Current Optics and Photonics

Optical Society of Korea (한국광학회)
권호 표지
DOI QR코드

DOI QR Code

Design and Manufacture of an Off-axis Aluminum Mirror for Visible-light Imaging

  • Zhang, Jizhen (Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science) ;
  • Zhang, Xin (Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science) ;
  • Tan, Shuanglong (Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science) ;
  • Xie, Xiaolin (Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science)
  • Received : 2016.10.22
  • Accepted : 2017.06.27
  • Published : 2017.08.25
Download PDF
⟨ Previous Next ⟩

Abstract

Compared to one made of glass, an aluminum mirror features light weight, compact design, low cost, and quick manufacturing. Reflective mirrors and supporting structures can be made from the same material, to improve the athermal performance of the system. With the rapid development of ultraprecise machining technologies, the field of applications for aluminum mirrors has been developed rapidly. However, most of them are rotationally symmetric in shape, and are used for infrared applications. In this paper, the design and manufacture of an off-axis aluminum mirror used for a three-mirror-anastigmat (TMA) optical system at visible wavelengths is presented. An optimized, lightweight design provides a weight reduction of more than 40%, while the surface deformation caused by earth's gravity can meet the required tolerance. The two pieces of an off-axis mirror can be diamond-turned simultaneously in one setup. The centrifugal deformation of the off-axis mirror during single-point diamond turning (SPDT) is simulated through the finite-element method (FEM). The techniques used to overcome centrifugal deformation are thoroughly described in this paper, and the surface error is reduced to about 1% of the original value. After post-polishing, the form error is $1/30{\lambda}$ RMS and the surface roughness is better than 5 nm Ra, which can meet the requirements for visible-light imaging.

Keywords

References

  1. D. Vukobratovich and J. P. Schaefer, "Large stable aluminum optics for aerospace applications," Proc. SPIE 8125, 81250T (2011).
  2. P. S. Carlin, "Lightweight mirror systems for spacecraft - an overview of materials & manufacturing needs," in Proc. 2000 IEEE Aerospace Conf., pp. 169-181.
  3. J. J. Guregian, J. W. Pepi, M. Schwalm, and F. Azad, "Material trades for reflective optics from a systems engineering perspective," Proc. SPIE 5179, 85-96 (2003).
  4. R. Steinkopf, A. Gebhardt, S. Scheiding, M. Rohde, O. Stenzel, S. Gliech, V. Giggel, H. Loscher, G. Ullrich, P. Rucks, A. Duparre, S. Risse, R. Eberhardt, and A. Tunnermann, "Metal mirrors with excellent figure and roughness," Proc. SPIE 7102, 71020C (2008).
  5. T. H. Jamieson, "Athermalization of optical instruments from the optomechanical viewpoint," Proc. SPIE CR 43, 131-159 (1992).
  6. D. Sampath, A. Akerstrom, M. Barry, J. Guregian, M. Schwalm, and V. Ugolini, "The WISE telescope and scanner: design choices and hardware results," Proc. SPIE 7796, 779609 (2010).
  7. S. Risse, A. Gebhardta, C. Damma, T. Peschela, W. Stockla, T. Feigla, S. Kirschsteinb, R. Eberhardta, N. Kaisera, and A. Tunnermanna, "Novel TMA telescope based on ultra precise metal mirrors," Proc. SPIE 7010, 701016 (2008).
  8. L. Clermont, Y. Stockman, W. Dierckx, and J. Loicq, "Comparison of off-axis TMA and FMA telescopes optimized over different fields of view: applications to Earth observation," Proc. SPIE 9131, 91310N (2014).
  9. F. Lei, Z. Yongzhi, and C. Yuyan, "Design and analysis of metal mirror for infrared off-axial system," Infrared Technol. 37, 374-379 (2015).
  10. M. N. Sweeney, "Advanced manufacturing technologies for light-weight post-polished snap-together reflective optical system designs," Proc. SPIE 4771, 144 (2002).
  11. S. Risse, A. Gebhardt, R. Steinkopf, and V. Giggel, "NiP plates mirrors for astronomy and space," in Proc. of the 7th EUSPEN (Bremen Congress Centre, German, May. 2007), pp. 348-351.