Extremely Large Telescope

Abstract:

We present the SWIFT image slicer and its novel de-magnifying design. It is based on the MPE-3D and SPIFFI image slicers, uses plane mirrors to slice the input field, but achieves a considerable de-magnification through the use of a mosaic of spherical lenses. As only plane and spherical surfaces are used in the design, classical polishing techniques can be applied to achieve very high surface accuracy and quality. This reduces aberrations and scattered light, mandatory for an image slicer working at optical wavelengths and behind an adaptive optics system. Except for the lens mosaic, the SWIFT slicer is built entirely from Zerodur and is assembled using optical contacting. We present a detailed description of the design as well as results of the early stages of its fabrication.