The JWST Mid-Infrared Instrument (MIRI) provides 4 observing modes from 5 to 28.5 μm that include optical, spectral, and occulting capabilities.
The major pieces of instrumentation hardware necessary to support these modes include the components listed below:
- Optics and focal plane—the imager (MIRIM) and medium resolution spectrometer (MRS) are fed from a single pick-off mirror (POM).
- Filters—there are 10 filters for imaging, 4 filter-diaphragm combinations for coronagraphy, one neutral density filter, one ZnS-Ge double prism for the LRS mode, one opaque position for darks, and one for a lens used during ground tests.
- Coronagraph masks—one occulter is based on the classic Lyot design and there are 3 occulters that incorporate 4-quadrant phase masks (4QPMs).
- Spectroscopic elements—a double prism is used for the low-resolution spectrometer and there are 2 dichroic filter combination wheels for the medium-resolution spectrometer.
- Detectors are 3 impurity band conduction (Si:As IBC) devices.
- Integral field units (IFUs)—there are 4 IFUs for the medium resolution spectrometer.