School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
Opt Lett. 2011 Jul 15;36(14):2746-8. doi: 10.1364/OL.36.002746.
All-reflective optical systems are under consideration for future gravitational wave detector topologies. A key feature of these all-reflective systems is the use of Fabry-Perot cavities with diffraction gratings as input couplers; however, theory predicts and experiment has shown that translation of the grating surface across the incident laser light will introduce additional phase into the system. This translation can be induced through simple side-to-side motion of the coupler, yaw motion of the coupler around a central point (i.e., rotation about a vertical axis), and even via internal resonances (i.e., vibration) of the optical element. In this Letter we demonstrate on a prototype-scale suspended cavity that conventional cavity length-sensing techniques used to detect longitudinal changes along the cavity axis will also be sensitive to translational, rotational, and vibrational motion of the diffractive input coupler. We also experimentally verify the amplitude response and frequency dependency of the noise coupling as given by theory.
全反射光学系统正在被考虑用于未来的引力波探测器拓扑结构。这些全反射系统的一个关键特点是使用带有衍射光栅的法布里-珀罗腔作为输入耦合器；然而，理论预测和实验已经表明，光栅表面在入射激光光上的平移会给系统引入额外的相位。这种平移可以通过耦合器的简单侧向运动、耦合器围绕中心点的偏航运动（即绕垂直轴旋转），甚至通过光学元件的内部共振（即振动）来诱导。在这封信中，我们在一个原型尺度的悬浮腔上进行了演示，传统的腔长感应技术用于检测沿腔轴的纵向变化，也将对衍射输入耦合器的平移、旋转和振动运动敏感。我们还通过实验验证了理论给出的噪声耦合的幅度响应和频率依赖性。
