LaserCalc Pro

√τ scaling rule: LIDT_scaled = LIDT_spec × √(τ_your / τ_spec)
Valid for thermally-limited damage (ns → ps regime). In the fs regime (<10 ps) the ablation mechanism changes and scaling breaks down — use fs-specific LIDT data where possible.

Fluence on optic: F = E / (π × r²) for Gaussian beam at 1/e² radius.

B-integral: B = (2π/λ) × n₂ × I × L — accumulated nonlinear phase (radians).
B < 1 rad: safe. B > 1 rad: spectral/spatial distortion risk. B > 3 rad: likely filamentation/damage.

Critical power: P_cr = α·λ²/(n₀·n₂), α ≈ 3.77/(8π) for Gaussian beam.
Self-focusing occurs when P_peak > P_cr.

Pulse stretching (Gaussian): τ_out = τ_TL × √(1 + (4ln2·GDD/τ_TL²)²)
TBP: sech² → τ·Δν = 0.3148 | Gaussian → τ·Δν = 0.4413
GDD values shown are material GVD × thickness. Negative GDD = anomalous dispersion.