Broadband amorphous silicon OAM-generating Metasurface Simulation Framework

Broadband a-Si OAM Metasurface Simulation Framework v1.0.1 This patch release syncs this repository with Zenodo, creating a DOI indentifier. This is the release of our amorphous silicon OAM generating metasurface code for META-LIFI project, which was used in our article "VCSEL–Metasurface OAM Transmitters for High-Capacity Optical Wireless Links". It contains a comprehensive simulation framework for the design, fabrication, and analysis of amorphous silicon (a-Si) metasurfaces for Orbital Angular Momentum (OAM) beam generation. The release syncs this GitHub repository with Zenodo. This release provides a complete workflow, from unit cell characterization to lithography mask generation and far-field optical propagation, investigated across a broadband wavelength range (1214 nm – 1550 nm). Key Features 1. Unit Cell Characterization (siunitcell) Broadband RCWA: Automated scripts to sweep nanopillar radii and calculate phase/transmission response across the full telecommunication band. Material Support: Includes specific refractive index data for amorphous silicon (a-Si) on SiO2. Lookup Tables: Generates radiusData .mat files used as the foundation for metasurface design. 2. GDSII Mask Generation (gds_generation) Automated Layout: Scripts to map target OAM phase profiles to physical nanopillar geometries. Polystencil Integration: Uses Lumerical's polystencil command to generate precise vertex data for nanofabrication. Direct GDS Output: Exports standard .gds files ready for electron-beam lithography. 3. Beam Propagation & Analysis (oam_propagation) Near-to-Far Field Projection: Simulates the propagation of vector beams from the metasurface to the far field. Mode Decomposition: MATLAB tools to decompose output beams into Laguerre-Gaussian modes and quantify OAM purity. Efficiency Analysis: Automated calculation of transmission efficiency and propagation losses across the 1214–1550 nm range. Compatibility Simulation Engine: Ansys Lumerical FDTD/RCWA (Release 2020 or newer). Analysis: MATLAB (R2021b or newer). Documentation A detailed README provides step-by-step execution instructions. Specific Metadata files are included in every sub-directory to define variables, units, and experimental parameters.