Compute the focused beam waist and Rayleigh range of a Gaussian laser beam.
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Beam waist | w0 is the waist radius; intensity ∝ exp(−2r²/w²) | Kogelnik & Li 1966, Applied Optics |
| Far-field divergence | Half-angle θ = λ ÷ (π·w0); smaller waist diverges faster | Gaussian-beam propagation theory |
| Rayleigh range | zR = π·w0² ÷ λ, from waist to w=√2·w0 | Gaussian-beam parameter definition |
| Focused spot limit | Focused spot ≈1.22λ ÷ NA, the diffraction-limited size for marking/cutting | Laser-material-processing optics |