Photorefractive two-wave mixing phase coupling measurement in a self-stabilized recording regime

The measurement of the phase coupling between the two-wave mixed transmitted and diffracted beams behind a photorefractive material is directly obtained using a self-stabilized recording technique. These phase coupling data are used to compute the Debye screening length on an undoped Bi12TiO20 crystal. The diffraction efficiency, which is obtained in two different ways from the same self-stabilized experimental run, is similarly processed to compute the Debye length too. The Debye length is also measured for Pb- and Zr-doped Bi12TiO20 crystals, and from this parameter the corresponding effective density of traps is computed and shown to be lower than for the undoped sample.