Srivastava Varun, Mansell Georgia, Makarem Camille, Noh Minkyun, Abbott Richard, Ballmer Stefan, Billingsley GariLynn, Brooks Aidan, Cao Huy Tuong, Fritschel Peter, Griffith Don, Jia Wenxuan, Kasprzack Marie, MacInnis Myron, Ng Sebastian, Sanchez Luis, Torrie Calum, Veitch Peter, Matichard Fabrice
Opt Express. 2022 Mar 28;30(7):10491-10501. doi: 10.1364/OE.445088.
The detectors of the laser interferometer gravitational-wave observatory (LIGO) are broadly limited by the quantum noise and rely on the injection of squeezed states of light to achieve their full sensitivity. Squeezing improvement is limited by mode mismatch between the elements of the squeezer and the interferometer. In the current LIGO detectors, there is no way to actively mitigate this mode mismatch. This paper presents a new deformable mirror for wavefront control that meets the active mode matching requirements of advanced LIGO. The active element is a piezo-electric transducer, which actuates on the radius of curvature of a 5 mm thick mirror via an axisymmetric flexure. The operating range of the deformable mirror is 120±8 mD in vacuum and an additional 200 mD adjustment range accessible out of vacuum. Combining the operating range and the adjustable static offset, it is possible to deform a flat mirror from -65 mD to -385 mD. The measured bandwidth of the actuator and driver electronics is 6.8 Hz. The scattering into higher-order modes is measured to be <0.2% over the nominal beam radius. These piezo-deformable mirrors meet the stringent noise and vacuum requirements of advanced LIGO and will be used for the next observing run (O4) to control the mode-matching between the squeezer and the interferometer.
激光干涉引力波天文台（LIGO）的探测器在很大程度上受量子噪声限制，需要注入压缩光态才能达到其全灵敏度。压缩光改善受压缩器与干涉仪元件之间的模式失配限制。在当前的LIGO探测器中，无法主动减轻这种模式失配。本文提出了一种用于波前控制的新型变形镜，可满足先进LIGO的主动模式匹配要求。有源元件是压电换能器，它通过轴对称挠曲作用于一块5毫米厚镜子的曲率半径。变形镜在真空中的工作范围是120±8 mD，在真空外还有额外200 mD的调节范围。结合工作范围和可调节的静态偏移，可将平面镜从-65 mD变形到-385 mD。测得的致动器和驱动电子设备的带宽为6.8 Hz。在标称光束半径上，测量到的高阶模式散射小于0.2%。这些压电变形镜满足先进LIGO严格的噪声和真空要求，并将用于下一次观测运行（O4），以控制压缩器与干涉仪之间的模式匹配。
