Brown Daniel, Cao Huy Tuong, Ciobanu Alexei, Veitch Peter, Ottaway David
Opt Express. 2021 May 24;29(11):15995-16006. doi: 10.1364/OE.425590.
Differential wavefront sensing is an essential technique for optimising the performance of many precision interferometric experiments. Perhaps the most extensive application of this is for alignment sensing using radio-frequency beats measured with quadrant photodiodes. Here we present a new technique that uses optical demodulation to measure such optical beats at high resolutions using commercial laboratory equipment. We experimentally demonstrate that the images captured can be digitally processed to generate wavefront error signals and use these in a closed loop control system for correct wavefront errors for alignment and mode-matching a beam into an optical cavity to 99.9%. This experiment paves the way for the correction of even higher order errors when paired with higher order wavefront actuators. Such a sensing scheme could find use in optimizing complex interferometers consisting of coupled cavities, such as those found in gravitational wave detectors, or simply just for sensing higher order wavefront errors in heterodyne interferometric table-top experiments.
差分波前传感是优化许多精密干涉测量实验性能的一项关键技术。这项技术应用最为广泛的或许是利用象限光电二极管测量射频拍频进行对准传感。在此，我们提出一种新技术，该技术利用光学解调，通过商用实验室设备以高分辨率测量此类光学拍频。我们通过实验证明，所捕获的图像可进行数字处理以生成波前误差信号，并将这些信号用于闭环控制系统，以将光束对准和模式匹配到光学腔中的波前误差校正至99.9%。该实验为与高阶波前致动器配合使用时校正更高阶误差铺平了道路。这样的传感方案可用于优化由耦合腔组成的复杂干涉仪，比如引力波探测器中的那些，或者仅仅用于外差干涉桌面实验中传感高阶波前误差。
