Simulation package for solving dynamic diffraction problems in deformed crystals. Bragg, Laue geometry, asymmetric reflections, bend crystals, dislocations, crystals with arbitrary shapes, strain distributions and time dependent problems

TL;DR

This paper presents a Python-based FFT Beam Propagation Method for efficiently simulating dynamic diffraction in deformed crystals with arbitrary shapes, including bent crystals, dislocations, and strain effects, validated against literature results.

Contribution

Introducing a fast, easy-to-implement FFT BPM approach for dynamic diffraction simulation in complex crystal geometries and strain conditions, with open-source Python code.

Findings

Successfully reproduces literature results for bent crystals and dislocations.

Provides a computationally efficient and parallelizable Python implementation.

Applicable to a wide range of crystal deformation and shape scenarios.

Abstract

We demonstrate the use of the Fast Fourier Transform Beam Propagation Method (FFT BPM) to simulate dynamic diffraction effects, including scattering from deformed crystals with arbitrary shapes in Bragg, Laue, and asymmetric geometries. The method's straightforward algorithm, combined with FFT, enables fast computation and is easy to implement in Python. It successfully reproduces literature results for bent crystals, dislocations, and finite-shaped crystals simulated using the Takagi-Taupin equations. Python implementations for each case are provided in a public GitHub repository, with the code structured for parallel computing.