A Longwave Infrared Focal Plane Array Enhanced by Backside-Configured Plasmonic Structures

We demonstrate a 320 × 256 longwave infrared focal plane array (FPA) enhanced by backside-configured surface plasmonic structures. The backside-configured plasmonic structures were fabricated on the photodetector side rather than the substrate side. The backside plasmonic FPA shows an average noise-equivalent temperature difference (NEΔT) of 110 mK with a standard deviation σ of 11.09 mK at the blackbody temperature of 30°C. Over 50% improvement in NEΔT is obtained by the backside plasmonic structures. Since the backside configured plasmonic structures can be fabricated on the photodetector side before the substrate lapping and removing, the difficulty of fabricating a plasmonic FPA is greatly reduced.