Phase Defect Modeling and Testing

Abstract

An anomalous phase defect has been observed in a particular type of broadband coating which exhibits a dispersive effect on transmitted imagery, decreasing the perceived contrast at specific wavelengths. This paper provides an overview of coating methods and technology with potential sources of defects and outlines the development of a physical optics defect model based on observed spectral data. Model results are then used to investigate the impact of defect size and position on an image transmitted through the coating as a function of wavelength. Lastly, an overview of a proposed laboratory window screening method is provided, which will screen a coated spare window filter for the presence of defects.