Position-guided ptychography for vibration suppression with the aid of a laser interferometer

Abstract

As a variant of the coherent X-ray diffraction imaging (CDI) method, ptychography provides an ultrahigh resolution of sub-10 nm for extended samples through iterative phasing of diffraction patterns; this advantage makes ptychography have great application potential in nanoscience, materials, biology and magnetics. However, irregular vibrations of motion stages in ptychography experiment system can induce incoherent blurring of diffraction patterns, thereby resulting in degradation of recovered image quality. Herein, we propose a new ptychography approach, termed position-guided vibration separation, to improve ptychography reconstruction in the presence of sample random vibration relative to the illumination by utilizing the instantaneous position data recorded by a laser interferometer (LIM) during exposures of the pixel detector. This approach provides a solution to the sample-stage random vibration problem by mapping the object mixed states onto the LIM-measured vibrational positions. Both the simulation and experimental results demonstrate the effectiveness of this approach in suppressing the random vibration effects on ptychography. Therefore, this new approach can significantly decrease the mechanical stability requirements on ptychography experiment instruments.