Kavli Affiliate: David A. Muller
| First 5 Authors: Chia-Hao Lee, Steven E. Zeltmann, Dasol Yoon, Desheng Ma, David A. Muller
| Summary:
Electron ptychography has recently achieved unprecedented resolution,
offering valuable insights across diverse material systems, including in three
dimensions. However, high-quality ptychographic reconstruction is
computationally expensive and time consuming, requiring a significant amount of
manually tuning even for experts. Additionally, essential tools for
ptychographic analysis are often scattered across multiple software packages,
with some advanced features available only in costly commercial software like
MATLAB. To address these challenges, we introduce PtyRAD, an open-source
software framework offers a comprehensive, flexible, and computationally
efficient solution for electron ptychography. PtyRAD provides seamless
optimization of multiple parameters–such as sample thickness, local tilts,
probe positions, and mixed probe and object modes–using gradient-based methods
with automatic differentiation (AD). By utilizing PyTorch’s highly optimized
tensor operations, PtyRAD achieves up to a 17x speedup in reconstruction time
compared to existing packages without compromising image quality. In addition,
we propose a real-space depth regularization, which avoids wrap-around
artifacts and can be useful for twisted two-dimensional (2D) material datasets
and vertical heterostructures. Moreover, PtyRAD integrates a Bayesian
optimization workflow that streamlines hyperparameter selection. We hope the
open-source nature of PtyRAD will foster reproducibility and community-driven
development for future advances in ptychographic imaging.
| Search Query: ArXiv Query: search_query=au:”David A. Muller”&id_list=&start=0&max_results=3