New candidate substrate materials for space mirror optics

Hsing-Yu Wu; Wei-Che Chang; Po-Hsuan Huang; Yi-Kai Huang

doi:10.1117/12.2530689

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30 August 2019 New candidate substrate materials for space mirror optics

Hsing-Yu Wu, Wei-Che Chang, Po-Hsuan Huang, Yi-Kai Huang

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Proceedings Volume 11101, Material Technologies and Applications to Optics, Structures, Components, and Sub-Systems IV; 111010L (2019) https://doi.org/10.1117/12.2530689
Event: SPIE Optical Engineering + Applications, 2019, San Diego, California, United States

Abstract

This paper describes superior candidate substrate material- aluminum nitride (AlN), for the cost-effective and high-performance requirements for aerospace mirrors. In fact, high specific stiffness and thermal stability are not only two major considerations to select ideal material but also machinability, dimensional stability, and cost. Silicon carbide shows the best figure of merits 12627, but it has extremely low remove rate and expensive raw material properties. Extremely low expansion ceramics such as Zerodur may be difficult to obtain in large quantities and its figure of merit is 1151. On the contrary, AlN has outstanding thermal conductivity (~170 W/m°C) and maintain high figure of merit 2222 without compromise. In our fabrication processes, the AlN substrate can be easily polished to 53±1nm Ra surface texture and 66.4±2nm RMS surface form. Its unique thermal stability, specific stiffness, and good figure of merits, associated with its easy machinability and low-cost raw materials, makes AlN an ideal selection for superior mirror substrate in the future space mirror optics.

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Hsing-Yu Wu, Wei-Che Chang, Po-Hsuan Huang, and Yi-Kai Huang "New candidate substrate materials for space mirror optics", Proc. SPIE 11101, Material Technologies and Applications to Optics, Structures, Components, and Sub-Systems IV, 111010L (30 August 2019); https://doi.org/10.1117/12.2530689

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