Polarization compensation of Fresnel aberrations in telescopes

Abstract

Large aperture space telescopes are built with low F#'s to accommodate the mechanical constraints of launch vehicles and to reduce resonance frequencies of the on-orbit system. Inherent with these low F# is Fresnel polarization which effects image quality. We present the design and modeling of a nano-structure consisting of birefringent layers. Analysis shows a device that functions across a 400nm bandwidth tunable from 300nm to 1200nm. This Fresnel compensator device has a cross leakage of less than 0.001 retardance.