ESA Science & Technology - NIRSpec IFU image slicer

The Integral Field Unit (IFU) of the NIRSpec instrument allows for spectral imaging of extended astronomical objects. A key element of the IFU is the image slicer, which cuts the 3 arcsec × 3 arcsec field of view into 30 slices of 0.1 arcsec × 3 arcsec. Each slice gives rise to 30 contiguous spectra on the detectors for a total of 900 spectra, each corresponding to a tiny spatial element of size 0.1 arcsec × 0.1 arcsec.

The image slicer is pictured here after diamond machining. Each of the 30 slices is less than 1 mm wide and has its own curve and tilt.