Design concepts in absorbance optical systems for analytical ultracentrifugation

Analytical ultracentrifugation is a powerful technique for analyzing particles in solution, and has proved valuable for a wide range of applications in chemistry, biochemistry and material sciences for many years. The field is presently seeing a resurgence of instrument development from commercial and academic groups. To date, no modern optical modeling techniques have ever been applied to the basic imaging properties of the optical system in analytical ultracentrifugation. In this manuscript we provide a contextual framework for the application of such techniques, including an overview of the essential optical principles. The existing commercial and open source detection systems are evaluated for imaging performance, highlighting the limitations of chromatic aberration for broadband acquisitions. These results are the inspiration for a new mirror-based design, free of chromatic aberration. Our findings present a path forward for continued development in imaging and detector technology, where improved data quality will now push the limits of detection and resolution of analytical ultracentrifugation for years to come.