Ronchi testing of a focused electromagnetic wave has in the last few years been used extensively at X‐ray free‐electron laser (FEL) facilities to qualitatively evaluate the wavefront of the beam. It is a quick and straightforward test, is easy to interpret on the fly, and can be used to align phase plates that correct the focus of aberrated beams. In general, a single Ronchigram is not sufficient to gain complete quantitative knowledge of the wavefront. However the compound refractive lenses that are commonly used at X‐ray FELs exhibit a strong circular symmetry in their aberration, and this can be exploited. Here, a simple algorithm that uses a single recorded Ronchigram to recover the full wavefront of a nano‐focused beam, assuming circular symmetry, is presented, and applied to experimental measurements at the Matter in Extreme Conditions instrument at the Linac Coherent Light Source.

中文翻译：

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圆对称波前的Ronchi剪切干涉法

过去几年，对聚焦电磁波的朗奇测试已广泛用于X射线自由电子激光（FEL）设施，以定性评估光束的波前。它是一种快速，直接的测试，易于即时解释，可用于对准相位板以校正畸变光束的聚焦。通常，单个Ronchigram不足以获取波阵面的完整定量知识。但是，通常在X射线FEL上使用的复合折射透镜在像差方面表现出很强的圆形对称性，因此可以加以利用。在这里，提出了一种简单的算法，该算法使用单个记录的Ronchigram，假设圆形对称，可以恢复纳米聚焦光束的整个波前，