Absolute test needs test part rotation to separate errors of the interferometer itself from errors due to the test surfaces. At this time, previous absolute test algorithms assume no azimuthal position error during part rotation. For large optics whose diameters are 0.6 m and over, however, exact rotations are physically difficult. Motivated by this, we propose a new algorithm that adopts least squares technique to determine the true azimuthal positions of part rotation and consequently eliminates testing errors caused by rotation inaccuracy.
© 2006 Optical Society of America
Wavefront measurement interferometry at the operational wavelength of extreme-ultraviolet lithography
Yucong Zhu, Katsumi Sugisaki, Masashi Okada, Katsura Otaki, Zhiqiang Liu, Jun Kawakami, Mikihiko Ishii, Jun Saito, Katsuhiko Murakami, Masanobu Hasegawa, Chidane Ouchi, Seima Kato, Takayuki Hasegawa, Akiyoshi Suzuki, Hideo Yokota, and Masahito Niibe
Appl. Opt. 46(27) 6783-6792 (2007)
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