Collaborative Research: Developing optimally customized-mode-selective photonic lanterns to enable the characterization of hundreds of exoplanets on solar system.

目前有超过5000颗已确认的行星围绕着太阳以外的恒星运行。能够分离和分析来自这些行星的光的颜色将提供丰富的信息，包括例如允许测量各种分子的组成和丰度，研究循环（天气）模式，并指出卫星的存在。能够进行这种特征描述的关键是能够将极其微弱的行星光与行星周围恒星的明亮眩光隔离开来。不幸的是，在已确认的5000多颗系外行星中，只有大约百分之一的行星具有这样的特征，而且这些行星都没有在我们太阳系大小的轨道内围绕它们的主恒星运行。该项目旨在推进一项被称为“光子灯笼”的关键技术，目的是消除污染的星光，以便在望远镜的角度分辨率限制内隔离和表征系外行星（绕另一颗恒星运行的行星）。研究人员将研究光子灯的独特设计，以最大限度地发挥消光（星光抑制）的效果，并与其他技术相结合，保持稳定性。该项目通过为学生提供在8米级望远镜的尖端设备上工作的独特机会，支持下一代仪器设计师的培训。最近在Keck望远镜上的KPIC仪器中投入使用的旋涡光纤Nuller （VFN）就是一个采用新技术的仪器的例子。它利用瞳孔平面涡流掩模和焦平面单模光纤（SMF），在1 λ/D的距离下，以19%的透射率拒绝星光和接受行星光。如果将SMF替换为6端口混合模式选择光子灯（PL），则行星总吞吐量将增加约2倍，并且其位置和亮度受到限制。用目前的SMF VFN方法，这两者都是不可能的。此外，PL实现了焦平面波前传感（WFS），消除了非共径和色差，从而加深和稳定了零。利用PL进行零化扩展了VFN的范围，可以直接表征数百颗巨型系外行星，为行星形成研究提供了可靠的样本。我们提出了一种新型的混合和模式选择PLs，用于优化机载WFS和8-10米望远镜的消零。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There are currently more than 5,000 confirmed planets orbiting stars other than our Sun. Being able to separate and analyze the colors of light from these planets would provide a wealth of information, including for example allowing for the measurement of composition and abundance of various molecules, to study circulation (weather) patterns, and to indicate the presence of moons. The key to being able to carry out such characterizations is the ability to isolate the extremely faint planetary light from the bright glare of the star the planet orbits around. Unfortunately, of the 5,000+ confirmed exoplanets, only about 1 in 100 have been characterized like this, and none of those are orbiting their host stars within orbits the size of our solar system. This project aims at advancing a key technology known as a “photonic lantern” for the purpose of eliminating contaminating starlight so that an exoplanet (a planet orbiting another star) can be isolated and characterized within the angular resolution limit of the telescope. The investigators will look into unique designs of photonic lanterns to maximize the effect of nulling (starlight suppression) and stability in tandem with other technologies. This project supports training of the next generation of instrument designers by providing unique opportunities for students to work at cutting edge facilities on 8-m class telescopes. The Vortex Fiber Nuller (VFN), recently commissioned within the KPIC instrument on the Keck Telescope, is an example of an instrument incorporating new technology. It utilizes a pupil-plane vortex mask followed by a focal-plane single-mode fiber (SMF) to reject starlight and accept planet light with ~19% transmission at 1 λ/D separation. If the SMF were replaced with a 6-port hybrid mode-selective photonic lantern (PL), the total planet throughput would be increased by ~2x, and its location and brightness constrained. Both are impossible with the current SMF VFN approach. In addition, the PL enables focal-plane wavefront sensing (WFS), eliminates non-common path and chromatic errors, thus deepening and stabilizing the null. Utilizing a PL for nulling extends the reach of VFN to allow hundreds of giant exoplanets to be directly characterized, providing a robust sample in the study of planet formation. We propose to develop novel hybrid and mode-selective PLs for optimal on-board WFS and nulling with 8-10 m telescopes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.