MUSE Image Slicer: Test results on largest slicer ever manufactured

摘要

An image slicer breadboard has been designed, manufactured and tested for MUSE (Multi Unit Spectroscopic Explorer) instrument, a second generation integral field spectrograph developed for the European Southern Observatory (ESO) for the VLT. MUSE is operating in the visible and near IR wavelength range (0.465-0.93 μm) and is composed of 24 identical Integral Field Units; each one incorporates an advanced image slicer associated with a classical spectrograph.This paper describes the original optical design, the manufacturing, component test results (shape, roughness, reflectivity, microscopic visualization) and overall system performance (image quality, alignment) of the image slicer breadboard. This one is a combination of two mirror arrays of 48 elements each. It is made of Zerodur and uses a new polishing approach where all individual optical components are polished together by classical method. This image slicer constitutes the first one which has the largest number of active slices (48) associated with strict tolerances in term of positioning. The main results of the tests on this image slicer breadboard will then be presented. Most of them are compliant with requirements. This demonstrates that the manufacturing process is mature and gives good confidence for serial production applied to MUSE instrument.