AI 中文总结
本文针对传统系外行星探测技术的局限，研究光子集成电路的三耦合器零差能力，为系外行星直接探测提供紧凑可扩展的高对比度技术方案。
AI 中文摘要
太阳系类似的气态巨行星和宜居带类地行星，用凌星法、视向速度法和直接成像等传统系外行星探测与表征技术很难观测到。多孔径长基线零差干涉仪可抑制恒星光，能以比单孔径望远镜上传统日冕仪更高的空间分辨率探测到微弱的行星信号。借助电信行业的技术进步，光子集成电路（PIC）为天文应用所需的光学操作提供了有前景的平台，包括长基线和跨孔径配置下零差干涉仪的相位调整与光束组合。与体光学相比，PIC提供了紧凑、可扩展的架构，对对准以及热和机械扰动的敏感性更低。然而，其设计和制造精度仍不足以满足系外行星仪器的严格要求。本文中，我们研究光子三耦合器的零差能力，该器件由三个等宽波导组成，其对称结构在光束组合时具有产生消色差零差的几何倾向。在实验室中，我们表征了1.55μm单色光下的零差深度，器件基于平面硅上二氧化硅平台。在宽带H波段光中，我们探究了热光相位调制器等组件的色差效应，该调制器用于精细相位调整。我们正在开展的工作旨在使PIC成熟，以用于系外行星的直接探测和大气表征，这将为未来天基天文台（如宜居世界天文台）的高对比度技术提供可扩展的测试和部署支持。
英文摘要
Solar System analog gas giants and habitable-zone terrestrial planets are observationally elusive to conventional exoplanet detection and characterization techniques, i.e. transits, radial velocities, and direct imaging. Long baseline nulling interferometry across multiple apertures suppresses starlight and enables detection of faint planetary signals at higher spatial resolution than traditional coronagraphs on single-aperture telescopes. Leveraging technological advancements from the telecommunications industry, photonic integrated circuits (PICs) offer a promising platform for performing the optical operations necessary for astronomical applications, including phasing and beam combination for nulling interferometry in both long-baseline and cross-aperture configurations. PICs provide compact, scalable architectures with reduced sensitivity to alignment as well as thermal and mechanical perturbations compared to bulk optics. However, their design and manufacturing precision remain insufficient for the stringent requirements of exoplanet instrumentation. Here, we investigate the nulling capabilities of photonic tricouplers, devices composed of three equal-width waveguides that are geometrically predisposed to produce achromatic nulls upon beam combination through their symmetric construction. In the laboratory, we characterize null depths in monochromatic light at 1.55 $\mathrmμ$m with devices on a planar silica-on-silicon platform. In broadband $H$-band light, we explore chromatic effects from components such as thermo-optic phase modulators used for fine-phasing. Our ongoing efforts towards maturation of PICs for direct detection and atmospheric characterization of exoplanets will support scalable testing and deployment of high-contrast technologies for future space-based observatories, such as the Habitable Worlds Observatory.
Comments14 pages, 10 figures, SPIE Astronomical Telescopes and Instrumentation proceeding submitted to "Optical and Infrared Interferometry and Imaging X"
