The JWST Near Infrared Imager and Slitless Spectrograph (NIRISS) instrumentation includes internal optical components, filters, grisms, and an aperture mask to support its 4 observing modes. 

The NIRISS instrument consists of hardware components that define 4 observing modes.  These components are:

• Transfer optics:
  • a pick-off mirror (POM), which also includes the focus mechanism, 
  • a 3-mirror assembly (TMA) to collimate the incoming beam, and 
  • a camera TMA to focus light on the detector.
• Pupil and filter wheels as a dual-wheel assembly:
  
  • filters—12 bandpass filters (7 wideband and 5 medium-band) distributed equally between the pupil and filter wheel;
  • GR150C and GR150R—a pair of grisms in the filter wheel that operate between 0.8 and 2.2 μm with R ≈ 150. These grisms are identical but oriented to disperse in orthogonal directions on the detector;
  • GR700XD—a grism in the pupil wheel that operates between 0.6 and 2.8 μm with R ≈ 700, which is optimized for applications that require high spectro-photometric precision; and
  • a non-redundant aperture mask (NRM) in the pupil wheel that enables high spatial resolution imaging with medium contrast.
    
• Detector: a single Hawaii 2RG sensor chip array with 2048 × 2048 pixels. Each pixel is 18 × 18 μm and provides a plate scale of 0.0653"/pixel × 0.0658"/pixel.

The full list of NIRISS instrumentation articles: