Department of Electrical and Electronic Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen518055, China.
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen518055, China.
Ultramicroscopy. 2020 Jul;214:112990. doi: 10.1016/j.ultramic.2020.112990. Epub 2020 May 1.
Coherent modulation imaging (CMI) has been shown to be an effective lensless diffraction approach to imaging general extended samples with fast algorithmic convergence and high robustness to data imperfection. Being a single-shot technique, CMI holds a high potential for imaging dynamics with ultrafast pulses like the ones from free-electron lasers. In the reported work, strong modulators have been suggested for CMI to have the optimal performance, which may be an obstacle for the wide adoption of the method. Here we show that with our improved reconstruction algorithm the requirements on the modulation depth and feature size of a modulator can be relaxed. Furthermore, we demonstrate that when cascade configuration is used, the modulators can be even weaker while providing lower image errors in reconstruction than the case of a single modulator. Detailed numerical studies in both far-field and near-field experiment geometry are given via simulation. A relaxed requirement on modulators in CMI could pave the way for its wide use in biology and materials science.
相干调制成像（CMI）已被证明是一种有效的无透镜衍射方法，可用于对一般扩展样本进行成像，具有快速算法收敛和对数据不完善性的高度鲁棒性。作为一种单次拍摄技术，CMI 具有对超快脉冲（如自由电子激光）成像的巨大潜力。在报告的工作中，强烈建议使用调制器以获得最佳性能，这可能是该方法广泛采用的障碍。在这里，我们展示了通过我们改进的重建算法，可以放宽对调制器的调制深度和特征尺寸的要求。此外，我们还证明了当使用级联配置时，与单个调制器的情况相比，调制器可以更弱，同时在重建中提供更低的图像误差。通过模拟在远场和近场实验几何结构中进行了详细的数值研究。CMI 中对调制器要求的放宽为其在生物学和材料科学中的广泛应用铺平了道路。
