Fresnel Reflection⚠ unverified
Physics / Optics · Compute the Fresnel reflection coefficient at normal incidence
Parameters
| Input | Symbol | Unit | Default | Description |
|---|---|---|---|---|
| n1 | n1 | — | 1.0 | Refractive index of the incident medium (dimensionless) |
| n2 | n2 | — | 1.0 | Refractive index of the transmitting medium (dimensionless) |
| theta | θ | — | 1.0 | Angle of incidence |
| Output | Symbol | Unit | Description |
|---|---|---|---|
| result | R | — | Reflectance (dimensionless), the fraction of intensity reflected |
The science & history
Understanding the Parameters
- $n_1$, $n_2$ — air→glass ≈ 4% per surface at normal incidence.
- $\theta$ — would matter for oblique Fresnel; currently ignored.
- $R$ — intensity reflection; transmittance $T \approx 1-R$ (no absorption).
Derivation (Approaching a Proof)
From boundary conditions on $E$ and $H$ at normal incidence, amplitude reflection $r = (n_1-n_2)/(n_1+n_2)$; power $R = |r|^{2}$ for real indices.
History
Augustin-Jean Fresnel; foundation of thin-film coatings and polarization optics.
Related Concepts: Brewster Angle, Snell's Law refraction angle, Critical Angle, Thin Film Thickness
Notes: Registry calculator fresnel-reflection (unverified). Unused input: $\theta$.
Normal incidence only.