A DUAL-BAND TERAHERTZ FOCAL PLANE ARRAY FOR MATERIAL COMPOSITION IDENTIFICATION BY SPECTRAL IMAGING

This paper reports a dual-band terahertz (THz) bi-material microcantilever focal plane array (FPA) for material composition identification by a spectral imaging method. To achieve the THz spectral imaging, a dual-band metamaterial absorber (MA) working at 2.52 THz and 3.11 THz was integrated into the bi-material microcantilever by introducing multiplexed Au cross resonators on a SiNx dielectric layer. The FPA works based on a photo-thermomechanical effect with the SiNx dielectric layer also as a structural layer, and an Au layer that functions both as a mirror of the bi-material microcantilever and a ground plane of the MA. Finally, THz spectral images of tablets with different ingredients, metal stripes on a polytetrafluoroethylene (PTFE) plate, and copper holes on a PCB were captured successfully with the fabricated dual-band FPA.