AI 中文总结
研究围绕LIFE项目展开，旨在实现对类地系外行星的成像和特征描述。通过探索用特定光纤及模拟PIAA性能，实现宽带空间滤波，可达成>95%的宽带几何耦合效率，为LIFE项目在大带宽上实现深零值深度提供支持。
AI 中文摘要
零值干涉测量法是地基和天基天文台对系外行星进行中红外成像和特征描述最有前景的技术之一。地面上，即将用于甚大望远镜干涉仪（VLTI）的阿斯加德/北欧光学望远镜（Asgard/NOTT）访客仪器有望成为首个观测年轻巨型系外行星的零值干涉仪。大型系外行星干涉仪（LIFE）项目旨在在太空实施长基线零值干涉测量法，以对类地系外行星进行成像和特征描述。LIFE要求在中红外（MIR：4 - 18.5μm）的大带宽上达到深度（<10⁻⁵）零值深度且具有高吞吐量（>15%）。为实现深零值深度，需空间滤波器消除波前像差。然而，在如此大带宽上实现高通量（>95%）的高效空间滤波具有挑战性。本研究探索了使用先前为达尔文任务提议研究的两种阶跃折射率光纤：碲 - 砷 - 硒硫系（TAS）和卤化银（AgBr）光纤进行宽带空间滤波的可能性。利用$\partial$Lux，还模拟了用非球面镜进行相位诱导幅度切趾（PIAA）的性能，以对光束的光瞳平面进行消色差切趾并提高其在两种光纤中的耦合效率。结果表明，PIAA镜的制造精度<100nm时，可实现>95%的宽带几何耦合效率。因此，LIFE光束的消色差切趾与由所用空间滤波器数量定义的≥2个光谱通道兼容。
英文摘要
Nulling interferometry is one of the most promising techniques that is envisioned for the imaging and characterization of exoplanets in the mid-infrared for ground-based and space-based observatories. On the ground, the upcoming Asgard/NOTT visitor instrument for the Very Large Telescope Interferometer (VLTI) is expected to be the first nuller to observe young giant exoplanets. The Large Interferometer For Exoplanets (LIFE) project aims at implementing long-baseline nulling interferometry in space to image and characterize Earth-like exoplanets. LIFE requires to reach deep ($<10^{-5}$) null depths over a large bandwidth in the mid-infrared (MIR: 4-18.5$\,μ$m) with a high throughput ($>15\,\%$). These requirements are necessary to detect and characterize the thermal emission of Earth-like exoplanets. To achieve deep null depths, a spatial filter is necessary to wash away the wavefront aberrations that would otherwise be a limiting factor for the contrast. However, efficient spatial filtering with high throughput ($>95\,\%$) is challenging to achieve over such a large bandwidth. In this study, we explore the possibility of broadband spatial filtering using two step-index fibers previously studied for the Darwin mission proposal: Te-As-Se chalcogenide (TAS) and silver halide (AgBr) fibers. Using $\partial$Lux, we also simulate the performance of phase-induced amplitude apodization (PIAA) with aspherical mirrors to achromatically apodize the pupil plane of a beam and improve its coupling efficiency in both fibers. The results show that a broadband geometric coupling efficiency of $>95\,\%$ can be achieved, with a manufacturing precision of $<100\,$nm for the PIAA mirrors. An achromatic apodization of the beams for LIFE is therefore compatible with a number of spectral channels of $\geq2$, defined by the number of spatial filters used.
Comments10 pages (incl. 8 figures); Proc. SPIE Astronomical Telescopes + Instrumentation 2026 (Copenhagen; Denmark), Optical and Infrared Interferometry and Imaging X
