Sellmeier Calculator
Compute refractive index from Sellmeier coefficients for common optical materials. Includes Fresnel reflectance and Abbe number.
Input
Refractive Index — N-BK7
n
at 632.8 nm
n²
Fresnel Reflectance (Normal Incidence)
R per surface
((n−1)/(n+1))²
Two-surface T
(1−R)²
Dispersion (Visible)
nᵈ (587.56 nm)
n_F (486.13 nm)
n_C (656.27 nm)
n_F − n_C
principal dispersion
Abbe number Vᵈ
(nᵈ−1)/(n_F−n_C)
Abridged Optics — Sellmeier Calculator v1.0n²(λ) = 1 + Σ Bᵢλ²/(λ²−Cᵢ) · R = ((n−1)/(n+1))² · Vd = (nd−1)/(nF−nC)