Precision wavefront sensing and interferometry are essential in many fields of industry and fundamental research. Characterization of semiconductor devices, optics in lithography systems, and biologic features of living cells all require measurement resolution at the nanometer level. The field of high-contrast imaging in space-based astronomy has pushed wavefront sensing requirements to a new regime with current and future concepts requiring sensitivity on the order of 10 pm. Techniques to achieve this level of precision have been demonstrated, but require large, expensive instrumentation with custom light sources, and therefore do not provide a solution for in-space operation. Here we demonstrate experimentally the ability to detect picometer-level wavefront errors at spatial frequencies limited only by the pixel count of the sampling detector using a simple, inexpensive method. The system is based on the Zernike wavefront sensor (ZWFS) that implements the phase-contrast technique whereby the DC portion of an optical wavefront is phase-shifted with respect to its higher spatial frequency components. In our demonstration, a highly repeatable deformable mirror is used to introduce phase variations into an optical path. We readily sense 60 pm RMS changes in wavefront errors with the ZWFS system with measurement repeatability on the order of 0.6 pm. This technique is an enabling technology for future astronomy missions; however, there are widespread applications to many other fields requiring high-precision interferometry.

中文翻译：

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使用相衬技术检测皮克波前波前

精确的波前感测和干涉测量法在许多行业和基础研究领域都至关重要。半导体器件的表征，光刻系统中的光学器件以及活细胞的生物学特征都需要纳米级的测量分辨率。天基天文学中的高对比度成像领域将波前感测要求推向了一个新的领域，当前和未来的概念要求灵敏度在10 pm左右。已经证明了达到这种精度水平的技术，但是需要使用自定义光源的大型昂贵仪器，因此无法为太空操作提供解决方案。在这里，我们通过实验证明了使用简单，廉价的方法在仅受采样检测器像素数限制的空间频率上检测皮秒级波阵面误差的能力。该系统基于Zernike波前传感器（ZWFS），该传感器实现了相衬技术，从而使光波前的DC部分相对于其较高的空间频率分量发生了相移。在我们的演示中，使用高度可重复的可变形反射镜将相位变化引入光路。通过ZWFS系统，我们可以轻松地感知到60 pm RMS的波前误差变化，测量重复性约为0.6 pm。该技术是未来天文学任务的一项使能技术。然而，在需要高精度干涉测量的许多其他领域中，存在广泛的应用。