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.

中文翻译：

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使用弱级联调制器高质量重建相干调制成像

相干调制成像 (CMI) 已被证明是一种有效的无透镜衍射方法，可对具有快速算法收敛性和对数据缺陷的高鲁棒性的一般扩展样本进行成像。作为一种单发技术，CMI 具有使用超快脉冲（如来自自由电子激光器的脉冲）进行成像动力学的巨大潜力。在报告的工作中，已建议使用强调制器使 CMI 具有最佳性能，这可能是该方法广泛采用的障碍。在这里，我们表明，使用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，我们证明，当使用级联配置时，调制器甚至可以更弱，同时在重建中提供比单个调制器更低的图像误差。通过模拟给出了远场和近场实验几何的详细数值研究。CMI 中对调制器的宽松要求可以为其在生物学和材料科学中的广泛应用铺平道路。