Fresnel Reflectance Calculator
Calculate s-pol, p-pol, and average Fresnel reflectance at a dielectric interface. Computes Brewster's angle, critical angle, and multi-surface system transmittance.
When light crosses the boundary between two optical media, a fraction reflects and the rest transmits. The Fresnel equations determine these fractions separately for s-polarized (TE) and p-polarized (TM) light as a function of incidence angle and the refractive indices on each side. This calculator computes s-pol and p-pol reflectance across all angles, identifies Brewster's angle (where p-pol reflection vanishes) and the critical angle for total internal reflection, and estimates multi-surface transmittance for a stack of N identical interfaces. Use this tool when designing anti-reflection coatings, evaluating window insertion losses, or working with Brewster windows in laser cavities.