Co-phase detection of segmented mirrors based on optical vortex polarization phase-shifting interference

Abstract

The imaging performance of segmented optical telescopes depends on the positional assembly accuracy of segmented mirrors. In this paper, we present a novel method for measuring the piston and tip/tilt errors of segmented mirrors based on optical vortex polarization phase-shifting interferometry. The functional relationships between piston error or tip/tilt error and phase distribution in the image plane are derived. To validate the correctness of the relationships, we established an optical system model in the non-sequential mode of OpticStudio. The phase information is acquired by the least squares method as well as the Hough transform, whereby the piston or tip/tilt errors can be retrieved by the functional relationships. The results of simulations and experiments validated the feasibility of the proposed method. It shows excellent efficiency because the analysis process is computationally non-intensive. The method has an extended measurement range and high accuracy, bypassing the demanding hardware requirements and providing a novel approach for measuring co-phase errors in a segmented primary mirror.