High-contrast imager for complex aperture telescopes (HiCAT): 6. Two deformable mirror wavefront control (Conference Presentation)

Abstract

The goal of the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed is to demonstrate coronagraphic starlight suppression solutions for future segmented aperture space telescopes such as the Large UV, Optical, IR telescope (LUVOIR) mission concept being studied by NASA. The testbed design has the flexibility to enable studies with increasing complexity for telescope aperture geometries starting with off-axis telescopes, then on-axis telescopes with central obstruction and support structures. The testbed implements the Apodized Pupil Lyot Coronagraph (APLC) optimized for the HiCAT aperture, which is similar to one of the possible geometries considered for LUVOIR. Wavefront can be controlled using continuous deformable mirrors, and wavefront sensing is performed using the imaging camera, or a dedicated phase retrieval camera, and also in a low-order wavefront sensing arm. We present a progress update of the testbed in particular results using two deformable mirror control to produce high-contrast dark zone, and preliminary results using the testbed’s low order Zernike wavefront sensor.