Beam Profiling

BeamFit is an in‑browser Gaussian beam profiling tool that fits the paraxial model $w(z)=w_0\sqrt{1+((z-z_0)/z_R)^2}$ independently to the horizontal and vertical axes ($w_x$, $w_y$) from measured beam widths versus axial position $z$. Paste measurements, pick units and width definition (1/e² radius/diameter, 1/e radius/diameter, or FWHM radius/diameter), and the app converts them to a consistent 1/e² radius, estimates $w_0$ and $z_0$ for each axis, and reports $z_R$, residuals, and a comparison table. An interactive chart overlays measured points with fitted curves, auto‑scales, and extends beyond the data to include the waist location. Complete sessions (inputs, SI‑converted data, and fit parameters) can be exported/imported as JSON .txt for Python analysis or round‑tripping back into the tool.

BeamFit - Gaussian Beam Profiling Toolkit
Measurement Data

Enter one sample per line. Columns are axial position and beam radii for horizontal (x) and vertical (y) axes. Headers are optional.

Fit Summary
Beam Profile Plot

Scatter points represent measured radii. Solid curves show the fitted Gaussian envelopes for each axis.

Tabulated Results
Fitted radii are evaluated at each measurement position for comparison.
z (m) z (in) wx meas (µm, 1/e²) wx fit (µm) wy meas (µm, 1/e²) wy fit (µm)
Export & Import

Export your dataset and fitted parameters as a .txt (JSON) file to analyze in Python, or load it back here to reproduce the fit.