An apparatus for all-optical deflection of an incident optical signal beam, the apparatus comprising: a photorefractive semiconductor crystal; and an electric field source, for applying an electric field across the crystal either through electrodes or by positioning the crystal at a place where an electric field is present. In another embodiment of the invention a second optical beam source, for illuminating the crystal with a background optical beam. The apparatus is used for steering the signal beam, lensing it or for other applications.