Speckle reduction technique using the self-coherent camera for the common-path visible nulling coronagraph
Speckle reduction technique using the self-coherent camera for the common-path visible nulling coronagraph
复制标题
共路径可见调零日冕仪自相干相机的散斑抑制技术
DOI：
10.1117/12.2560471
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Motohide Tamura
中科院分区：
文献类型：
--
作者：
Kenta Yoneta;Naoshi Murakami;Koki Yoshida;Ryuta Koike;Takayuki Kotani;Hajime Kawahara;Naoshi Baba;Motohide Tamura
由于主星星和行星之间的高对比度，直接探测微弱的系外行星是具有挑战性的。高对比度成像系统在直接探测系外行星方面具有重要作用。该系统由电晕放电和散斑抑制技术组成。共光路可见零日冕仪（VNC）由于其光学结构简单、消色差等优点，成为高对比度观测的重要手段之一。在共光路VNC中引入了空间光调制器（SLM）来抑制波前像差引起的残余散斑。由于其大像素格式，SLM可能会产生巨大的黑洞。作为焦平面波前传感器，我们利用自相干相机（SCC）的方法，共光路VNC。我们进行了实验室演示的散斑抑制技术的共路VNC结合SCC的方法。实验结果表明，在波长为633 nm的单色光中，初始对比度为2.2 × 10- 5，最终对比度为1.3 × 10- 6。我们讨论了对比度的限制因素，以改进我们的演示，以实现更高的对比度。
Direct detection of faint exoplanets is challenging due to a high-contrast ratio between a primary star and a planet. A high-contrast imaging system has an important role in directly detecting exoplanets. The system consists of coronagraph and speckle reduction technique. A common-path visible nulling coronagraph (VNC) is one of the attracting methods for high-contrast observation because of a simple optical configuration and achromatic stellar elimination. We introduced a spatial light modulator (SLM) into the common-path VNC to suppress residual speckles caused by wavefront aberrations. The SLM can potentially generate a huge dark hole thanks to its large pixel format. As a focal plane wavefront sensor, we utilized the self-coherent camera (SCC) method for the common-path VNC. We carried out the laboratory demonstration of the speckle reduction technique for the common-path VNC combined with the SCC methods. The experimental results show an initial contrast of 2.2 × 10-5and a final contrast of 1.3 × 10-6in monochromatic light at a wavelength of 633 nm. We discuss the limiting factors of the contrast for improvement of our demonstration to achieve the higher contrast.