Papers by Keyword: Aspheric Mirror

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Authors: Takuya Kojima, Koji Usuki, Takao Kitayama, Daisuke Tonaru, Hiroki Matsumura, Junichi Uchikoshi, Yasuo Higashi, Katsuyosi Endo
Abstract: The development of a high-speed nanoprofiler is essential for developing the next generation of ultraprecision aspheric mirrors. The purpose of this study is to develop a new high-speed nanoprofiler that traces the normal vector of an aspheric mirror surface. The method of measurement adopted here is based upon the accuracy of a rotation goniometer. In order to attain a form measurement accuracy of PV1nm, it is necessary to improve the angle measurement accuracy. In this study, we equip a nanoprofiler with a rotary encoder that is calibrated in order to accomplish this objective, using a national standard machine. Consequently, this rotary encoder can be calibrated with an accuracy of ±0.12 μrad when considering the influence of installing the encoder on the nanoprofiler.
Authors: Xiao Jun Hu, Zi Wen Zheng, Yi Fan Dai, Sheng Yi Li
Abstract: A novel algorithm and experiment using phase retrieval to test aspheric mirror without auxiliary optical elements has been developed. To test aspheric mirror without auxiliary optical elements, a new algorithm has been invented to overcome the calculation difficulty due to the significant departure of aspheric surface from a sphere. In this algorithm, the aspheric surface is fitted into several annular ellipse sub-apertures, and each sub-aperture aberration can be retrieved the same as ball mirror testing. The whole aspheric surface can be retrieved by stitching all the subapertures together. An experiment has been carried out to test the validity of this algorithm.
Authors: Takao Kitayama, Daisuke Tonaru, Hiroki Matsumura, Junichi Uchikoshi, Yasuo Higashi, Katsuyosi Endo
Abstract: A new high-speed nanoprofiler was developed in this study. This profiler measures normal vectors and their coordinates on the surface of a specimen. Each normal vector is determined by making the incident light path and the reflected light path coincident using five-axis simultaneously controlled stages. From the acquired normal vectors and their coordinates, the three-dimensional shape is calculated by a reconstruction algorithm. In this study, a concave spherical mirror with a 400 mm radius of curvature was measured. As a result, a peak of 30 nm PV was observed at the centre of the mirror. Measurement repeatability was 1 nm. In addition, cross-comparison with a Fizeau interferometer was implemented and the results were consistent within 10 nm. In particular, the high spatial frequency profile was highly consistent, and any differences were considered to be caused by systematic errors.
Authors: Kwon Su Chon, Yoshiharu Namba, Kwon Ha Yoon
Abstract: Grazing incidence optics used in soft X-ray microscopes require supersmooth surface and highly accurate figure. We considered the fabrication of a Wolter type I mirror, one of grazing incidence optics, with axial-symmetric inner reflecting surfaces using single-point diamond turning. Electroless nickel was chosen as reflecting material Cutting conditions for machining the inner reflecting surface were restricted because of long arm of a single-crystal diamond tool. The machined Wolter type I mirror had approximately 270 nm P-V in figure error and 3 nm Ra in surface roughness. The direct-machined Wolter type I mirror could be successfully used in a soft Xray microscope based on laser-produced X-ray source.
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