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arXiv 1802.01642astro-ph.IMphysics.ins-det
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光纤振摇对光纤径向速度谱仪模态噪声的抑制

Modal Noise Mitigation through Fiber Agitation for Fiber-fed Radial Velocity Spectrographs

Ryan R. Petersburg, Tyler M. McCracken, Dominic Eggerman, Colby A. Jurgenson, David Sawyer, Andrew E. Szymkowiak, Debra A. Fischer

摘要:

光纤模式噪声是近红外和可见光高精度光谱信噪比的限制因素。特别是在使用高度相干光源进行波长校准时,模态噪声会引起径向速度(RV)误差,从而阻碍低质量(可能类似地球)行星的发现。该领域的先前研究已经发现,通过使用积分球可以充分减轻模态噪声,但这需要非常明亮的光源,下一代高分辨率光谱仪不一定能提供这种奢侈品。否则,机械搅拌,“混合”纤维的模态模式,并允许噪声在几分钟长的曝光中平均,提供了一些降噪,但信噪比和RV漂移改善背后的确切机制尚未被社区充分探索或优化。因此,我们已经填写了模态噪声搅拌技术的参数空间,以更好地理解搅拌的贡献,减轻模态噪声,并发现一个更好的方法搅拌纤维。我们发现,模式噪声是最好的抑制的准混沌运动的两个高振幅的搅拌器振荡与不同的相位与大芯直径和低方位角对称性的光纤。这项工作随后影响了一个纤维搅拌器的设计,安装与EXTREME PRECISE光谱仪,我们估计将减少模态噪声引起的RV误差小于3.2厘米/秒。

英文摘要:

Optical fiber modal noise is a limiting factor for high precision spectroscopy signal-to-noise in the near-infrared and visible. Unabated, especially when using highly coherent light sources for wavelength calibration, modal noise can induce radial velocity (RV) errors that hinder the discovery of low-mass (and potentially Earth-like) planets. Previous research in this field has found sufficient modal noise mitigation through the use of an integrating sphere, but this requires extremely bright light sources, a luxury not necessarily afforded by the next generation of high-resolution optical spectrographs. Otherwise, mechanical agitation, which "mixes" the fiber's modal patterns and allows the noise to be averaged over minutes-long exposures, provides some noise reduction but the exact mechanism behind improvement in signal-to-noise and RV drift has not been fully explored or optimized by the community. Therefore, we have filled out the parameter space of modal noise agitation techniques in order to better understand agitation's contribution to mitigating modal noise and to discover a better method for agitating fibers. We find that modal noise is best suppressed by the quasi-chaotic motion of two high-amplitude agitators oscillating with varying phase for fibers with large core diameters and low azimuthal symmetry. This work has subsequently influenced the design of a fiber agitator, to be installed with the EXtreme PREcision Spectrograph, that we estimate will reduce modal-noise-induced RV error to less than 3.2 cm/s.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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