In high-contrast imaging optical systems for direct observation of planets outside our solar system, adaptive optics with an accuracy of lambda/10,000 root mean square is required to reduce the speckle noise down to 1e-10 level in addition to the nulling coronagraph which eliminate the diffracted light. We developed the speckle area nulling (SAN) method as a new dark-hole control algorithm which is capable of controlling speckle electric field in a wide area quickly, in spite of an extension of speckle nulling, and is robust not relying upon an optical model. We conducted a validation experiment for the SAN method with a monochromatic light and succeeded in reducing the intensity of areal speckles by 4.4e-2.
@article{arxiv.2204.09834,
title = {Coronagraph Experiment on Dark-hole Control by Speckle Area Nulling Method},
author = {Masahito Oya and Jun Nishikawa and Masaaki Horie and Kazuma Sato and Naoshi Murakami and Takayuki Kotani and Shiomi Kumagai and Motohide Tamura and Yosuke Tanaka and Takashi Kurokawa},
journal= {arXiv preprint arXiv:2204.09834},
year = {2022}
}