Analysis and quantification of laser-dazzling effects on IR focal plane arrays

Today Optronic Countermeasure (OCM) concerns imply an IR Focal-Plane Array (FPA) facing an in-band laser irradiation. In order to evaluate the efficiency of new countermeasure concepts or the robustness of FPAs, it is necessary to quantify the whole interaction effects. Even though some studies in the open literature show the vulnerability of imaging systems to laser dazzling, the diversity of analysis criteria employed does not allow the results of these studies to be correlated. Therefore, we focus our effort on the definition of common sensor figures of merit adapted to laser OCM studies. In this paper, two investigation levels are presented: the first one for analyzing the local nonlinear photocell response and the second one for quantifying the whole dazzling impact on image. The first study gives interesting results on InSb photocell behaviors when irradiated by a picosecond MWIR laser. With an increasing irradiance, four different successive responses appear: from linear, logarithmic, decreasing ones to permanent linear offset response. In the second study, our quantifying tools are described and their successful implementation through the picosecond laser-dazzling characterization of an InSb FPA is assessed.