Waveplate Retardation Calculator
Design waveplate thickness for a target retardation, or calculate retardation at any wavelength for a given thickness.
A waveplate introduces a controlled phase retardation between the ordinary and extraordinary polarization axes of a birefringent crystal. Retardation Γ = 2π(Δn·t)/λ depends on the birefringence Δn, plate thickness t, and wavelength λ. Half-wave plates (Γ = π) rotate linear polarization; quarter-wave plates (Γ = π/2) convert between linear and circular polarization. This calculator works in two modes: design mode (compute required thickness for a target retardation at a given wavelength) and analysis mode (compute retardation and polarization transformation for a given plate thickness across a wavelength range). Useful when selecting waveplates, designing polarization controllers, or checking retardation at an off-design wavelength.
Impractically thin for free-standing crystal — use thin-film or cemented design