Imaging with a 90frames∕s microbolometer focal plane array and high-power terahertz free electron laser

Abstract

An uncooled microbolometer focal plane array (FPA) has been developed and used for imaging of objects illuminated by monochromatic coherent radiation of a free electron laser tunable in the range of 1.25–2.5THz. A sensitivity threshold of 1.3×10−3W∕cm2 was obtained for the FPA with a homemade absolute interferometric power meter. Videos up to 90frames∕s were recorded in both transmission and reflection/scattering modes. When objects were illuminated by laser radiation scattered by a rough metal surface, speckled images were observed. Good quality terahertz images were achieved through the fast rotation of the scatterer.