This tool simulates the aberrated beam shape, i.e., distorted intensity profile, of the section of a focused Gaussian laser beam in a caustic plane within a certain range around the focal point of the focusing lens, given an aberrated phase map of a Spatial Light Modulator (SLM) near the light source. The simulation models the phase-intensity response of the high-power laser of the M290 PBF-LB/M system of EOS (Electro Optical Systems) GmbH. using analytical wave optics models. The models used for all optical components in the system are invertible; the simulation is implemented using PyTorch as a Neural Network class to make it differentiable; and the simulation supports simulating a batch of samples in parallel on GPUs. Such a simulation can be useful for system parameter fitting, optical aberration identification and quantification, computations requiring inverse simulation from the caustic plane back to the SLM plane, e.g., Gerchberg-Saxton algorithms.
The tool can be used by cloning the GitHub repository and installing the required dependencies.
The tool is responsible for modelling the intensity profile of the laser, the so-called beam shape, produced by a Computer-Generated Holography (CGH) phase mask loaded in a Spatial Light Modulator (SLM) with aberrations. The SLM can modulate the phase of the laser reflected on it by programming the voltage on each pixel of a crystal array to tilt the crystals in different angles causing desired phase delays on each pixel. However, the laser input to SLM can have power higher than 500W. The heat causes phase deviations, i.e., aberrations, on the SLM thus distorts the produced beam shape. The simulation models the focusing (lens), filtering (apertures), and the propagation of light from the SLM to caustic planes around the focal point. The beams shape is obtained by calculating the intensity of the propagated complex-value light field.
The tool operates in the following stages:
This tool is intended for:
Within the AIMS5.0 context, the tool is especially relevant for scenarios where precise beam shaping, aberration detection, and correction are needed in additive manufacturing industry. Distorted beam shapes caused by heat-generated aberrations in SLM can reduce the efficiency and quality of Laser-based Powder Bed Fusion of Metals (PBF-LB/M) process. This simulation lays the foundation of large dataset acquisition and algorithm development for beam shape correction to improve the efficiency and quality of PBF-LB/M.
If you use this tool in research or development, please cite the corresponding paper.
@article{yan2026efficient,
title={Efficient Gerchberg--Saxton algorithm deep unrolling for phase retrieval with a complex forward path},
author={Yan, Shengyuan and Holenderski, Mike and Meratnia, Nirvana},
journal={Advanced Photonics Nexus},
volume={5},
number={2},
pages={026005--026005},
year={2026},
publisher={Society of Photo-Optical Instrumentation Engineers (SPIE)}
}