Development of compact metal-mirror image slicer unit for optical telescope of the SOLAR-C mission

To realize an integral field unit (IFU) for a one-meter class optical telescope (SUVIT) on board Japanese next solar mission (SOLAR-C), we studied an optical design and manufacturing method to attain high optical performances for IFU, using a novel manufacturing technique developed by Canon. The IFU consists of micro-image slicer of 45 arrayed 30-micron-thick metal mirrors and a pseudo-pupil mirror array for making three pseudo-slits, providing possible optical configuration for a coexistence with a usual slit spectrograph without movable mechanism. The IFU mirrors were deposited by a protected silver coating for high reflectivity in visible and near IR wavelength region. We present the optical design, performance of prototype IFU and space qualification tests of the silver coating.