High-contrast imager for Complex Aperture Telescopes (HiCAT): 3. first lab results with wavefront control

TL;DR

HiCAT is a high-contrast imaging testbed for complex aperture telescopes, demonstrating initial wavefront control results and innovative coronagraph designs that enhance imaging performance and robustness.

Contribution

This paper presents the first lab results of HiCAT with wavefront control and introduces advanced APLC coronagraph designs tailored for complex telescope geometries.

Findings

Achieved a wavefront error of 12nm rms over an 18mm pupil.

Demonstrated initial wavefront control with a classical Lyot coronagraph.

Developed APLC solutions that are robust to jitter and low-order aberrations.

Abstract

HiCAT is a high-contrast imaging testbed designed to provide complete solutions in wavefront sensing, control and starlight suppression with complex aperture telescopes. The pupil geometry of such observatories includes primary mirror segmentation, central obstruction, and spider vanes, which make the direct imaging of habitable worlds very challenging. The testbed alignment was completed in the summer of 2014, exceeding specifications with a total wavefront error of 12nm rms over a 18mm pupil. The installation of two deformable mirrors for wavefront control is to be completed in the winter of 2015. In this communication, we report on the first testbed results using a classical Lyot coronagraph. We also present the coronagraph design for HiCAT geometry, based on our recent development of Apodized Pupil Lyot Coronagraph (APLC) with shaped-pupil type optimizations. These new APLC-type solutions using two-dimensional shaped-pupil apodizer render the system quasi-insensitive to jitter and low-order aberrations, while improving the performance in terms of inner working angle, bandpass and contrast over a classical APLC.