Pockelsceller
A Pockels cell is an electro-optic modulator that uses the Pockels effect, a linear electro-optic effect, to change the refractive index of a non-centrosymmetric crystal in response to an applied electric field. When an electric field is applied along a crystal axis, the ordinary and extraordinary indices shift differently, producing a controllable phase difference between polarization components. In a typical setup, the crystal is placed between polarizers so that the induced phase shift converts into intensity modulation; the voltage needed to produce a half-wave phase shift is called the half-wave voltage, Vπ.
The underlying relation is Δn ≈ −(1/2) n^3 r E, where n is the refractive index, r is
Materials commonly used for Pockels cells include lithium niobate (LiNbO3), potassium dihydrogen phosphate (KDP), potassium titanyl
Applications span laser pulse shaping and Q-switching, high-speed polarization control, and optical communication modulators. Practical design