The fabrication of toroidal and coma-corrected toroidal diffraction gratings from spherical master gratings using elastically-deformable substrates - A progress reportA technique has been developed which permits toroidal, and coma-corrected toroidal, diffraction gratings to be replicated from spherical master gratings by the use of elastically-deformable substrates. Toroidal gratings correct for astigmatism and, thus, make it possible to construct stigmatic spectrometers that employ a single reflective diffraction grating. These spectrometers are particularly useful for the extreme-ultraviolet (EUV) wavelength range, where reflection coefficients are low, since the single optical surface provides for dispersion, focusing, and astigmatism correction. The fabrication procedures for the pure toroidal, and coma-corrected toroidal, gratings are described, and initial test results are presented. The use of the toroidal gratings in a high-resolution sounding-rocket EUV spectroheliometer, and in both the coronal diagnostics spectrometer and the ultraviolet coronagraph spectrometer on the ESA/NASA solar and heliospheric observatory mission, is described briefly, and the use of this technique for the fabrication of a coma-corrected toroidal grating for the prime Rowland spectrograph of the FUSE/Lyman mission is briefly discussed.
Document ID
19920062568
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Huber, Martin C. E. (ESTEC Noordwijk, Netherlands)
Timothy, J. G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Morgan, Jeffrey S. (Stanford University CA, United States)
Lemaitre, Gerard (Marseille Observatoire, France)
Tondello, Giuseppe (NASA Goddard Space Flight Center Greenbelt, MD, United States)