Angular-dependent photodetection enhancement by a metallic circular disk optical antenna

In this paper, we analyze the plasmonic resonance excited by linearly polarized long-wave infrared (LWIR) planewaves in a metallic circular disk optical antenna(MCDA). The surface current distributions are simulated at different wavelengths, incident angles, and polarizations. The excited surface plasmonic resonance waves (SPRs) are different from the Bessel-type of SPR modes and closely resemble those in a monopole antenna. An MCDA coupled LWIR quantum dot infrared photodetector (QDIP) was fabricated and measured at different LWIR plane wave wavelengths and incident angles. A linear correlation between the enhancement ratio and the integrated square of the current is obtained, indicating the monopole antenna effect is a dominating factor for the plasmonic enhancement. (C) 2017 Author(s).