A coronagraph based on two spatial light modulators for active amplitude apodizing and phase corrections

Jiangpei Dou; Deqing Ren; Xi Zhang; Yongtian Zhu; Gang Zhao; Zhen Wu; Rui Chen; Chengchao Liu; Feng Yang; Chao Yang

doi:10.1117/12.2055327

6 August 2014 A coronagraph based on two spatial light modulators for active amplitude apodizing and phase corrections

Jiangpei Dou, Deqing Ren, Xi Zhang, Yongtian Zhu, Gang Zhao, Zhen Wu, Rui Chen, Chengchao Liu, Feng Yang, Chao Yang

Proceedings Volume 9147, Ground-based and Airborne Instrumentation for Astronomy V; 91478O (2014) https://doi.org/10.1117/12.2055327
Event: SPIE Astronomical Telescopes + Instrumentation, 2014, Montréal, Quebec, Canada

Abstract

Almost all high-contrast imaging coronagraphs proposed until now are based on passive coronagraph optical components. Recently, Ren and Zhu proposed for the first time a coronagraph that integrates a liquid crystal array (LCA) for the active pupil apodizing and a deformable mirror (DM) for the phase corrections. Here, for demonstration purpose, we present the initial test result of a coronagraphic system that is based on two liquid crystal spatial light modulators (SLM). In the system, one SLM is served as active pupil apodizing and amplitude correction to suppress the diffraction light; another SLM is used to correct the speckle noise that is caused by the wave-front distortions. In this way, both amplitude and phase error can be actively and efficiently compensated. In the test, we use the stochastic parallel gradient descent (SPGD) algorithm to control two SLMs, which is based on the point spread function (PSF) sensing and evaluation and optimized for a maximum contrast in the discovery area. Finally, it has demonstrated a contrast of 10^-6 at an inner working angular distance of ~6.2 λ/D, which is a promising technique to be used for the direct imaging of young exoplanets on ground-based telescopes.

Citation Download Citation

Jiangpei Dou, Deqing Ren, Xi Zhang, Yongtian Zhu, Gang Zhao, Zhen Wu, Rui Chen, Chengchao Liu, Feng Yang, and Chao Yang "A coronagraph based on two spatial light modulators for active amplitude apodizing and phase corrections", Proc. SPIE 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91478O (6 August 2014); https://doi.org/10.1117/12.2055327

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available