Using a broadband long-wavelength channel to increase the capture range of segment piston phase retrieval for segmented-aperture systems.

ABSTRACT

Segmented-aperture systems, such as the James Webb Space Telescope (JWST), require fine piston alignment between primary mirror segments. Computer simulation experiments show that using a broadband long-wavelength channel, illustrated with the Mid Infrared Instrument (MIRI) onboard the JWST, can extend the capture range of segment piston phase retrieval significantly (in the case of JWST with MIRI, up to hundreds of microns), greatly reducing the requirements on coarse phasing.