An Image Slicer Integral Field Unit with Diffraction‐limited Performance for Three‐Dimensional Imaging Spectroscopy

Abstract

ABSTRACTWe have designed and constructed an advanced image slicer (AIS) integral field unit (IFU). The IFU employs an all‐mirror design and will be installed in the Penn State near‐IR Imager and Spectrograph (PIRIS) for three‐dimensional integral field spectroscopy at various astronomical telescopes. Using the AIS technique, the slicer IFU can preserve the telescope’s focal ratio and pupil (both position and size) while maximizing the packing efficiency for three‐dimensional data on the detector. Compared to other existing AIS IFU designs, our design, which uses monolithic optical components for both pupil and field mirror arrays, provides a convenient engineering solution for manufacturing, using the state‐of‐the‐art diamond‐turning machines and alignment of the IFU optics. Our slicer mirror array was also manufactured by diamond turning, with all the mirrors simultaneously machined, which also simplifies the procedure for the manufacture and the assembly of the mirrors. We present the IFU optical description, component test results, and overall IFU system performance. We also discuss possible science applications using the IFU.