Stress mirror polishing for future large lightweight mirrors: design using shape optimization

Area of Science:

• Optical engineering
• Materials science
• Manufacturing technology

Background:

• Space telescopes require large, lightweight aspheric optics for advanced imaging.
• Traditional methods for aspheric surface generation are often time-consuming and complex.
• Stress Mirror Polishing (SMP) offers a potentially faster route to high-quality optical surfaces.

Purpose of the Study:

• To present a new manufacturing approach for large lightweight aspherics using SMP.
• To detail the process of determining optimal mirror thickness distribution for aspherization.
• To demonstrate the feasibility of generating specific aspheric shapes via thickness reshaping.

Main Methods:

• Introduction to active optics and Stress Mirror Polishing (SMP) principles.
• Development of a process for calculating required mirror thickness distribution.
• Implementation of a shape optimization procedure using Python and NASTRAN finite element analysis (FEM).

Main Results:

• The shape optimization process effectively supports SMP in generating peculiar aspheric shapes.
• A specific aspherical shape can be achieved from a spherical optical surface through thickness distribution reshaping.
• Numerical simulations confirm the theoretical framework's viability.

Conclusions:

• The proposed theoretical framework and numerical simulations provide a viable first step towards manufacturing demonstrators.
• This two-step approach, combining thickness optimization with SMP, is a promising technique for aspheric optic production.
• The method enables the creation of complex aspheric surfaces with high precision and efficiency.