Design of Vector-Vortex Coronagraphs for Exoplanet Science using a Six Meter Space Telescope

In this paper, we present a concept for an active, 6-meter space telescope (6MST) for space-based general astrophysics and consider its potential for coronagraphy. The telescope operates in spectral regions from about 100nm up to $\boldsymbol{2}\upmu\mathrm{m}$ , thus having the range comparable to Large Ultraviolet Optical Infrared Surveyor (LUVOIR) and Habitable Exoplanet Observatory (HabEx) in the longer wavelength end. In this paper, we produce the design for a vector-vortex coronagraph instrument for exoplanet work. We evaluate the impact of Primary Mirror (PM) segment gaps on the 20% broadband contrast floor when a charge 4 or charge 6 vortex mask and two $\boldsymbol{64}\mathrm{x}\boldsymbol{64}$ actuators sequential Deformable Mirrors (DM's) are used in the coronagraph, and compare the performance of a Lyot-mask and a pupil apodization mask relative to one another.