论文标题
重力微弱：使用快速计量衰减系统减少重力$^+$的噪声源
GRAVITY faint: reducing noise sources in GRAVITY$^+$ with a fast metrology attenuation system
论文作者
论文摘要
随着从重力到重力$^+$的升级，仪器将演变成一个全天空干涉仪，可以观察到微弱的目标，例如高红移AGN。观察最微弱的目标需要尽可能减少重力的噪声源。主要的噪声源，尤其是在光谱的蓝色部分，是计量激光光的反向散射到检测器上。为了减少这种噪音，我们引入了两种新的计量模式。通过小型硬件更改和软件适应的结合，我们可以在观察过程中调节计量激光器，而不会失去阶段参考。对于单光束目标，我们甚至可以关闭测量器上最大SNR的计量激光器。这些变化导致SNR在整个频谱中平均超过两倍，并且在目前以激光噪声为主的频谱中达到了八倍。
With the upgrade from GRAVITY to GRAVITY$^+$ the instrument will evolve into an all-sky interferometer that can observe faint targets, such as high redshift AGN. Observing the faintest targets requires reducing the noise sources in GRAVITY as much as possible. The dominant noise source, especially in the blue part of the spectrum, is the backscattering of the metrology laser light onto the detector. To reduce this noise we introduce two new metrology modes. With a combination of small hardware changes and software adaptations, we can dim the metrology laser during the observation without losing the phase referencing. For single beam targets, we can even turn off the metrology laser for the maximum SNR on the detector. These changes lead to an SNR improvement of over a factor of two averaged over the whole spectrum and up to a factor of eight in the part of the spectrum currently dominated by laser noise.
