Materials reacting to electric pulses
One example would be a chamber containing pure nitrobenzene with electrodes on either side. Applying an electric field causes a rotation of the polarization of light passing through the chamber. Here's a reference to the original paper.

Since nitrobenzene is a dielectric, little current flows, and only a tiny amount of power is dissipated in the Kerr cell when the switching happens (due to losses in the dielectric). However the driving circuitry may well dissipate a fair bit of power if the switching occurs at a highly frequency.