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Design and verification of an aberration-corrected free-form concave blaze grating with variable line spacing for hyperspectral imaging (Conference Presentation)
Author(s): Cheng-Hao Ko; Bang-Ji Wang; Jih-Run Tsai; Yueh-Hsun Wu; Sheng-Yu Tsai; Shin-Fa Lin; Chiu-Der Hsiao

Paper Abstract

A flat-field aberration corrected concave blaze grating for 400-1100nm is designed and fabricated. The concave grating, which has a free-form profile with blaze grating pitch and variable line spacing, is fabricated using five-axis CNC machine with nanometer machining precision. An optical system is setup to measure the focused spot size, spectral resolution and diffraction efficiency to evaluate the performance of aberration-corrected concave grating. The blaze grating reaches a diffraction efficiency of 70%. The focused vertical spot size is 50µm, which indicates a 50µm spatial resolution at the image plane. The focused horizontal spot size is 300µm, which converts to a spectral resolution of 6nm. The design methodology can be applied to an Offner type hyperspectral imager with a free-form convex grating and variable line spacing to achieve high efficiency and high spatial and high spectral resolving power.

Paper Details

Date Published: 9 June 2017
PDF: 1 pages
Proc. SPIE 10213, Hyperspectral Imaging Sensors: Innovative Applications and Sensor Standards 2017, 1021307 (9 June 2017); doi: 10.1117/12.2261647
Show Author Affiliations
Cheng-Hao Ko, National Taiwan Univ. of Science and Technology (Taiwan)
Bang-Ji Wang, National Space Organization (Taiwan)
Jih-Run Tsai, National Space Organization (Taiwan)
Yueh-Hsun Wu, National Taiwan Univ. of Science and Technology (Taiwan)
Sheng-Yu Tsai, National Taiwan Univ. of Science and Technology (Taiwan)
Shin-Fa Lin, National Space Organization (Taiwan)
Chiu-Der Hsiao, National Space Organization (Taiwan)


Published in SPIE Proceedings Vol. 10213:
Hyperspectral Imaging Sensors: Innovative Applications and Sensor Standards 2017
David P. Bannon, Editor(s)

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