Polarization-Sensitive Broadband Metamaterial Absorber Based on Plasmonic Bilayer Nanostructure Array for Potential Applications in Polarization Photodetection

In this work, a broadband polarization-sensitive metamaterial absorber (MA) based on a plasmonic bilayer nanostructure array is designed and numerically investigated. The proposed polarization-sensitive MA exhibits a high average absorption of 91.9% for TM-polarized light from 500 nm to 2000 nm and as low as 11.6% for TE-polarized light. Furthermore, a plasmonic germanium photodetector (PD) functionalized by the proposed polarization-sensitive MA is constructed and the potential application of distinguishing TM- and TE-polarized light is explored in simulation. The calculated results demonstrate that the photo-current difference generated by the PD under TM- and TE-polarized light excitation can reach 11.9 μA. The proposed broadband polarization-sensitive MA can be used in many fields, including polarization detection and other polarization-sensitive optoelectronic devices.