Schottky-type surface plasmon detector with nano-slit grating using enhanced resonant optical transmission

Abstract

We propose a metal nano-slit structure to enhance the surface plasmon (SP) intensity at the Au/Si interface between a gold film and a silicon substrate. By tuning the phase conditions to be in anti-phase interference at the air/Au interface and in in-phase interference at the Au/Si interface, the SP intensity at the Au/Si interface was enhanced. This structure was numerically designed using the finite-difference time-domain method and was experimentally confirmed by monitoring of the photocurrent of an Au/Si Schottky-type SP detector. This design, with its two phase matching conditions that enhance the SP intensity at the Au/Si interface, was applied to a ring-type metal grating on a silicon substrate, and demonstrated the photocurrent enhancement.