Open AccessLaboratory demonstration of a broadband six-level phase mask coronagraph
Author(s) -
Fabien Patru,
Pierre Baudoz,
R. Galicher,
Qing Cao,
Kai Wang,
Lujing Xing,
Faouzi Boussaha,
Josiane Firminy,
Marion Bonafous
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.010007
Subject(s) - optics , apodization , coronagraph , broadband , photolithography , bandwidth (computing) , fabrication , materials science , exoplanet , physics , computer science , telecommunications , planet , medicine , alternative medicine , pathology , astrophysics
The six-level phase mask (SLPM) can be used in a focal plane as an efficient coronagraph [Opt. Express 22, 1884 (2014)]. It has several advantages: high-contrast imaging in broadband with small inner working angle; easy fabrication at low cost by photolithography and reactive ion etching processes; easy implementation with no need of pupil apodization. We present in this paper the first laboratory results demonstrating the high performance of a SLPM with an unobscured pupil. The on-axis attenuation reaches 2 × 10 -5 at λ = 800 nm and is better than 10 -4 over a 10% spectral bandwidth and better than 10 -3 over a 20% bandwidth. Finally, the detection of a planet can be achieved down to 1 λ/D.