Manufacturing and coating of optical components for the EnMAP hyperspectral imager

M. Schürmann, D. Gäbler, R. Schlegel, S. Schwinde, T. Peschel, C. Damm, R. Jende, J. Kinast, S. Müller, M. Beier, S. Risse, B. Sang (+5 others)
2016 Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II  
Modern space-born spectrometer applications more and more rely on highest-precision slit devices defining the spectrometer entrance aperture. Reason for this is the increasing demand for broadband and high-resolving spectrometer or imaging spectrometer applications. High-NA optics necessitate very thin (microns) and accurate slit structures, whose manufacturing is demanding or impossible with common technology. In addition, they must withstand harsh environmental loads like shock, vibration and
more » ... hock, vibration and thermal cycling. The hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) satellite mission comprises two spectrometers whose entrance slits are realized by an all-silicon, highly integrated double slit device. It is manufactured by use of micro-machining and lithographic processes, reaching sub-micron geometric precision. Each slit aperture is 24 µm x 24 mm large, corresponding to an aspect ratio of 1:1000. In some critical respectssuch as planarity or coalignmentthe technology excells established manufacturing technologies like metal electroforming, milling and others. In addition to slit aperture definition, the double slit device achieves field separation for the two imaging spectrometers. One of the two transmitted light beams is deflected by a flat mirror. The minute silicon mirror is completely integrated into the device. The EnMAP slit assembly has undergone an intensive qualification test program. Included were vibrational, shock and thermal load tests as well as a more specific sun intrusion test. The results of these tests are briefly presented and discussed.
doi:10.1117/12.2232914 fatcat:fhl73paiijdorn4anoheennqny