We demonstrate a key step along a technical route to achieving cm/s scale accuracy for astronomical spectrographs over long (multi-year) time scales, which is critical for the Doppler characterization of Earth sized exoplanets, and measurement of small cosmic redshift drift over many years. This same technique also enables searching exoplanet atmospheres for biosignificant molecules in direct planet imaging using, otherwise, insufficiently low resolution and drift prone dispersive (grating or prism) spectrographs. Using a method called crossfading for externally dispersed interferometers (EDIs) to get highly robust spectra, we recently demonstrated a factor of 1000 × reduction in the net shift of an EDI measured ThAr line to a deliberate simulated wavelength translation of the detector. This 1000 × gain in disperser stability can be combined with conventional stability gains afforded by fiber scramblers, vacuum tanks, and thermal control, to provide an additional 1 to 3 orders of magnitude reduction in the net point spread function shift drift. Crossfading combines high- and low-delay fringing signals that react oppositely in phase to cancel their net reaction to a detector wavelength drift. This can be implemented by an interferometer addition to a facility spectrograph.

中文翻译：

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使用具有交叉淡化延迟对的干涉测量法将色散光谱仪稳定性提高 1000 倍的方法

我们展示了在长（多年）时间尺度上实现天文光谱仪 cm/s 尺度精度的技术路线上的关键一步，这对于地球大小的系外行星的多普勒表征以及测量许多小宇宙红移漂移至关重要年。同样的技术还可以在直接行星成像中搜索系外行星大气中的生物重要分子，否则，分辨率不够低且易于漂移的色散（光栅或棱镜）光谱仪。使用称为外部分散干涉仪 (EDI) 的交叉衰落的方法来获得高度稳健的光谱，我们最近证明了 EDI 测量的 ThAr 线的净位移减少了 1000 倍，从而使探测器的故意模拟波长转换减少了 1000 倍。这种 1000 倍的色散稳定性增益可以与光纤加扰器、真空罐和热控制提供的传统稳定性增益相结合，使净点扩散函数偏移漂移额外减少 1 到 3 个数量级。交叉淡化结合了高延迟和低延迟边缘信号，这些信号在相位上反应相反，以抵消它们对检测器波长漂移的净反应。这可以通过将干涉仪添加到设备光谱仪来实现。