Beam Width: FWHM ↔ 1/e² ↔ σ calculator
Convert between Gaussian beam width conventions.
Category: Unit Converters
Formula: σ = FWHM/(2√(2 ln2)) · 1/e² diam = 4σ ≈ 1.6986·FWHM
Inputs
| Input | Parameter | Unit | Default |
|---|---|---|---|
| FWHM | fwhm | µm | 100 |
Result with the default inputs
- FWHM: 100 µm
- σ: 42.4661 µm
- 1/e radius: 60.0561 µm
- 1/e² radius: 84.9322 µm
- 1/e² diameter: 169.8644 µm
Open it with your own values: put each input in the address as a parameter, for example /calculators/beam-width-fwhm-1-e2-sigma?fwhm=100. A unit other than the listed one goes in <parameter>_unit.
Read more: Wikipedia: Beam diameter