The space coronagraph optical bench (SCoOB): 4. vacuum performance of a high contrast imaging testbed

Kyle Van Gorkom; Ewan S Douglas; Kian Milani; Jaren N Ashcraft; Ramya M Anche; Emory Jenkins; Patrick Ingraham; Sebastiaan Haffert; Daewook Kim; Heejoo Choi; Olivier Durney

arXiv · 2406.18885

The space coronagraph optical bench (SCoOB): 4. vacuum performance of a high contrast imaging testbed

Kyle Van Gorkom·Ewan S Douglas·Kian Milani·Jaren N Ashcraft·Ramya M Anche·Emory Jenkins·Patrick Ingraham·Sebastiaan Haffert·Daewook Kim·Heejoo Choi·Olivier Durney

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Abstract

The Space Coronagraph Optical Bench (SCoOB) is a high-contrast imaging testbed built to demonstrate starlight suppression techniques at visible wavelengths in a space-like vacuum environment. The testbed is designed to achieve ${<}10^{-8}$ contrast from $3-10\lambda/D$ in a one-sided dark hole using a liquid crystal vector vortex waveplate and a 952-actuator Kilo-C deformable mirror (DM) from Boston Micromachines (BMC). We have recently expanded the testbed to include a field stop for mitigation of stray/scattered light, a precision-fabricated pinhole in the source simulator, a Minus K passive vibration isolation table for jitter reduction, and a low-noise vacuum-compatible CMOS sensor. We report the latest contrast performance achieved using implicit electric field conjugation (iEFC) at a vacuum of ${\sim}10^{-6}$ Torr and over a range of bandpasses with central wavelengths from 500 to 650nm and bandwidths (BW) from $\ll 1\%$ to 15\%. Our jitter in vacuum is $<3\times10^{-3} \lambda/D$, and the best contrast performance to-date in a half-sided D-shaped dark hole is $2.2\times10^{-9}$ in a $\ll 1 \%$ BW, $4\times10^{-9}$ in a 2\% BW, and $2.5\times10^{-8}$ in a 15\% BW.

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Kyle Van Gorkom, Ewan S Douglas, Kian Milani, Jaren N Ashcraft, Ramya M Anche, Emory Jenkins, Patrick Ingraham, Sebastiaan Haffert, Daewook Kim, Heejoo Choi, Olivier Durney. 2024-06-27. The space coronagraph optical bench (SCoOB): 4. vacuum performance of a high contrast imaging testbed. https://arxiv.org/abs/2406.18885

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