Optical scatter from non-uniform molecular films

Particle-induced light scatter reduces sensitivity and degrades performance of optical systems. Though particles are generally considered to be the primary source responsible for stray radiation, there is evidence that molecular contaminants also induce light scatter. The primary objective for this research effort has been to increase our understanding of molecular contaminant film growth and its implications for light scatter. Herein, our new molecular film deposition and imaging facility is described. In-situ imaging data, acquired from non-uniform films of contaminant analogues, has revealed that even small quantities (less than 100 angstrom mass equivalent) of molecular contamination can produce scattered light. These data suggest that small amounts of molecular contamination have the potential to significantly impact the performance of scatter sensitive optical systems.