonic structures. Our proposed structure consists of metallic nanoprisms in the center of ring diffraction gratings. Surface plasmon polaritons (SPPs) are generated by the ring grating which propagate and get focused on the nanoprism tip forming an intense electromagnetic hotspot in the region. FDTD numerical simulations are done to calculate the optimized angle of incidence needed for SPP excitation by the ring grating. Sample fabrication and optical characterization methods are presented to study the coupling between generated SPPs and CdSe quantum dots placed in the center. FDTD simulations as well as experimental observations are done to study the electromagnetic hotspot at the tip of the ring gratingnanoprism structure. This work will be extended further to include the coupling between SPPs and emitters placed in the hotspot which leads to their photoluminescence and lifetime enhancement.