In-process metrology for segmented optics UV curing control

Abstract

Powerful and novel telescope design is key to pushing the available limits of astronomical sciences and a segmented primary is an attractive approach. For the Nautilus Space mission, a segmented lens has been proposed to replace large monolithic primary optics for the purpose of survey faint objects like exo-planets as well as time-domain astrophysics observations. Enabling technology for Nautilus is an ultra-lightweight multi-order diffractive engineered (MODE) lens that replaces bulky primary mirrors. The MODE lens consists of multiple, identical, molded segments. This is because the complicated optical design of both the diffractive surfaces is not easily manufacturable by traditional fabrication methods. Besides, the molding approach for identical segmented optics allows for a cost-efficient process. Conversely, the fusion of segmented optics demands high precision metrology and a delicate assembly strategy. We propose an in-process metrology technique that mitigates post-assembly process complications. This system monitors the co-phase character of the segmented optics during UV cured assembly, guiding the overall process.