Fraunhofer IOF built an 85-micrometre double slit for ESA's FLEX fluorescence spectrometer
Fraunhofer IOF in Jena has described the silicon double-slit assembly and two high-precision mirrors it built for FLORIS, the imaging spectrometer on ESA's FLEX mission, set to launch on 15 September 2026. Each slit is 85 micrometres wide over 44.15 millimetres. FLORIS is designed to measure the faint fluorescence sunlight excites in plants, a signal that tracks photosynthetic activity, health and stress. The FLEX mission has not yet launched; those measurements remain a plan.
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Fraunhofer IOF describes a silicon double slit and two mirrors for FLORIS
Fraunhofer IOF in Jena has described the silicon double-slit assembly and two high-precision mirrors it built for FLORIS, the imaging spectrometer aboard ESA's FLEX mission. Phys.org says the mission is set to launch on 15 September 2026. Fraunhofer IOF schedules the launch for mid-September. FLORIS is designed to measure the faint fluorescence that sunlight excites in plants, a signal that tracks photosynthetic activity, health and stress in vegetation.[1], [2]
Each FLORIS slit is 85 micrometres wide over 44.15 millimetres
Each of FLORIS's two slits is 85 micrometres wide along 44.15 millimetres, with a permitted deviation of one micrometre and positioning in its mount held under five micrometres. Fraunhofer IOF says the silicon element sits in its holder to within five micrometres and slit flatness is under ten micrometres. Mirror surfaces were polished to a roughness of 0.3 nanometres rms. Fraunhofer IOF developed a lithographic process chain for structuring silicon wafers, then coated the slits black to suppress reflections.[1], [2]
Falk Kemper puts weak fluorescence against a mission not yet launched
Falk Kemper said the fluorescence signals plants emit are very weak, and that the optical components have to be made and assembled with exceptional precision. Falk Kemper said the fabrication pushed the limits of what is technically feasible. OHB System is prime contractor, with Leonardo and Thales Alenia Space. The FLEX mission has not yet launched; its measurements remain a plan.[1], [2]
