Yi X, Vahala K, Li J, Diddams S, Ycas G, Plavchan P, Leifer S, Sandhu J, Vasisht G, Chen P, Gao P, Gagne J, Furlan E, Bottom M, Martin E C, Fitzgerald M P, Doppmann G, Beichman C
Department of Applied Physics and Materials Science, Pasadena, California 91125, USA.
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
Nat Commun. 2016 Jan 27;7:10436. doi: 10.1038/ncomms10436.
An important technique for discovering and characterizing planets beyond our solar system relies upon measurement of weak Doppler shifts in the spectra of host stars induced by the influence of orbiting planets. A recent advance has been the introduction of optical frequency combs as frequency references. Frequency combs produce a series of equally spaced reference frequencies and they offer extreme accuracy and spectral grasp that can potentially revolutionize exoplanet detection. Here we demonstrate a laser frequency comb using an alternate comb generation method based on electro-optical modulation, with the comb centre wavelength stabilized to a molecular or atomic reference. In contrast to mode-locked combs, the line spacing is readily resolvable using typical astronomical grating spectrographs. Built using commercial off-the-shelf components, the instrument is relatively simple and reliable. Proof of concept experiments operated at near-infrared wavelengths were carried out at the NASA Infrared Telescope Facility and the Keck-II telescope.
发现和表征太阳系外行星的一项重要技术依赖于对由轨道行星的影响所引起的宿主恒星光谱中微弱多普勒频移的测量。最近的一项进展是引入了光学频率梳作为频率参考。频率梳产生一系列等间距的参考频率，并且它们具有极高的精度和光谱分辨率，这有可能彻底改变系外行星的探测。在这里，我们展示了一种基于电光调制的替代梳状发生器方法的激光频率梳，其梳状中心波长稳定到分子或原子参考。与锁模频率梳不同，使用典型的天文光栅光谱仪可以很容易地分辨出线间距。该仪器采用商业现成组件构建，相对简单且可靠。在NASA红外望远镜设施和凯克二号望远镜上进行了在近红外波长下的概念验证实验。
