Polarization-selective uncooled infrared sensor with asymmetric two- dimensional plasmonic absorber

A polarization-selective uncooled infrared (IR) sensor was developed based on an asymmetric twodimensional plasmonic absorber (2-D PLA). The 2-D PLA has an Au-based 2-D periodic dimple structure, where photons can be manipulated by spoof surface plasmon polaritons. Asymmetry was introduced into the 2-D PLA to realize a polarization selective function. Numerical investigations demonstrate that a 2-D PLA with ellipsoidal dimples (2-D PLA-E) gives rise to polarization-dependent absorption properties due to the asymmetric dimple shape. A microelectromechanical systems-based uncooled IR sensor was fabricated using a 2-D PLA-E through complementary metal oxide semiconductor (CMOS) and micromachining techniques. The 2-D PLA-E was formed with an Au layer sputtered on a SiO2 layer with ellipsoidal holes. The dependence of the responsivity on the polarization indicates that the responsivity is selectively enhanced according to the polarization and the asymmetry of the ellipsoids. The results provide direct evidence that a polarization-selective uncooled IR sensor can be realized simply by the introduction of asymmetry to the surface structure of the 2-D PLA, without the need for a polarizer or optical resonant structures. In addition, a pixel array where each pixel has a different detection polarization could be developed for polarimetric imaging using standard CMOS and micromachining techniques. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.OE.53.10.107110]