Pockels effect

The Pockels effect (named after Friedrich Pockels ), also known as the linear electro-optical effect , is the occurrence of birefringence or its change in special crystals to which an electrical voltage is applied. The change in birefringence takes place linearly with the change in the electrical field strength of the applied electrical field.

The effect describes the modulation of the refractive index of a material by an electric field according to the formula ${\displaystyle \Delta n}$ ${\displaystyle n}$

${\displaystyle \Delta n={n_{0}}^{3}\cdot r_{\mathrm {eff} }\cdot E}$

and occurs almost instantly. Here designated

• ${\displaystyle {n_{0}}}$ the unmodified refractive index of the material in the selected geometry
• ${\displaystyle r_{\mathrm {eff} }}$the effective electro-optical tensor , which depends on the crystal orientation and the polarization of the light
• ${\displaystyle E}$the field strength of the electric field .

The effect can u. a. in the Pockels cell are used to induce phase differences in birefringent crystals through targeted modification of the refractive index , which in turn can lead to polarization rotations.

In addition, the Pockels effect can also be used to describe the refractive index modulation in non-inversion symmetrical photorefractive crystals ; in inversion symmetrical crystals, however, only the Kerr effect occurs.

Web links

Commons : Pockels Effect  - collection of images, videos and audio files

• Leybold: Physics Leaflets - Pockels Effect (PDF; 139 kB)