Improving the sensing performance of double gold gratings by oblique incident light

Here we demonstrate a simple method to improve the plasmonic sensing performance of gold gratings. The gratings consist of periodic polymer gratings covered with a gold layer, created by nanoimprint lithography and metal deposition. We investigated the effect of gold thickness and the incident angles on the plasmonic sensing performance. With the optimized gold layer, the full-width at half maximum of this grating was reduced by 60% by using the oblique incident light instead of the normal incident light. A maximum value of the figure of merit at oblique incidence is 12, which is double the one at normal incidence.