Development Of Nanostructured Antireflection Coatings For Infrared Image Sensing Technologies

Image sensing technologies and systems operating from the ultraviolet (UV) to long-wave infrared (LWIR) spectral range are being developed for a variety of defense and commercial systems applications. Reflection loss of a significant portion of the incident signal limits the performance of image sensing systems. One of the critical technologies that will overcome this limitation and enhance image sensor performance is the development of advanced antireflection (AR) coatings. In this paper, we review our latest work on high-quality nanostructure-based AR structures, including recent efforts to deposit nanostructured AR coatings on substrates transparent to infrared (IR) radiation. Nanostructured AR coatings fabricated via a scalable self-assembly process are shown to enhance the optical transmission through transparent optical components by minimizing reflection losses in the spectral band of interest to less than one percent, a substantial improvement over conventional thin-film AR coating technologies. Step-graded AR structures also exhibit excellent omnidirectional performance, and have recently been demonstrated in medium wavelength and long wavelength IR spectral bands.