Design and performance of a F/#-conversion microlens for Prime Focus Spectrograph at Subaru Telescope

Naruhisa Takato; Yoko Tanaka; James E. Gunn; Naoyuki Tamura; Atsushi Shimono; Hajime Sugai; Hiroshi Karoji; Akitoshi Ueda; Kouichi Waseda; Masahiko Kimura; Youichi Ohyama

doi:10.1117/12.2055051

arXiv · 1408.2867

Design and performance of a F/#-conversion microlens for Prime Focus Spectrograph at Subaru Telescope

Naruhisa Takato·Yoko Tanaka·James E. Gunn·Naoyuki Tamura·Atsushi Shimono·Hajime Sugai·Hiroshi Karoji·Akitoshi Ueda·Kouichi Waseda·Masahiko Kimura·Youichi Ohyama

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Abstract

The PFS is a multi-object spectrograph fed by 2394 fibers at the prime focus of Subaru telescope. Since the F/# at the prime focus is too fast for the spectrograph, we designed a small concave-plano negative lens to be attached to the tip of each fiber that converts the telescope beam (F/2.2) to F/2.8. We optimized the lens to maximize the number of rays that can be confined inside F/2.8 while maintaining a 1.28 magnification. The microlenses are manufactured by glass molding, and an ultra-broadband AR coating (<1.5% for lambda=0.38-1.26 um) will be applied to the front surface.

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Naruhisa Takato, Yoko Tanaka, James E. Gunn, Naoyuki Tamura, Atsushi Shimono, Hajime Sugai, Hiroshi Karoji, Akitoshi Ueda, Kouichi Waseda, Masahiko Kimura, Youichi Ohyama. 2014-08-12. Design and performance of a F/#-conversion microlens for Prime Focus Spectrograph at Subaru Telescope. https://doi.org/10.1117/12.2055051

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