Optimization of non-volatile two-color holographic recording in near-stoichiometric LiNbO₃

We investigate two-color holography using Tb doped near-stoichiometric LiNbO 3 . We present the measurements of the hologram strength and sensitivity dependences on the wavelength and intensity of the writing near-IR laser light and on the gating UV light intensity. The diffraction efficiency of the holograms is satisfactory when the writing light wavelength is below 800 nm. The rapidly changing sensitivity around the photon energy of 1.6 eV is an indication that small polarons are involved in the recording mechanism. The recording speed mainly depends on the gating beam intensity, while the hologram strength is much more affected by the writing beam properties, both the intensity and wavelength. We show how to choose appropriate intensities to optimize the desired two-color performance that can be also applied to other two-color schemes.