High-performance phase camera as a frequency selective laser wavefront sensor for gravitational wave detectors.
High-performance phase camera as a frequency selective laser wavefront sensor for gravitational wave detectors.
复制标题
高性能相位相机作为引力波探测器的频率选择性激光波前传感器。
作者：
K. Agatsuma;L. van der Schaaf;M. van Beuzekom;D. Rabeling;J. van den Brand
我们设计、制造和测试了一台高性能的相位相机，它可以在很大的边带频率范围内观察激光波前。我们的相位相机扫描激光束通过针孔二极管，并使用外差技术来独立评估最多五个不同调制频率的上下边带中的信息。对于11个解调频率中的每一个，每秒并行地获得幅度和相位图像，每个图像由214个点组成。在光束中心处获得的灵敏度约为4×10-3 rad（λ/1600，λ = 1064 nm），对应于0.7 nm的波前变形，在光束尺寸上下降到约3 nm。这种灵敏度对于引力波探测器的诊断非常有用，并且符合Advanced Virgo控制回路的要求。我们报告我们的相位相机的设计，实现和性能。
We have designed, built and tested a high-performance phase camera, which can observe laser wavefronts in a large range of sideband frequencies. Our phase camera scans the laser beam over a pinhole diode and uses a heterodyne technique to independently assess the information in the upper and lower sidebands of up to five different modulation frequencies. Amplitude and phase images, consisting of 214 points each, are obtained every second for each of the 11 demodulated frequencies in parallel. The achieved sensitivity is about 4×10-3 rad (λ/1600 at λ = 1064 nm) at the center of the beam, corresponding to a wavefront deformation of 0.7 nm, and drops to about 3 nm over the beam size. This sensitivity is extremely useful for diagnostic purposes in gravitational wave detectors and fits the requirements for control loops in Advanced Virgo. We report on the design, realization and performance of our phase camera.