The high-contrast spectroscopy testbed for segmented telescopes (HCST): new wavefront control demonstrations

The High-Contrast Spectroscopy Testbed for Segmented Telescopes (HCST) in the Exoplanet Technology Laboratory (ET Lab) at Caltech is designed to test the technologies that will enable direct imaging and characterization of exoplanets with future segmented ground- and space-based telescopes. Wavefront sensing and control has been successfully implemented with electric field conjugation (EFC) using the FALCO Matlab package, yielding a baseline raw contrast of 1×10^(-8) in narrowband light with a Vector Vortex Coronagraph over a clear aperture. Here we report on progress towards our next HCST milestones: 1- Demonstration of 10^(-8) raw contrast levels in broadband light with the apodized vortex coronagraph using a LUVOIR B-like segmented aperture. 2- Integration of a fiber injection unit (FIU) and corresponding wavefront control algorithm to achieve 10^(-8) raw contrast in broadband light through a single mode fiber enabling high dispersion coronagraphy.