Development of electro-optical characterization test bench for high performance infrared focal plane area array detectors

Infrared (IR) detection in wavelength ranging from 3µm to 18µm has been a subject of extensive research due to its key role in commercial, defense and space applications. Infrared detectors require cryogenic cooling for their operation. First generation IR imaging systems used discrete element detectors operating in whiskbroom scanning mode from geostationary platform. Due to very less interconnections and slow readout rates, these detectors can be easily characterized in lab vacuum Dewars using standard instrumentation. Second and third generation imaging systems use area array infrared detectors coupled with high performance read-out-integrated circuits (ROICs), known as focal plane array (FPA), to image wider areas at faster imaging rates [1]. In terrestrial applications, to facilitate characterization of large array IR detectors, an Integrated Detector Dewar Cooler Assembly (IDDCA) is essential whereby the FPA sits over the cold tip of an active cryo-cooler and the detector cooler assembly is vacuum sealed in a thermally isolated Dewar. Before integrating the FPA with cooler, the FPA needs to be characterized separately for assessing its usability in the imaging system. This imposes challenges for test engineers to develop an FPA characterization test bench meeting the operational requirements and testing of FPAs at cryogenic temperatures. This paper gives design details of an indigenously developed test bench to characterize electro-optical performance of infrared FPAs.