Polarization insensitive perfect absorber with nanorod arrays

We propose a polarization insensitive near infrared perfect absorber (PA) based on the localized surface plasmon resonances (LSPRs) of nanorod arrays. Polarization insensitivity of our PA structure is achieved by combining two sets of nanorods with x and y orientation respectively. Study carried out by finite difference time domain (FDTD) method shows absorption rate and the peak wavelength are sensitive to the lattice period both in x and y directions. The nanorods resonance is only slightly impacted by nanorods on its vertical direction. Further research into multiband polarization-insensitive absorber can be expected base on this work.