A novel method for non-volatile holographic recording in lithium niobate

We present here a simple and practical solution to the erasure problem. The idea is to use two different deep traps, for example iron and manganese in lithium niobate. The energy band diagram for such a system is given. The electrons are initially in the deeper traps. Light of short wavelength (with high energy photons) can transfer some of these electrons to the shallower traps via the conduction band. This makes the recording of the holograms using longer wavelength light feasible. The final hologram is recorded in the deeper traps, and therefore is not erased during the read-out by the recording (long wavelength) light.