Fabrication of Thin-Film Fresnel Optics by Combining Diamond Turning and Photolithographic Processes
Jiwang Yan*, Kenta Watanabe**, and Yutaro Nakagawa**
*Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
**Department of Mechanical Systems and Design, Graduate School of Engineering, Tohoku University, 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
A novel fabrication process is proposed for manufacturing thin-film metal Fresnel lenses for X-ray applications. This process combines diamond turning technology and photolithographic processes. To prevent thin-film lens substrates from deflection during diamond turning, films were prepared on single crystalline silicon wafers by electrolytic plating. After the Fresnel lens structure is generated on the metal thin films by diamond turning, the silicon substrate was then removed selectively by reactive ion etching. Experimental results demonstrated that the proposed hybrid fabrication process achieves submicron form accuracy and nanometer surface roughness.
-  G. K. Skinner, “Diffractive/refractive optics for high energy astronomy, I. Gamma-ray phase Fresnel lenses,” Astronomy & Astrophysics, Vol.375, pp. 691-700, 2001.
-  G. K. Skinner, Z. Arzoumanian, W. C. Cash, N. Gehrels, K. C. Gendreau, P. Gorenstein, J. F. Krizmanic, M. C. Miller, J. D. Phillips, R. D. Reasenberg, C. S., Reynolds, R. M. Sambruna, R. E. Streitmatter, and D. L. Windt, “The Milli-Arc-Second Structure Imager, MASSIM: A new concept for a high angular resolution X-ray telescope, Space Telescopes and Instrumentation 2008: Ultraviolet to Gamma Ray,” M. J. L. Turner and K. A. Flanagan (Eds.), Proc. of SPIE, Vol.7011, 70110T, 2008.
-  J. Yan, K. Maekawa, J. Tamaki, and T. Kuriyagawa, “Micro grooving on single-crystal germanium for infrared Fresnel lenses,” J. of Micromechanics and Microengineering, Vol.15, No.10, pp. 1925-1931, 2005.