The Santa Cruz Extreme AO Lab (SEAL): Design and First Light

Abstract: The Santa Cruz Extreme AO Lab (SEAL) is a new visible-wavelength testbed designed to advance the state of the art in wavefront control for high contrast imaging on large, segmented, ground-based telescopes. SEAL provides multiple options for simulating atmospheric turbulence, including rotating phase plates and a custom Meadowlark spatial light modulator that delivers phase offsets of up to 6pi at 635nm. A 37-segment IrisAO deformable mirror (DM) simulates the W. M. Keck Observatory segmented primary mirror. The adaptive optics system consists of a woofer/tweeter deformable mirror system (a 97-actuator ALPAO DM and 1024-actuator Boston Micromachines MEMs DM, respectively), and four wavefront sensor arms: 1) a high-speed Shack-Hartmann WFS, 2) a reflective pyramid WFS, designed as a prototype for the ShaneAO system at Lick Observatory, 3) a vector-Zernike WFS, and 4) a Fast Atmospheric Self Coherent Camera Technique (FAST) demonstration arm, consisting of a custom focal plane mask and high-speed sCMOS detector. Finally, science arms preliminarily include a classical Lyot-style coronagraph as well as FAST (which doubles as a WFS and science camera). SEAL's real time control system is based on the Compute and Control for Adaptive optics (CACAO) package, and is designed to support the efficient transfer of software between SEAL and the Keck II AO system. In this paper, we present an overview of the design and first light performance of SEAL.