Determination of groove spacings for concave diffraction gratings
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China)
A long trace profiler (LTP) based method has been reported to measure the groove density of a concave grating with a curvature radius 14346.8 mm. It is appropriate for gratings with a sufficiently large curvature radius. Measurements of the groove density of a concave or convex grating with a small curvature radius could be problematic. A system based on a diffraction method and developed to check the groove variation of variable line spacing (VLS) gratings was used to measure a concave grating at NSRL recently and is the subject of this paper. For a grating with a small radius of curvature, the off-axis errors become dominant factors determining the system uncertainty. The errors are evaluated, and a correction algorithm is developed. A commercially available concave grating with a curvature radius of 750 mm was measured. The maximum relative groove density error ({delta}N/N) was 3x10{sup -5}.
- OSTI ID:
- 20643989
- Journal Information:
- Review of Scientific Instruments, Vol. 75, Issue 11; Other Information: DOI: 10.1063/1.1809287; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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Measurements of groove density for concave gratings with the long trace profiler
Measurements of groove density for concave gratings with the long trace profiler