Pockel Cells
Conoptics offers a complete line of Electro-Optic modulators that employ the Pockels Effect (linear electro-optics effect). The Pockels Effect is a change in phase of the induced ordinary ray, relative to the extraordinary ray when an electric field is applied. This change in phase makes the crystals a voltage variable wave plate, such that the output polarization will change from linear to elliptical to linear as a function of the applied voltage.
Installing a polarizer at the pockel cells output (crossed or parallel to the input polarization) converts the polarization change to an intensity change called Amplitude Modulation