  We propose a new type of optical switch based on a ferroelectric. It is based
on the gap which exists for waves propagating from a dielectric to a
ferroelectric material. This gap depends on the polarization of the
ferroelectric. We show that it can be shifted by a control electromagnetic
pulse so that the material becomes transparent. This device would shift much
faster than the relaxation time of the ferroelectric (1 nano s). Estimates are
given for a real material.
