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.