InnoPOL: an EMCCD imaging polarimeter and 85-element curvature AO system on the 3.6-m AEOS telescope for cost effective polarimetric speckle suppression

TL;DR

InnoPOL is a new EMCCD-based polarimeter integrated with an 85-element curvature adaptive optics system on the AEOS telescope, designed for cost-effective polarimetric speckle suppression and performance testing in high-contrast imaging.

Contribution

The paper introduces InnoPOL, a novel EMCCD imaging polarimeter combined with an AO system, utilizing off-the-shelf components for cost-effective polarimetric speckle suppression and performance optimization.

Findings

Models show slow polarization modulation affects speckle suppression.

Initial EMCCD data verifies model predictions.

Trade-offs between instrument performance and noise sources are analyzed.

Abstract

The Hokupa'a-85 curvature adaptive optics system components have been adapted to create a new AO-corrected coud\'{e} instrument at the 3.67m Advanced Electro-Optical System (AEOS) telescope. This new AO-corrected optical path is designed to deliver an f/40 diffraction-limited focus at wavelengths longer than 800nm. A new EMCCD-based dual-beam imaging polarimeter called InnoPOL has been designed and is presently being installed behind this corrected f/40 beam. The InnoPOL system is a flexible platform for optimizing polarimetric performance using commercial solutions and for testing modulation strategies. The system is designed as a technology test and demonstration platform as the coud\'{e} path is built using off-the-shelf components wherever possible. Models of the polarimetric performance after AO correction show that polarization modulation at rates as slow as 200Hz can cause speckle correlations in brightness and focal plane location sufficient enough to change the speckle suppression behavior of the modulators. These models are also verified by initial EMCCD scoring camera data at AEOS. Substantial instrument trades and development efforts are explored between instrument performance parameters and various polarimetric noise sources.