Fourier TBP: Gaussian Δτ·Δν = 2 ln 2/π ≈ 0.441 (transform-limited)

Fourier-transform duality pins a minimum time-bandwidth product (TBP) for any pulse with a specified temporal-intensity profile. For an intensity-FWHM Δτ Gaussian pulse, the spectral-FWHM Δν is bounded below by 2 ln 2/π ≈ 0.44127 —…