Tunable Fabry-Perot Frequency Comb for Precision Doppler Measurements

在过去的二十年里，对数以千计的系外行星的探测使我们对太阳系的看法发生了哥白尼式的转变。我们现在知道，我们银河系中的大多数恒星都是由行星组成的。我们还知道，与1995年首次探测到的气态巨行星相比，低质量行星更为常见。然而，用目前的仪器无法测量真正的类似地球的行星质量(质量相似，在宜居带轨道上)。这项建议解决了提高精度的关键要求，开发了一种精确、准确和稳定的波长校准系统，用于使用新一代超稳定光谱仪测量径向速度。该项目将为学生和职业生涯早期的科学家提供培训机会，并有助于保持美国在一个吸引公众想象的科学领域的竞争力。可调法布里-佩罗(FP)梳子的设计稳定在1厘米/S的水平，窄线可用于校准一些仪器的不确定度。发射梳状光谱是通过FP干涉仪对一个明亮的宽带激光驱动光源进行滤波而产生的。梳状峰的位置由FP腔的间距决定。为了防止位置漂移，梳子将被锁定到超精细激光过渡，精度超过百亿分之一。为了防止梳子的自由光谱范围或色散发生变化，仪器将放置在温度控制的真空外壳中，并使用第二个稳定的激光监测梳线色散是否有任何必要的校正。目标是在现代稳定光谱仪的波长定标中达到优于10厘米/S的稳定度。

The detection of thousands of exoplanets over the past two decades has provided a Copernican-like shift in our view of the solar system. We now know that most stars in our galaxy form with planets. We also know that low mass planets are more common than the gas giant planets that were first detected in 1995. However, the measurement of planet masses for true Earth analogs (similar in mass and orbiting in the habitable zone) is not possible with current instruments. This proposal addresses a key requirement for improving precision by developing a precise, accurate, and stable wavelength calibration system for measurements of radial velocities with a new generation of ultra-stable spectrographs. This project will provide training opportunities for students and early-career scientists and help maintain US competitiveness in an area of science that captures the public imagination.The tunable Fabry-Pérot (FP) comb is designed for stability at the level of 1 cm/s, and the narrow lines can be used to calibrate out some of the instrumental uncertainties. The emission comb spectrum is produced by filtering a bright broadband laser-driven light source with the FP interferometer. The location of the comb peaks is determined by the spacing of the FP cavity. To prevent position drifts, the comb will be locked to a hyperfine laser transition with a precision that exceeds 1 part in ten billion. To prevent changes in the free spectral range or dispersion of the comb, the instrument will be placed in a temperature-controlled vacuum enclosure, and the comb line dispersion will be monitored for any required corrections with a second stabilized laser. The goal is to reach better than 10 cm/s stability in the wavelength calibration of modern stabilized spectrometers.