Numerical simulations of double nanograting based plasmonic photodetector for enhancement in light absorption

This era of high-speed photonic system demands photodetectors with large bandwidth, gain and improved light enhancement competence. Amongst the different light absorption enhancement methods being researched by the investigators, plasmonic has acquired increased attention in the last decades. Although single-layer plasmonic supported metal semiconductor metal photodetector has been explored for higher light absorption efficiency, exploration for double-layer structure is lacking in the literature. This paper presents the performance of plasmonic-based photodetectors with double layer of nanogratings optimized at a wavelength of 1.4 µm for night vision applications. Proposed design of plasmonic supported photodetector with double nanograting reports quenching factor of 92.14% and provides an enhancement in light with the optimized height of subwavelength aperture at 60 nm. This can be credited to fact that both the top and bottom layer of grating contribute to light trapping.