Beam Diffraction Utility

Simulate free-space Gaussian beam propagation using the Angular Spectrum Method (ASM) — a physically exact Fourier-domain technique valid from the near field to the far field. Choose 2D for full beam profiles or 1D for fast X-axis cross-sections. Optionally apply a thin lens or Δn phase object. All computation runs directly in your browser.

Beam & Propagation Parameters

Simulation Mode

Wavelength (nm)

800

Beam FWHM — X (µm) (intensity)

2000

Beam FWHM — Y (µm) (intensity; blank = same as X)

2000

Propagation Distance (mm)

400

Thin Lens Δn Phase Object

Focal Length (mm)

Object Size X (µm)

Object Size Y (µm)

Δn (index change)

Object Thickness (µm)

⚙ Advanced Settings

Refractive Index n₀

Min. Grid Size (pixels)

Propagation Steps

Computed Parameters

Rayleigh range z_R —

z / z_R —

Est. output FWHM —

Grid window —

Pixel size —

Actual grid —

Phase shift Δφ —

Physics check —

Optical Setup — 3D Preview drag to rotate • updates live • transverse scale in µm, z in mm

1 Set parameters & run simulation

2 Press Play to watch beam evolve

Ready — set your parameters above, then press Run Simulation.

Beam Profile at z = 0 mm

z = 0 mm

Peak Intensity vs Propagation Distance

Beam FWHM vs Propagation Distance

Beam Diffraction Propagation

Beam & Propagation Parameters

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